U.S. patent application number 09/080241 was filed with the patent office on 2002-02-28 for retargetable information processing system.
Invention is credited to DOMEN, SINGI, KOHNO, TOSHIAKI, KOIZUMI, SHINOBU, KYUSHIMA, ICHIRO, WATANABE, TAN.
Application Number | 20020026633 09/080241 |
Document ID | / |
Family ID | 14041646 |
Filed Date | 2002-02-28 |
United States Patent
Application |
20020026633 |
Kind Code |
A1 |
KOIZUMI, SHINOBU ; et
al. |
February 28, 2002 |
RETARGETABLE INFORMATION PROCESSING SYSTEM
Abstract
A translator system for translating source programs into machine
language programs in an electronic computer system. An object
program common to a plurality of different machine types of
computers are generated while implementing execution performance
equivalent to object programs inherent to the computers. A compiler
translates a source program into an abstract object program
including an abstract machine instruction sequence and indication
concerning allocation of abstract registers. An installer converts
the abstract object program into a machine language program of
target computer on the basis of executable computer specification
information including register usage indication and machine
instruction selecting rules.
Inventors: |
KOIZUMI, SHINOBU;
(SAGAMIHARA-SHI, JP) ; KYUSHIMA, ICHIRO;
(YOKOHAMA-SHI, JP) ; WATANABE, TAN; (YOKOHAMA-SHI,
JP) ; KOHNO, TOSHIAKI; (MACHIDA-SHI, JP) ;
DOMEN, SINGI; (FUJISAWA-SHI, JP) |
Correspondence
Address: |
ANTONELLI TERRY STOUT AND KRAUS
SUITE 1800
1300 NORTH SEVENTEENTH STREET
ARLINGTON
VA
22209
|
Family ID: |
14041646 |
Appl. No.: |
09/080241 |
Filed: |
May 18, 1998 |
Current U.S.
Class: |
717/146 ;
714/E11.209; 714/E11.21 |
Current CPC
Class: |
G06F 11/3624 20130101;
G06F 8/47 20130101; G06F 8/447 20130101; G06F 11/362 20130101; G06F
11/3664 20130101 |
Class at
Publication: |
717/146 |
International
Class: |
G06F 009/45 |
Foreign Application Data
Date |
Code |
Application Number |
Apr 23, 1998 |
JP |
03-091980 |
Claims
1. An information processing system, comprising: a compiler for
translating source programs into abstract object programs; a linker
for linking together said abstract object programs to generate a
linked abstract object program; and a plurality of installers
provided for different types of machines, for translating said
linked abstract object program into machine language programs
respectively.
2. An information processing system according to claim 1, wherein
said abstract object program is composed of a sequence of
instructions for an abstract register machine, wherein said
abstract register machine including a plurality of registers and
executing transfer instructions between said registers and a
memory, computational instructions on the registers and branch
instructions for controlling a sequence of executions of said
instructions, and wherein said installers being provided in a
number corresponding to a number of different instruction set
computers in which instruction specifications differ from one
another, wherein one and the same abstract object program resulting
from the translation of said source program by said compiler is
translated into said machine language programs oriented to said
different machine types of the computers, respectively, by means of
said installers provided in association with said computers,
respectively, for thereby allowing machine language program to be
executed by the target computer to which said machine language is
oriented.
3. An information processing system according to claim 2, wherein
said abstract object program includes, in addition to machine
language corresponding instructions representing machine
instructions for the target computers, at least one of instructions
selected from a group consisting of a generation control
instruction for controlling generation of a machine instruction
sequence a pseudo-instruction representing a structure of a
program, a pseudo-instruction for establishing correspondences
between instructions in the program and symbol names, a
pseudo-instruction for establishing correspondences between
locations or sizes of the memory used by the program and symbol
names and a pseudo-instruction indicating debugging
information.
4. An information processing system according to claim 3, wherein
said abstract object program includes indication for selecting the
positions for generation of machine instruction sequence of the
computer indicated by said machine instruction sequence
corresponding instruction in conformance with register allocation
state in which said registers are allocated.
5. An information processing system according to claim 2, wherein
said abstract object program includes at least one of an indication
for allocation of said registers and an indication for freeing said
registers.
6. An information processing system according to claim 2, wherein
said abstract object program includes at least one of an
indications concerning types of said registers, priorities of the
registers in the allocation of said registers and a number of the
registers to be preserved.
7. An information processing system according to claim 6, wherein
said register allocation priority is determined in dependence on
the use frequency of the abstract register or use position
thereof.
8. An information processing system according to claim 2, wherein
said compiler has a function for performing conversion of the
instruction sequence, deletion of instruction, modification of
instruction or move of instruction for thereby evading duplicative
execution of the instruction in said abstract register machine
instruction sequence.
9. An information processing system according to claim 2, wherein
said installer has a function for allocating physical registers of
said computer to the registers in said abstract object program in
conformance with indication of a memory designation
pseudo-instruction included in said abstract object program upon
generation of said machine language program of said computer from
said abstract object program.
10. An information processing system according to claim 2, wherein
said installer has a function for selectively determining whether
allocation of physical registers of said computer to the registers
of said abstract register machine is to be executed offhand or not
or for messaging whether said physical registers could be allocated
or not.
11. An information processing system according to claim 2, wherein
said installer has a function for recording priorities of physical
registers of said computer in allocating said physical registers to
the registers of said abstract register machine even after
allocation command has been issued.
12. An information processing system according to claim 2, wherein
said installer has a function capable of changing priorities of
physical registers of said computer upon allocating said physical
register to abstract registers constituting said registers of the
abstract register machine, even after said allocation priorities
have been specified, in conformance with position of said abstract
register machine instruction being executed or position of said
abstract register instruction using said abstract register.
13. An information processing system according to claim 2, wherein
said installer has a function of generating the machine language
program in a form in which a machine language instruction sequence
is changed in conformance with structures of preceding and
succeeding instruction sequences, regardless of a form of the
abstract register machine instruction sequence which corresponds to
said machine language instruction sequence.
14. An information processing system according to claim 13, wherein
said installer has a function of generating the machine language
program in a form in which a machine language instruction sequence
is changed in conformance with situation in which physical
registers of the computer are allocated regardless of a form of the
abstract register machine instruction corresponding to said machine
language instruction sequence.
15. An information processing system according to claim 13, wherein
said installer has a function for optimalizing the machine language
program in conformance to characteristics of the computer.
16. An information processing system according to claim 2, wherein
said installer generates the machine language program from the
abstract object program in accordance with machine language
instruction generating rules established for said abstract register
machine instruction sequence.
17. An information processing system according to claim 15, wherein
said installer has a function capable of generating from one and
the same abstract object program different machine language
programs conforming to the target computers by changing the machine
language instruction generating rules for said abstract register
machine instruction sequence in conformance to the target
computers.
18. An information processing system, comprising; a compiler for
translating a source program into object programs; and a target
computer for executing computational operations in accordance with
instructions of said object programs; wherein each of said object
programs includes in addition to executable instructions sequence
for said target computer at least one of instructions selected from
a group consisting of a generation control instruction for
controlling allocation or release of registers, a
pseudo-instruction representing a structure of the source program,
pseudo-instructions for establishing positions of instructions in
the program and symbol names, pseudo-instructions for establishing
correspondences between locations or sizes of memory used by the
program and symbol names and pseudo-instructions and a
pseudo-instruction for indicating debugging information.
19. A machine language program generating system, comprising: a
compiler for translating source programs into abstract object
programs each including an abstract register machine instruction
sequence; a linker for linking together a plurality of said
abstract object programs to thereby generated a linked abstract
object program; and an installer for translating a given one of
said abstract object programs into a machine language program which
is stored in a memory of a computer; wherein said installer is
provided for each of the computers having instruction schemes
differing from one another, to thereby allow a processing operation
indicated by one and the same abstract object program to be
executed by each of said plural computers in different instruction
set.
20. A debug system loaded with a source program described in a
high-level language and an abstract object program generated by
translating said source program, wherein said abstract object
program has a plurality of abstract registers and is composed of an
abstract register machine instruction sequence which includes a
transfer instruction between said register and a memory, a
computational instruction executed on said registers and a control
instruction for controlling the sequence of instructions, said
debug system further comprising means for translating said abstract
object program into an executable machine language program.
21. A debug system according to claim 19, wherein one and the same
abstract object program is executed by a plurality of different
machine types of computers.
22. A debug system according to claim 19, wherein one and the same
debug system is implemented by a plurality of different machine
types of computers.
23. An information processing system, comprising: a portable
storage medium; and an information processor for performing data
transactions with said portable storage medium loaded in said
information processor; wherein said portable storing medium stores
therein an abstract object program which includes a plurality of
abstract registers and is composed of an abstract register machine
instruction sequence including a transfer instruction between said
register and a memory, computational instructions for said
registers and an instruction for controlling the sequence of said
computational instructions, said information processing system
further including means for reading and translating said abstract
object program into an executable machine language program.
24. An information processing system according to claim 22, wherein
said portable storage medium is constituted by an IC card.
25. An information processing system according to claim 22, wherein
said portable storage medium is constituted by a CD-ROM.
26. A network computer system in which a plurality of different
instruction set of computers are connected to a network; wherein at
least one of said computers connected to said network functions as
a server equipped with the abstract object program set forth in
claim 2; each of the other computers connected to said network
including means for accessing said abstract object program of said
server and the installer set forth in claim 2; and each of said
other computers connected to said network translating said abstract
object program supplied from said server into respective machine
language programs for execution thereof by means of said installer
provided in association with each of said other computers.
27. A computer system replacing method, comprising steps of:
replacing a computer system incorporating the abstract object
program and the installer set forth in claim 2 by another computer
system equipped with the installer set forth in claim 2; and
executing the abstract object program before said replacement by
the computer system after said replacement.
28. A method of generating from at least one source program a
machine language program suitable for a type of computer, the
method being executed by a computer system and comprising the steps
of: compiling said at least one source program to generate an
abstract object program for an abstract machine; and translating
said abstract object program into a machine language program in
accordance with a type of computer, the machine language program
being executed by the computer.
Description
BACKGROUND OF THE INVENTION
[0001] The present invention relates to a translation system for
translating a source program into a machine language program by
using an electronic computer and more particularly to a translation
system of the type mentioned above in which an object program
common to a plurality of target computers or machines of different
types can profitably be employed.
[0002] Systems for allowing programs described in high-level
languages to be executed on the target computers or machines are
generally classified into two systems respectively referred to as a
compiler system and an interpreter system.
[0003] In the compiler system, a program described in a high-level
language is translated into a machine language program oriented to
a target computer, and the machine language program is executed
straightforwardly by the target machine.
[0004] On the hand, in the case of the interpreter system, a
language (referred to as the intermediate language) which differs
from the machine language of the target computer is prepared along
with a program (referred to as the interpreter) which is adapted to
interpret and execute the intermediate language program on the
target computer. In other words, the high-level language program is
once translated into the intermediate language program which is
then executed by the target computer or machine on which the
interpreter program runs.
[0005] One of advantages of the compiler system over the
interpreter system is seen in a high-speediness of program
execution which can be explained by the facts mentioned below.
[0006] (1) In the interpreter system, there are required in
addition to the execution of a machine language program
corresponding to an intermediate language program, allocation of
the processings for the intermediate language codes as well as
address calculation for operands and others. On the other hand, in
the compiler system, such processing allocation and address
calculation are rendered unnecessary because the machine language
program can directly be executed in a straightforward manner.
[0007] (2) In the compiler system, sparing or deletion of some of
the processings is possible by taking into consideration the
context of program and characteristics of the target computer (i.e.
program optimalization can be realized). In contrast, the
interpreter can only execute the intermediate language program as
it is because of its universalness to the intermediate languages
and thus the interpreter is not in the position to allow any
processing to be spared or omitted in consideration of the program
context. Besides, since the characteristics of the target computer
or machine are not reflected onto the intermediate language
program, it is impossible to speed up the processing by resorting
to, for example, mapping of specific variables described in a
high-level language to the registers incorporated in the target
machine.
[0008] On the other hand, as to the usage of a program destined to
be executed repetitively, there has heretofore been adopted either
one of the two methods mentioned below.
[0009] (1) According to a first method, the compiler system is
adopted, wherein the machine language program obtained through the
translation is preserved or stored so as to be repetitively
executed in a straightforward manner.
[0010] (2) According to the other method, the interpreter system is
adopted, wherein the intermediate language program is stored for
allowing repetitive executions thereof by the interpreter.
[0011] When one program is to be executed repetitionally, the
compiler system is adopted by an overwhelming majority from the
viewpoint of reduction of the time involved in execution of the
program. However, the compiler system suffers from the
undermentioned shortcomings.
[0012] (1) It is necessary to provide the compiler for translating
a source program into a machine language program for each type of
the target machine, which means that not only a quantity of
compilers to be developed will necessarily increase but also
overhead involved in maintenance and extension is significantly
increased because the maintenance and extension must be performed
so as to be compatible with the machine types of the target
computers.
[0013] (2) In the case where one and the same program is to be
executed by a plurality of target computers of different machine
types, compilation (i.e. translation from a source program to a
machine language program) is required for each of the machine types
of the target computers, which results in that overhead in the
management of the machine language programs increases
remarkably.
[0014] (3) In an environment in which a plurality of computers of
different machine types are connected to a network, a number of
machine language programs which correspond to the number of the
computers connected to the network are required for one and the
same source program, which gives rise to problems with regards to
the version management and disk space availability. Moreover,
difficulty will be encountered in distributed execution of one and
the same program.
[0015] (4) Some of the systems used actually is often operated with
only the machine language program without any source program given.
In such system, exchange or switching and alterations of the
component machines is difficult to realize. At present, progress in
the hardware technology facilitates implementation of highly
sophisticated computer architecture. Nevertheless, inheritance of
the machine language program resources imposes a serious limitation
to alteration or modification of the computer architecture.
[0016] For overcoming the disadvantages of the compiler system
mentioned above, such a system may be conceived in which an
intermediate language program which is independent of any specific
machine is employed for the purpose of preservation or storage and
management of the program, wherein upon execution, the intermediate
language program is translated into a machine language program of a
target machine for thereby realizing a high-speed processing, i.e.
a system which adopts only the advantageous features of the
compiler system and the interpreter system in combination. In the
present state of the art, however, there is known no real system
which incarnates the concept mentioned above.
[0017] Parenthetically, for details of the compiler system and the
interpreter system, reference may be made to "A. Aho, R. Seti and
J. Ullman: Compilers. Principles, Techniques and Tools",
Addison-Wesly, 1986, pp. 1-24.
[0018] In order to allow a machine-independent intermediate
language program (i.e. intermediate language program which is
independent of any specific target machine or computer) to be
adopted as a form for preservation and management of a program to
be executed repeatedly, it is required that the intermediate
language program can be executed at a speed comparable to that of
execution of the machine language program in the existing compiler
system.
[0019] To this end, fulfillment of the requirements mentioned below
will be indispensable.
[0020] (1) The intermediate language program which is in the form
suited for the preservation and management as described above is
not executed by the interpreter but translated into a machine
language program immediately before the execution.
[0021] (2) In the course of the translation or conversion of the
intermediate language program into the machine language program,
optimalization of the program is carried out by taking into
consideration the characteristics of the target computer which is
to execute that program.
[0022] With the present invention, it is contemplated to provide a
consolidated or integrated system which can realize the
requirements mentioned above, i.e. to provide a practical form of
an intermediate language for storage and management of the
intermediate language program together with a practical method of
effectuating the translation of the intermediate language program
into the machine language program upon start of execution of the
program while optimalizing the machine language program for the
target computer.
[0023] In this conjunction, it is noted that the intermediate
language code designed for the interpreter system can not be used
as the intermediate language codes for realizing what is
contemplated with the present invention for the reasons described
below.
[0024] (1) The intermediate language code for the interpreter
system contains no information required for optimalization to be
effectuated upon translation into the machine language program
because the intermediate language codes are not designed on the
premise that it undergoes the optimalization by the
interpreter.
[0025] (2) The computers may globally be classified into a register
machine which includes a finite number of registers and in which
operations are performed primarily on the registers and a stack
machine which includes operation stacks, wherein the operations or
computation is performed primarily on the stack. In the current
state of the art, a majority of the existing computers are
implemented as the register machines. By contrast, many of the
intermediate languages for the interpreter systems are designed on
the presumption of operation on the stack because of the ease in
designing the intermediate language codes and the interpreter. Of
course, it is not absolutely impossible to convert the on-stack
operation to the operation on the registers. However, a great
difficulty will be encountered in translating the intermediate
language program for the stack machine into an efficient and
effective machine language program for the register machine, when
considering the fact that the values on the stack are inherently
assumed to be disposable, while those on the registers should
rationally be used repetitively as far as it is possible in order
to make the most of the registers with a high efficiency.
SUMMARY OF THE INVENTION
[0026] It is therefore an object of the present invention to
provide information processing method and system in which an
intermediate language program independent of any specific computer
or machine is used for storage, management and the like purpose and
translated into a machine language program appropriate to a target
machine immediately before execution of the program by the target
machine. More specifically, it is contemplated with the present
invention to provide an information processing system which can
fulfill the requirements described below.
[0027] (1) Putting preponderance on a register machine as the
target machine (i.e. execution-destined computer), the intermediate
language program be of such an instruction sequence in which
existence of registers is presumed at the very level of
intermediate language program. Besides, in the course of
translation up to the intermediate language program, optimalization
should have been effectuated to a possible extent.
[0028] (2) Upon translation into the machine language program from
the intermediate language program, a register utilization method
should be able to be optimalized. More specifically, utilization of
the registers should be so determined that the number of times the
instructions for loading and storing values to and from registers
should be reduced to a minimum while allowing unnecessary
instructions to be deleted. Moreover, information requisite for the
optimalization should be derived from the intermediate language
program.
[0029] (3) In some case, a specific sequence (a series of plural
instructions) in the intermediate language program can be replaced
by an instruction peculiar to the target machine. In such case, it
is preferred in general from the standpoint of efficiency to
effectuate the replacement by one machine language instruction.
Accordingly, when a machine language instruction corresponding to a
succession of intermediate language instructions exists availably
by the target machine, a machine language program should be
generated such that the corresponding machine language instruction
mentioned above can be made use of.
[0030] Aspects of the present invention in general may be
summarized as follows.
[0031] 1. System Structure
[0032] According to an aspect of the present invention, a system
for translating a source program into a machine language program
for an execution-destined computer or target machine is composed of
three subsystems. They are:
[0033] (1) a compiler: a subsystem for generating an object program
(referred to as abstract object program) which is independent of
the type of the target machine,
[0034] (2) a linker: a subsystem for linking together a plurality
of abstract object programs generated by the subsystem compiler
into a single abstract object program, and
[0035] (3) an installer: a subsystem for translating the abstract
object program outputted from the linker into a machine language
program for the target machine (which may also be referred to as
the target computer, execution-destined machine or the like).
[0036] 2. Form of Object Program
[0037] In order to make the object program common to a plurality of
target machines, an abstract register machine (also referred to as
ARM or Arm in abbreviation) having a plurality of registers is
presumed, wherein an instruction sequence for the abstract register
machine or ARM is made use of as a basic part of the common object
program (referred to as the abstract object program).
[0038] The abstract register machine or ARM has features mentioned
below.
[0039] (1) The ARM has a plurality of abstract registers. (Although
the number of the abstract registers is infinite in principle,
limitation is imposed in dependence on the form of the abstract
object program in practical applications.)
[0040] (2) The ARM has as the instruction executing functions a
register-memory data transfer function, function for performing
operations on the registers (such as four arithmetic operations,
logical operations, shift operations, comparisons) and an execution
control function (such as unconditional branch, conditional branch,
call and restoration of subprograms, etc.).
[0041] (3) Memory addresses are represented by symbol names rather
than numerical values.
[0042] The reason why the instruction sequence of the abstract
register machine or ARM including a plurality of registers is made
use of as the basic part of the common object can be explained as
follows:
[0043] (a) In order to speed up the translation of the object
program into machine language programs appropriate to the
individual target machines, respectively, it is desirable to reduce
as for as possible semantic gaps between the object program and the
machine language. In this conjunction, it is to be noted that the
computation machine used widely at present is a register machine
having a plurality of registers. Accordingly, by presuming the
abstract register machine having as an instruction set a
semantically common part of the instruction sets of the
conventional register machines, overhead involved in the
semantically meaningful translation can be reduced, whereby the
translation to the machine language program can be speeded up.
[0044] (b) In the register machine, one of the keys for speeding up
execution of the machine language program is effective utilization
of the registers. Thus, by regarding the abstract register machine
or ARM as a target machine for the compiler, the latter can
generate a instruction sequence which can make use of the registers
to a maximum possible extent.
[0045] The abstract object program is composed of:
[0046] (a) instruction sequence forth ARM,
[0047] (b) pseudo-codes such as definitions of labels concerning
branch, entry, variable and constant, embedded information for the
optimalization, and embedded information for the debugging at the
source program level,
[0048] (c) generation control specifiers (indicating
allocation/deallocation of abstract registers and selection of an
ARM instruction sequence in the state in which the abstract
registers have been allocated), and
[0049] (d) dictionaries of variable names and index names for
reference in the debugging at the level of the source program.
[0050] Although the type of the abstract register can be indicated
by the generation control specifier for the abstract registers, it
is impossible to designate to which of the registers in the real
machine the indicated abstract register correspond. In this manner,
the registers can be surfaced up in the abstract object program
independent of the type of the target machine.
[0051] 3. Specification of Target Machine
[0052] In order to allow the machine language programs for the
target machine to be generated from the abstract object program,
tow types of information mentioned below are prepared for the
installer:
[0053] (i) indication concerning the usage of the register in the
target machine (types and number of the usable registers), and
[0054] (ii) translation rules for translation of the instruction
sequence pattern of the ARM into an instruction sequence pattern
for the target machine.
[0055] At this juncture, it should be mentioned that the ARM
instruction pattern and that of the target machines are each
composed of a plurality of instructions.
[0056] The instructions of the ARM and those of the target machine
are not set in one-to-one correspondence relation, the reason for
which is explained as follows.
[0057] (1) In a strict sense, the ARM instruction set can not
constitute a common part of real machine instruction sets.
Accordingly, there may arise such situation in which the
instruction corresponding to that of the ARM is absent in the
instructions executed by the a target machine. In that case, it is
necessary to realize one ARM instruction by several instructions of
the target machine.
[0058] (2) There may arise a situation which is reverse to that
mentioned above. In other wards, the instruction sequence executed
by the target machine may include an instruction which corresponds
to a sequence of several ARM instructions, as exemplified by a
register-memory operation instruction and the like. In this case,
the ARM instruction sequence is handled as one target machine
instruction, because the processing speed can be enhanced by
decreasing the number of the instructions to be executed by the
target machine.
[0059] 4. Method of translating the abstract object program into a
machine language program for a target machine.
[0060] The installer includes a table for managing correspondences
between the abstract registers of the ARM and the real registers of
the target machine (this table will hereinafter be referred to as
the register management table) and performs operations mentioned
below.
[0061] (1) In response to an abstract register allocation command
for the abstract registers in the abstract object program, the
installer attempts to establish correspondence between an abstract
register and a real register. In that case, when there exists a
real register for which correspondence with other abstract register
has not been established within a range described in register usage
indication of the target machine specifications, i.e. where there
is found an idle real register, correspondence is established
between the aforementioned abstract register and the idle real
register.
[0062] (2) In response to a register releasing or freeing command
contained in the abstract object program, the installer clears the
correspondence relation between the abstract register and the real
register (i.e. deallocation is executed by the installer).
[0063] (3) With the aid of the generation control specifier
contained in the abstract object program, the installer checks
whether or not an abstract register is set in correspondence
relation with a real register, whereon an ARM instruction sequence
is selected.
[0064] (4) For the ARM instruction sequence thus selected, the
installer applies translation rules contained in the target machine
specifications for translating the ARM instruction sequence pattern
into a target machine instruction sequence pattern, to thereby
generate a target machine instruction sequence corresponding to the
selected ARM instruction sequence while replacing the abstract
register identification number by that of the real register.
[0065] (5) For the target machine instruction sequence thus
generated, the installer converts the symbol name representing the
memory address into numeric addresses.
[0066] The compiler which may be implemented by applying compiler
techniques known heretofore serves for translation of a source
program into an abstract object program. Simultaneously, the
compiler performs optimalization at the source program level as
well as optimalization of the ARM instructions for which
utilization of the registers is prerequisite.
[0067] In this way, the installer generates a machine language
program for a target machine from an abstract object program in
conformance with the target machine specifications.
[0068] Thus, the machine language program for the target machine as
generated by the system according to the invention has features
mentioned below.
[0069] (1) Optimalization at the source program level as well as
optimalization of the register utilization is realized by the
compiler.
[0070] (2) Owing to the real register allocation function of the
installer, the registers incorporated in the target machine can be
made use of to a maximum extent.
[0071] (3) Owing to the instruction sequence pattern replacing
capability or function of the installer, it is possible to replace
a succession of plural ARM instructions by one instruction for the
target machine, to thereby make the most of a high performance of
the target machine. As a result of this, an object program can be
shared by a plurality of different machine type computers while
maintaining the execution speed and performance which are
equivalent to those involved in the execution of the machine
language program generated by the prior art system (prior rt
compiler system).
BRIEF DESCRIPTION OF THE DRAWINGS
[0072] FIG. 1 is a diagram showing schematically a general
arrangement of a translation system for translation of a source
program into a machine language program according to an embodiment
of the present invention;
[0073] FIG. 2 is a diagram showing schematically a structure of a
compiler for generating from a source program an abstract object
program in the form of a sequence of abstract register machine
instruction;
[0074] FIG. 3 is a diagram showing a relation between an abstract
register machine instruction sequence and a machine language
instruction sequence for a particular machine;
[0075] FIG. 4 is a view for illustrating types of generation
control statements contained in an abstract register machine
instruction;
[0076] FIG. 5 is a view for illustrating a format of an abstract
register machine instruction;
[0077] FIG. 6 is a view for illustrating relations between address
modes and operands in abstract register machine instructions;
[0078] FIG. 7 is a first part of a view showing specifications of a
machine language generation instruction contained in the abstract
register machine instruction;
[0079] FIG. 8 is a second part of the view showing specifications
of a machine language generation instruction contained in the
abstract register machine instruction;
[0080] FIG. 9 is a third part of the view showing specifications of
a machine language generation instruction contained in the abstract
register machine instruction;
[0081] FIG. 10 is a fourth part of the view showing specifications
of a machine language generation instruction contained in the
abstract register machine instruction;
[0082] FIG. 11 is a fifth part of the view showing specifications
of a machine language generation instruction contained in the
abstract register machine instruction;
[0083] FIG. 12 is a sixth part of the view showing specifications
of a machine language generation instruction contained in the
abstract register machine instruction;
[0084] FIG. 13 is a view for illustrating an example of the source
program which is inputted to the compiler shown in FIG. 2;
[0085] FIG. 14 is a first part of a view showing an example of the
abstract object program corresponding to the source program shown
in FIG. 13 in the state not optimalized yet;
[0086] FIG. 15 is a second part of the view showing an example of
the abstract object program corresponding to the source program
shown in FIG. 13 in the state not optimalized yet;
[0087] FIG. 16 is a third part of the view showing an example of
the abstract object program corresponding to the source program
shown in FIG. 13 in the state not optimalized yet;
[0088] FIG. 17 is a view for illustrating a process of calculating
priorities of register allocations in the abstract object program
shown in FIGS. 14 to 16;
[0089] FIG. 18 is a flow chart for illustrating a procedure for
generating priority bit vectors representing the priorities for the
register allocation in the compiler shown in FIG. 2;
[0090] FIG. 19 is a flow chart for illustrating a process of
eliminating a common expression as executed as a part of
optimization processing by the compiler shown in FIG. 2;
[0091] FIG. 20 is a first part of a view showing an example of the
abstract object program corresponding to the source program shown
in FIG. 13 for illustrating an abstract register machine
instruction sequence resulting from optimalization processing;
[0092] FIG. 21 is a second part of the view showing an example of
the abstract object program corresponding to the source program
shown in FIG. 13 for illustrating an abstract register machine
instruction sequence resulting from optimalization processing;
[0093] FIG. 22 is a flow chart illustrating a processing for
effectuating move of intra-loop invariants;
[0094] FIG. 23 is a view showing usages of physical registers in a
target machine A;
[0095] FIG. 24 is a view for illustrating correspondence relations
between the physical registers the abstract registers;
[0096] FIG. 25 is a flow chart for illustrating a translation into
a machine language with the aid of pattern matching technique;
[0097] FIG. 26 is a view showing a part of machine instruction
selecting rules oriented for the target machine A;
[0098] FIG. 27 is a view showing a state in which physical
registers in the target machine A are allocated to the abstract
object program shown in FIGS. 20 to 21;
[0099] FIG. 28 is a view showing a machine language program which
is generated from the abstract object program shown in FIGS. 20 and
21 by an installer for the target machine A;
[0100] FIG. 29 is a flow chart for illustrating processings
performed internally of the installer;
[0101] FIG. 30 is a schematic block diagram showing a structure of
the installer together with inputs and an output thereof;
[0102] FIG. 31 is a view showing usages of the physical registers
in a target machine B;
[0103] FIG. 32 is a view showing a state in which the physical
registers of the machine B are allocated to the abstract object
program shown in FIGS. 20 and 21;
[0104] FIG. 33 is a view showing a part of the machine instruction
selecting rules oriented for the machine B;
[0105] FIG. 34 is a view showing a state in which the physical
registers of the machine B are allocated to the abstract object
program shown in FIGS. 19 and 20;
[0106] FIG. 35 is a view showing an example of machine language
program generated by the installer for the machine B from the
abstract object program shown in FIGS. 19 and 20;
[0107] FIG. 36 is a block diagram showing a structure of debug
system to which the installer according to an embodiment of the
invention is applied;
[0108] FIG. 37 is a flow chart for illustrating operation of the
debugger;
[0109] FIG. 38 is a view showing an example of a display
command;
[0110] FIG. 39 is a flow chart for illustrating the display
processing;
[0111] FIG. 40 is a view showing an example of a break-point
setting command;
[0112] FIG. 41 is a flow chart for illustrating a break-point
setting processing;
[0113] FIG. 42 is a view showing an example of execution
command;
[0114] FIG. 43 is a flow chart for illustrating execution
processing and shows details of the processing in a step 5128 shown
in FIG. 37;
[0115] FIG. 44 is a view showing an example of the source program
which is subject to the debugging;
[0116] FIG. 45 is a view showing an example of a source/abstract
object/machine language correspondence table;
[0117] FIG. 46 is a block diagram showing a structure of an IC card
device incorporating an installer according to the invention;
[0118] FIG. 47 is a pictorial view showing an outer appearance of
an IC card system;
[0119] FIG. 48 is a top plan view of an IC card;
[0120] FIG. 49 is a flow chart for illustrating execution of an
abstract object program incorporated in the IC card;
[0121] FIG. 50 is a block diagram showing a system in which one and
the same abstract object program contained in an IC card is
executed by a plurality of IC card systems having different CPUs,
respectively;
[0122] FIG. 51 is a block diagram showing a system in which
abstract register machine code programs are shared by computer
systems of different machine types which are linked together
through a network; and
[0123] FIG. 52 is a block diagram illustrating, by way of example,
replacement of a computer system in which an abstract register
machine program is employed by another type of computer system.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0124] Now, the present invention will be described in detail in
conjunction with exemplary or preferred embodiments by reference to
the accompanying drawings.
[0125] FIG. 1 is a diagram showing an exemplary structure of a
translation system for translating a source program into a machine
language program, according to an embodiment of the present
invention.
[0126] The translation system includes three subsystems. They are a
compiler 1001, a linker 1002 and a installer 1003,
respectively.
[0127] When a source program 1004 is inputted to the compiler 1001,
the compiler 1001 performs a syntax analysis, a semantic analysis,
an optimalization processing (described hereinafter) and others on
the source program 1004, at the representation level of the source
program, to thereby output an ArmCode (Abstract register machine
code) program 1005 which is an abstract object program. At this
juncture, it should be noted that the ArmCode program is provided
according to one of the aspects of the present invention, and the
specifications of the ArmCode program will hereinafter be
elucidated in detail by reference to FIGS. 4 to 12. As to the
compiler 1001, a structure thereof will be described by referring
to FIG. 2, while the optimalization processing performed by the
compiler will be described later on in detail by reference to FIGS.
13 to 22.
[0128] The linker 1002 receives the ArmCode program 1005 generated
from the source program 1004 by the compiler 1001, another ArmCode
program 1007 generated similarly from another source program 1006
by the compiler 1001 and an ArmCode program library 1008, and
performs solution of problems concerning a relation between
routines referenced to by the programs and a relation between
variables or constants referenced to as well as integration of data
areas and that of instruction areas, as a result of which a linked
ArmCode program 1009 is outputted from the linker 1002.
Parenthetically, the function of the linker itself is equivalent to
a part of the function of the object program linkage editor known
heretofore if the ArmCode program is regarded as a conventional
machine language. Accordingly, any further description of the
linker 1002 will be unnecessary.
[0129] The installer 1003 is loaded with the linked ArmCode program
1009 to perform a real register allocation, selection or generation
of machine instructions and a machine-dependent optimalization with
the aid of register usage designation 1019 and machine instruction
generating rules 1020 which are contained in specifications
information 1010 of a target machine or computer A 1012 and then
the installer 1003 develops a machine language program 1011 on a
memory of the target machine A 1012. The processings carried out by
the installer also constitutes one of the aspects of the present
invention and will be described in detail later on by reference to
FIGS. 23 and 30. The computer or machine A 1012 executes the
machine language program 1011 developed in the manner as mentioned
above.
[0130] In case the ArmCode program 1014 generated from the source
program 1013 by the compiler 1001 requires no linkage with anyone
of ArmCode programs and the ArmCode program library 1008, as shown
in FIG. 1, the installer 1003 can be loaded with the ArmCode
program 1014 straightforwardly to thereby develop the same to a
corresponding machine language program.
[0131] The installer 1003 is destined for generating the machine
language program for the computer of the machine type A hereinafter
referred to as the machine A. On the other hand, another installer
1015 serves to generate a machine language program 1016 for a
machine B 1017 by using specifications information 1018 of the
target machine B. In this manner, the translation system now
according to the present invention is capable of generating from
the same linked ArmCode program 1009 or the single ArmCode program
1014 a plurality of machine language programs such as exemplified
by the machine language programs 1011 and 1016 for a plurality of
target machines such as exemplified by the computers A 1012 and B
1017 to thereby allow these target machines to execute the relevant
programs, respectively. As will be appreciated from the above
description, the translation system according to the invention can
generate from the same ArmCode program a plurality of machine
language programs for a plurality of target machines or computers
of the specifications differing from one another, an example of
which will hereinafter be described in more detail by reference to
FIGS. 31 to 35.
[0132] FIG. 2 is a diagram showing an exemplary structure of an
abstract register machine compiler (generally denoted by 3100)
according to the embodiment of the present invention. Referring to
the figure, a source program 3102 undergoes at first a syntax
analysis and a semantic analysis by a syntax/semantic analysis
section 3104 of the compiler 3100 to be translated into an
intermediate language program 3106, while information of a variety
of symbols used in the source program 3102 is entered in a symbol
table 3108. An intermediate language optimalization section 3110 of
the compiler 3100 performs a control flow analysis and a data flow
analysis on the intermediate language program 3106 to thereby
realize a global optimalization, as a result of which there is
generated an ArmCode program 3112 as a sequence of abstract
register machine code instructions prior to an optimalization
processing 3114. Subsequently, the optimalization processing 3114
on the ArmCode program is carried out to generate an abstract
object program 3116 as the optimalized ArmCode-R instruction
sequence. Concerning the methods of the syntax analysis, the
semantic analysis, the control flow analysis, the data flow
analysis and the global optimalization, reference may be made to
"A. V. Aho, R. Sethi and J. D. Ullman: Compilers; Principles,
Techniques and Tools", Addison-Wesley Publishing Co., 1986, pp.
1-24.
[0133] One of the aspects of the present invention can be seen in a
structure of the abstract register machine code ArmCode
instruction. In other words, this ArmCode instruction has a
structure and contents which are suited for the processings
contemplated by the present invention, i.e., a high speed
translation of the abstract object program to a machine language
program suited for the target machine upon loading of the abstract
object program. A system of the ArmCode instructions is common to a
number of reduced instruction set computers (RISC) machines and it
will hereinafter be referred to as the ArmCode-R (Abstract register
machine Codes for RISC machines) system.
[0134] The ArmCode-R instructions are suited for the computers
having the features mentioned below.
[0135] (1) Operations are performed only between or among the
registers.
[0136] (2) Memory access is made only with the load/store type
instruction.
[0137] (3) A base register is incorporated.
[0138] (4) Registers which can be employed for operations are not a
few (sixteen or more).
[0139] (5) Immediate constants are available.
[0140] (6) All the instructions can each be represented by one word
(32 bits).
[0141] Each of the ArmCode-R instructions is not the very machine
instruction for a specific target computer but can easily be
translated to the machine instruction. The representation format of
each ArmCode-R instruction is characterized by the features
mentioned below.
[0142] (1) The register is not represented as a physical register
but as a abstract register.
[0143] (2) A memory address is specified based on not a numerical
value address but a symbol name.
[0144] (3) The memory is addressed on a byte basis.
[0145] (4) The instruction is of a fixed length.
[0146] In the following description, it should be understood that
the expression "ArmCode" represents "ArmCode-R" unless specified
otherwise.
[0147] FIG. 3 is a diagram for illustrating correspondence
relations between the ArmCode program and the machine language
program for the target machine shown in FIG. 1. As mentioned
previously, the source program 2910 undergoes the translation and
linkage processing through a compiler/linker section 2912 to be
translated into an abstract object program 2920, which is
represented by an ArmCode instructions sequence composed of
instructions for the abstract register machine.
[0148] Each ArmCode instruction is similar to one for a model
machine or computer common to many of the currently used computers,
and include an abstract operator 2921, an abstract register
designation 2923 and an abstract memory/constant designation 2925
as typical or representative items. The abstract operator
represents the content of one of instructions incorporated
universally in many computers, such as load/store for instructing
data transfers between a memory and a register, an arithmetic
operation as addition or subtraction and others. The abstract
register name designation indicates a register in the abstract
register machine, wherein no limitation is imposed to the number of
the abstract registers, differing from a case of a real computer.
The abstract memory/constant designation 2925 can be handled
similarly to that for an memory address and a constant in the real
computer except that the former is free from any limitation in
respect to the address and magnitudes of a value of the
constant.
[0149] The ArmCode instruction sequence 2920 is translated into a
machine language instruction sequence for a target machine through
the installer provided in association with the target machine. By
way of example, the instruction sequence 2920 shown in FIG. 3 is
translated into a machine language instruction sequence 2950 for a
machine A when an installer 2930 for the machine type A is used
while it is translated into a machine language instruction sequence
2960 for a target machine B when an installer 2940 for the target
machine B is used. The ArmCode instructions and real machine
instructions are not always in one-to-one correspondence. In
general terms, an instruction sequence including m ArmCode
instructions is translated into an instruction sequence including n
real machine instructions. An operator, a register designation and
a memory/constant designation contained in each machine instruction
are inherent to the machine to which that machine instruction is
oriented. For example, an operator 2951, a register designation
2953 and a memory/constant designation 2955 of each machine
instruction of the machine language program 2950 oriented for the
machine A are inherent to that machine A, while an operator 2961, a
register designation 2963 and a memory/constant designation 2965 of
each machine instruction contained in the machine language program
2960 for the machine B are inherent to that machine B.
[0150] In the ArmCode instruction there are contained machine
instruction generating instructions describing instructions which
are actually to be executed by the target computer and structures
thereof as well as generation control statements for controlling
the generation of machine instructions, as exemplified below:
[0151] alloc(Ar10,RcArith,alc10,5,0,0,xc0000000);
[0152] if (alc10)
[0153] Load RegMd Ar10 Vbase OdDisp v;
[0154] Add RegCon Ar11 Noreg OdCi 6;
[0155] As the machine instruction generating instructions, there
may be mentioned the following types, which are written in an array
in the abstract object program, being punctuated by semicolons.
[0156] (1) Corresponding machine language instructions:
[0157] (Load4, Store4, Add, Sub, etc.)
[0158] (2) Pseudo-instructions representing program structures:
[0159] (Start/Pend, Block/End, Stmt, etc.)
[0160] (3) Pseudo-instructions for indicating the symbol names:
[0161] (Entry, External, Label, Name, etc.)
[0162] (4) Pseudo-instructions for designating the memory:
[0163] (Dword, Dconst, Daddr, etc.)
[0164] (5) Pseudo-instructions for designating the symbol
information oriented for a debugger or the like:
[0165] (Sinf, etc.)
[0166] As is shown in FIG. 4, the generation control statement
includes a conditional statement 3120, an assignment statement 3122
and a function reference statement 3124 and equations containing
constants and simple variables can be used in the statements. As
generation control functions, there can be used those functions
mentioned below (refer to 3124 in FIG. 4).
[0167] (1) Function: "alloc" (abstract register name, register
type, discriminant variable, instruction number, preserve count,
priority)
[0168] This function "alloc" serves for requesting allocation to an
abstract register designated by a first parameter a physical
register of the type designated by a second parameter. The
instruction number is an ordinal number identifying an abstract
register using instruction in precedence to the allocation request.
The preserve count represents the number of the registers to be
preserved even after the register allocation. The priority
represents the level of priority at which the register is to be
allocated. The value of the discriminant variable designated by a
third parameter is set to "1" when a physical register can be
allocated at the time of the register allocation request while it
is set to "0" when allocation of the physical register is
impossible.
[0169] (2) Function: free (abstract register name)
[0170] This function serves for making free (deallocating) the
physical register from the abstract register designated by the
first parameter.
[0171] The priority for the register allocation is represented by a
bit vector. The abstract register using instructions are assigned
with the sequential instruction numbers, the abstract register to
be used after p instructions as counted from the current
instruction is correspondingly assigned with a bit vector including
one bit of "1" placed after a succession of "0s" in a number of
(p-1). The priority is decided by regarding the bit vector as an
unsigned integral value such that the unsigned integral value of
greater magnitude represents a higher priority. Accordingly, the
priority of the abstract register to be used immediately is higher
than that of the abstract register used subsequently. For the
abstract register to be used at a plurality of instructions, a bit
vector resulting from the OR operation of those corresponding to
the plural instructions is assigned. Whenever progress is made from
the current instruction, the bit vector is shifted to the left by
one bit. The leftmost overflowed bit occurring upon shifting to the
left is discarded with the rightmost bit being supplemented with
"0". Accordingly, the priority of an abstract register becomes
highest immediately before the use of that abstract register and is
lowered after having passed the instruction where the abstract
register is used.
[0172] The bit vector representing the priority is not restricted
to such structure in which the bit "1" is assigned to one
instruction. By way of example, an abstract register using
instruction sequence may be segmentalized into segments each of a
fixed length, and the segments are assigned with bits in one-to-one
correspondence such that the bit is set to the value "1" when an
abstract register of concern is used in the segment to which the
abovementioned bit is assigned while otherwise being set to "0". In
this manner, it is possible to express with a bit vector of a
shorter length the using state of a register in the long
instruction sequence. By setting the length of the segment to "1"
(unity), the correspondence relation described above can be
realized.
[0173] In the case of an abstract register used through or in a
loop, it is assumed that the register is used again or repetitively
at an interval corresponding to a length of the loop (or
one-severalth of the length of the loop), and an original bit
vector is shifted to the right by an adjust count corresponding to
the loop length (or one-severalth thereof) and the shifted bit
vector is arithmetically added to the original bit vector. A
resulting sum is used as the bit vector representing the priority
of the abovementioned register.
[0174] With the function "alloc" for allocating the physical
registers to the abstract registers, the priorities mentioned above
are designated. The allocation is performed when the number of the
physical registers capable of accommodating the abstract registers
having the designated priorities are available, while otherwise the
allocation is not performed. The priority allocated previously to
an abstract register becomes higher as the instruction which the
register is used becomes closer while the former becomes lower
beyond the instruction using that register. Thus, performance of
the allocation can be determined by comparing the priority of a
register with the priorities of the other registers. Overflowed
abstract registers not allocated with the physical registers
because of their low priorities are allocated to the memory areas.
Concerning the priority, description in detail will be hereinafter
be made by reference to FIG. 9.
[0175] FIG. 5A is a view for illustrating a format of the ArmCode-R
instruction. As can be seen in this figure, each of the ArmCode-R
instructions 3130 is composed of fields of an operator 3132, an
address mode 3134, a first operand 3136, a second operand 3138 and
a third operand 3140, respectively, which have the contents
mentioned below.
[0176] Operator: name of the ArmCode-R instruction.
[0177] Address mode: discrimination of operand form.
[0178] 1st operand: register R1, literal c1 or ArmCode address
c1.
[0179] 2nd operand: register R2, literal c2 or ArmCode address
c2.
[0180] 3rd operand: memory address, displacement d3, literal c3,
label c3, ArmCode address c3, etc.
[0181] As shown in FIG. 5B, the operands 3136, 3138 and 3140 are
expressed as follows (refer to specifications of the machine
language instruction generating instruction):
[0182] Register: abstract register number.
[0183] Memory Address: absolute address, position of a variable
name in a symbol table or abstract register number representing an
address in the memory.
[0184] Displacement: numerical value representing displacement
relative to a base register.
[0185] Literal: integer constant (numerical values, character code
or positions of a character string table and a comment table to be
subjected to operation).
[0186] Label: item number of a label table LBL.
[0187] ArmCode Address: position of instruction ArmCode
[0188] The third operand is expressed in terms of a combination of
a sub-item indicating type of the operand and a sub-item indicating
the operand, as follows.
[0189] 0dsym s3: symbol table entry item s3.
[0190] 0dLab c3: label table (LBL) entry c3.
[0191] 0dci c3: intra-instruction scalar constant c3.
[0192] 0dCL c3: Intra-memory scalar constant indicated by c3.
[0193] 0dCS c3: string constant c3.
[0194] 0dGvar s3: temporal variable s3 generated by the
compiler.
[0195] 0dDisp c3: displacement c3
[0196] 0dNo Null: indication of absence of the third operand.
[0197] The first operand 3136 indicates a store destination
position of the execution result in the case of the instruction for
a loading operation and an computing operation while it indicates a
register which holds the data to be stored in the case of the
instruction for a storing operation. In the case of a conditional
branch instruction, the first operand 3136 indicates a register
holding target data for the condition determination. The address
mode 3134 indicates the number of valid operands and the roles of
them.
[0198] FIG. 6 is a view for illustrating possible combinations of
the address mode 3134 with the first operand (operand 1) 3136, the
second operand (operand 2) 3138 and the third operand (operand 3)
3140 shown in FIG. 5. It can be seen from FIG. 6 what roles the
operand 1 3172, operand 2 3174 and the operand 3 3176 play for each
of the address modes 3170 such as RegReg, RegMI and others. In FIG.
6, blank column indicate that the relevant operands are not valid.
When the operand is a simple register, the value of the register is
utilized. When the operand represents a constant, the value thereof
is utilized or set. When the operand represents an address
register, the content of that address register is regarded as a
memory address to be accessed. In case the operand designates the
base register and a displacement, a value resulting from addition
of the content of the base register and the displacement is
regarded to be a memory address upon making access to that operand.
In the address mode RegRCC, the constants c3 and c4 are regarded to
be positive integers not greater than "255" and nested in the third
operand.
[0199] FIGS. 7 to 12 are views showing specifications of the
machine instruction generating instruction. Meanings of the symbols
used in the specifications are as follows.
[0200] a: address or constant a. When this value represents the
address, a may be a numerical value c indicating the absolute
address or a numerical value s indicating a position of the symbol
table.
[0201] [a]: content of the register or memory at the address a.
[0202] a : register or memory pointed by the content of the address
a (having the address given by the content of a).
[0203] ( ): parenthesized expression is handled as one symbol.
[0204] .fwdarw.: assigning to right-hand register or variable.
[0205] .rarw.: assigning to left-hand register or variable.
[0206] In the case of the instant embodiment of the present
invention, there are used the instructions mentioned below.
[0207] 1) Load instructions 3210 (FIG. 7)
[0208] Load: Load one word data indicated by the operand 2 or 3 in
the register indicated by the operand 1.
[0209] LoadB: Load one-byte data indicated by the operand 2 or 3 in
the register indicated by the operand 1 with right
justification.
[0210] Mode-wise processings:
[0211] RegReg: R1.rarw.[R2]
[0212] RegMI: R1.rarw.[R2]
[0213] RegMR: R1.rarw.[([R2]+d) ]
[0214] RegMD: R1.rarw.[d]
[0215] RegCon: R1.rarw.c3
[0216] RegAdr: R1.rarw.[R2]+d
[0217] 2) Store instructions 3220 (FIG. 7)
[0218] Store: Store one-word data of the operand 1 in a location
indicated by the operand 2 or 3.
[0219] StoreB: Store the rightmost one byte data of the operand 1
in a location indicated by the operand 2 or 3.
[0220] Mode-wise processings:
[0221] RegReg: [R1].fwdarw.R2
[0222] RegMI: [R1].fwdarw.R2
[0223] RegMR: [R1].fwdarw.([R2]+d)
[0224] RegMD: [R1].fwdarw.d
[0225] 3) Integer-class binary floating point instructions 3230
(FIG. 7)
[0226] Add: Add the operand 2 to the operand 1, and place the
result of the addition in the operand 1. Set a carry of "1" or "0"
in dependence on presence or absence of overflow.
[0227] Sub: Subtract the operand 2 from the operand 1, and place
the result of the subtraction in the operand 1. Set a carry to "1"
when the operand 2 is greater than the operand 1 and otherwise to
"0".
[0228] Mult: Multiply the operand 1 by the operand 2, and place the
result of the multiplication in the operand 1.
[0229] Div: Divide the operand 1 by the operand 2, and place the
quotient in the operand 1.
[0230] UnsAdd: Same as the instruction Add except for unsigned
addition.
[0231] UnsSub: Same as the instruction Sub except for unsigned
substruction.
[0232] AddC: Same as the instruction Add except that the carry is
considered in the addition.
[0233] SubB: Same as the instruction Sub except that the borrow is
considered in the subtraction.
[0234] Mode-wise processings:
[0235] RegReg: ([R1] op [R2]).fwdarw.R1
[0236] RegCon: ([R1] op c3).fwdarw.R1
[0237] where "op" represents an operator.
[0238] 4) Real number-class binary floating point instructions 3240
(FIG. 8)
[0239] AddR: Add the operand 2 to the operand 1, and place the
result of the addition in the operand 1.
[0240] SubR: Subtract the operand 2 from the operand 1, and place
the result of the subtraction in the operand 1.
[0241] MultR: Multiply the operand 1 by the operand 2, and place
the result of the multiplication in the operand 1.
[0242] DivR: Divide the operand 1 by the operand 2, and place the
quotient in the operand 1.
[0243] Mode-wise processings:
[0244] RegReg: ([R1] op [R2]).fwdarw.R1
[0245] RegCon: ([R1] op c3).fwdarw.R1
[0246] where "op" represents an operator.
[0247] 5) Binary logical instructions 3250 (FIG. 8)
[0248] And: Execute an AND operation of the operand 1 and the
operand 2 and place the result of the AND operation in the operand
1.
[0249] Or: Execute an OR operation of the operand 1 and the operand
2, and place the result of the OR operation in the operand 1.
[0250] Xor: Execute an XOR or exclusive OR operation of the operand
1 and the operand 2, and place the result of the XOR operation in
the operand 1.
[0251] Mode-wise processings:
[0252] RegReg: ([R1] op [R2]).fwdarw.R1
[0253] RegCon: ([R1] op c3).fwdarw.R1
[0254] where "op" represents an operator.
[0255] 6) Unary instructions 3260 (FIG. 8)
[0256] Negate: Invert the sign of the operand 1, and place the
result of inversion in the operand 1.
[0257] Not: Invert the bits of the operand 1, and place result of
inversion in the operand 1.
[0258] Mode-wise processing:
[0259] Reg1: Computation is performed on the content of the operand
1, the result of which is left in the operand 1.
[0260] 7) Comparison instruction 3270 (FIG. 8)
[0261] Compar: Compare the content of the operand 1 with that of
the operand 2 and set a condition code.
[0262] Mode-wise processings:
[0263] RegReg: If [R1]>[R2] then Gt, if [R1]=[R2] then Eq, if
[R1]<[R2] then Lt.
[0264] RegCon: If [R1]>c3 then Gt, if [R1]=c3 then Eq, if
[R1]<c3 then Lt.
[0265] 8) Condition test instructions 3280 (FIG. 8)
[0266] TZero mode Reg1: If "0", set the condition code to "Eq" and
otherwise to "Ne".
[0267] TBit mode RegCon: When the bit of [R1] at a position
indicated by c3 of the third operand is "0", set the condition code
to "Eq", while when it is "1", set the condition code to "Ne".
[0268] 9) Conditional branch instructions 3290 (FIG. 9)
[0269] BrEq: When the condition code is "Eq", jump to a position
indicated by the operand.
[0270] BrNe: Unless the condition code is "Eq", jump to a position
indicated by the operand.
[0271] BrGt: When the condition code is "Gt", jump to a position
indicated by the operand.
[0272] BrGe: When the condition code is "Gt" or "Eq", jump to a
position indicated by the operand.
[0273] BrLe: When the condition code is "Lt" or "Eq", jump to a
position indicated by the operand.
[0274] BrLt: When the condition code is "Lt", jump to a position
indicated by the operand.
[0275] In any of the cases mentioned above, the control is made to
an immediately succeeding instruction unless the condition is
met.
[0276] Mode-wise processings:
[0277] Const: Position indicated by the label table LBL[c3] is the
address of the jump destination.
[0278] RegR: [R2]+d is the address of the jump destination.
[0279] 10) Unconditional branch instruction 3300 (FIG. 9)
[0280] Jump: Jump to a position indicated by the operand.
[0281] Mode-wise processings:
[0282] Const: Position indicated by the label table LBL[c3] is the
address of the jump destination.
[0283] RegR: [R2]+d is the address of the jump destination
[0284] 11) Subprogram reference instruction 3310 (FIG. 9)
[0285] Call: After recording a return address, jump to a subprogram
indicated by the operand.
[0286] Mode-wise processings:
[0287] RegMR: Placing the return address in R1, jump is made to the
address [R2]+d.
[0288] RegMD: Placing the return address in R1, jump is made to a
subprogram address indicated by the label table LBL[c3].
[0289] Reg1: After stacking the return address, jump to the address
[R1].
[0290] 12) Return instruction 3320 (FIG. 9)
[0291] Return: Jump to the return address recorded by the
instruction "Call" from the subprogram indicated by the
operand.
[0292] Mode-wise processings:
[0293] Reg1: Jump to the return address recorded in R1.
[0294] Reg0: Fetching of the return address stacked by the
instruction "Call" through LIFO scheme and jump to the fetched
return address.
[0295] 13) Shift instructions 3330 (FIG. 10)
[0296] These instructions are each to shift the content of the
first operand R1 to the left or right by a bit number n indicated
by the second or third operand.
[0297] ShiftL: Shift R1 to the left by n bits with the rightmost n
bits being "0s".
[0298] Shift R: Shift R1 to the right by n bits with the leftmost n
bits being "0s".
[0299] Mode-wise processings:
[0300] RegCon: R1 represents a target register (i.e. register of
concern) with c3 representing the bit number for the shift.
[0301] RegReg: R1 represents a target register with [R2]
representing the bit number for the shift.
[0302] 14) Rotation instructions 3340 (FIG. 10)
[0303] These instructions are each to rotate the content of the
first operand R1 to the left or to the right by a number n of bits
indicated by the second or third operand.
[0304] RotL: Rotate R1 to the left by n bits.
[0305] RotR: Rotate R1 to the right by n bits.
[0306] Mode-wise processings:
[0307] RegCon: R1 represents a target register with c3 representing
the bit number for the rotation.
[0308] RegReg: R1 represents a target register with [R2]
representing the bit number for the rotation.
[0309] 15) Bit manipulation instructions 3350 (FIG. 10)
[0310] GetBit RegCC: Place the c3-bit data starting from the bit c2
of R1 in R1 with right justification. Left-hand bit portion of R1
is "0".
[0311] GetBit RegRCC: Place the c3-bit data starting from the bit
c2 of R2 in R1 with right justification. Left-hand bit portion of
R1 is "0".
[0312] PutBit RegRCC: Place the rightmost c4-bit data of R1 in a
c4-bit length field starting from the bit c3 of R2. Content of
other bit field remains unchanged.
[0313] 16) Data conversion instructions 3360 (FIG. 10)
[0314] ItoR RegReg: Instruction for integer-to-real conversion of
the content of R1, the result being placed in R2.
[0315] RtoI RegReg: Instruction for real-to-integer conversion of
the content of R1, the result being placed in R2.
[0316] ItoD RegReg: Instruction for integer-to-double real
conversion of the content of R1, the result being placed in R2.
[0317] DtoI RegReg: Instruction for double real-to-integer
conversion of the content of R1, the result being placed in R2.
[0318] 17) Status switch instructions 3370 (FIG. 11)
[0319] SaveSt RegMR: Save the current processor status in the
memory. (saving information: program counter, status code, mask,
etc.)
[0320] LoadSt RegMR: Restore the processor status in accordance
with information stored in the memory.
[0321] 18) No-operation instruction 3380 (FIG. 11)
[0322] Nop Reg0: No execution of operation with a machine
instruction occupying one word.
[0323] 19) Program structure representing pseudo-instructions 3390
(FIG. 11)
[0324] Start Cont1 0dSym: Pseudo-instruction for starting object
having a name (of the symbol table) indicated by s3.
[0325] SubP Cont1 0dSym: Pseudo-instruction indicating the start of
a subprogram indicated by s3.
[0326] Block Cont0: Block start pseudo-instruction.
[0327] End Cont0: Block end pseudo-instruction.
[0328] Loops Cont1 0dLab: Pseudo-instruction indicating a head of a
loop statement having a label indicated by LBL (c3) as a repetition
starting point.
[0329] Loope Cont1 0dLab: Pseudo-instruction indicating trail of a
loop statement having a label indicated by LBL (c3) as a repetition
starting point.
[0330] Pend Cont0: End of a subprogram or unit. (This "End"
instruction is followed by "Define Storage" and "Define Constant"
instructions and finally by "Pend" instruction.)
[0331] Stmt Cont1 0dCi: Pseudo-instruction indicating a start
position of a statement having c3 as the statement number.
[0332] 20) Symbol name indicating pseudo-instructions 3400 (FIG.
11)
[0333] Entry Cont1 0dSym: Pseudo-instruction indicating a name (of
the symbol table) indicated by s3 as an entry name.
[0334] Extern Cont1 0dSym: Pseudo-instruction indicating that a
name (of symbol table) indicated by s3 is an external name.
[0335] Label Cont1 0dLab: When c3 represents a LBL table number
(user label) having a symbol table, the pseudo-instruction defining
the name of the symbol table as the table name. When c3 represents
a LBL table number (generated label) having no symbol table, this
pseudo-instruction defining the generated label name 536 n as the
label name.
[0336] Label cont1 0dCL: Pseudo-instruction defining a constant
name .Yen..Yen.Cm as the label name, when c3 is LRG table number m
representing a memory constant.
[0337] Label Cont1 0dGvar: Pseudo-instruction defining a generated
variable name .Yen..Yen.Tk as the label name, when s3 is symbol
table number k representing a generated variable.
[0338] Name Cont1 0dSym: Pseudo-instruction equating a name (of
symbol table) indicated by s3 to the name of immediately preceding
OpLabel.
[0339] 21) Memory designating pseudo-instructions 3410 (FIG.
12)
[0340] Dconst Cont1 0dCi: Constant definition for defining c3 as an
integer constant value.
[0341] Dconst Cont1 0dCS: Constant definition for regarding c3 as a
one-word character string.
[0342] Dconst Cont1 0dCS: Constant definition for regarding c3 as a
one-word character string constant.
[0343] Dword Cont1 0dCi: "Define Storage" pseudo-instruction for
securing a memory area of c3 words.
[0344] Daddr Cont1 0dSym: "Define Address" pseudo-instruction for
the name (of symbol table) indicated by s3.
[0345] MCode Cont1 0dCi: Pseudo-instruction for generating a
machine language MRT[c3] indicated by c3.
[0346] 22) Pseudo-instructions 3420 designating debugger-oriented
symbol information, etc. (FIG. 12)
[0347] PInf Cont1 0dCi: Pseudo-instruction indicating information
of a program characteristic information table resident at a
position indicated by c3.
[0348] SInf Cont1 0dCi: Pseudo-instruction indicating symbol
information at a position indicated by c3.
[0349] FIG. 13 is a view showing an example of the source program
3102 which is inputted to the compiler 3100 shown in FIG. 2. The
source program 3102 is composed of a declaration statement 3610
designating a global variable, designation of a name of a function
3614, a declaration statement 3616 of local variables in the
function, a sequence of executable statements beginning with an
executable statement 3620, etc. The numbers such as "1" positioned
at the head of the declaration statement 3610, "10" at the head of
the executable statement 3620 and the like represent the
identification numbers of the respective statements. FIGS. 14 to 16
show in combination an example of the ArmCode instruction sequence
resulting from the translation of the source program shown in FIG.
13. The illustrated instruction sequence is not yet subjected to
the optimalization processing. A pseudo-instruction 3700
designating symbol information in FIG. 14 corresponds to the
declaration statement 3610 in the source program shown in FIG. 13.
Similarly, a pseudo-instruction 3702 corresponds to the declaration
statement 3616. Further, an ArmCode instruction sequence beginning
with the executable statement 3710 shown in FIG. 14 corresponds to
the sequence of executable statement beginning with the statement
3620 of the source program shown in FIG. 13.
[0350] Now, description will be made in more concrete concerning
the priorities of the registers with reference to FIG. 14 to FIG.
18. The instructions which use abstract registers in this ArmCode
program are 3720, 3722 and so forth with an asterisk "*" at the
head. The instruction "alloc" 3710 requests the allocation of a
physical register to an abstract register named "Vbase" with the
priority designated as "0x62489700+0x00224897". The abstract
register named Vbase is used by the instructions 3722, 3734, 3758,
3770, 3790, 3828, 3846, 3850, 3856 and 3860. 32 instructions from
the instruction "alloc" 3710 are checked to determine whether or
not these are an abstract register using instruction. Based on the
checked result, a bit vector is generated in which "1s" are placed
at the bit positions corresponding to the instructions which use
the abstract register Vbase while "0s" are placed at the positions
of the instructions which do not use the abstract register. As a
result, the bit vector is represented by
"01100010010010001001011100000000", which can be rewritten as
"0x62489700" in the hexadecimal notation, as is shown in the
instruction "alloc" 3710. In the case of the program shown in FIGS.
14 to 16, there exists a loop from the instruction 3868 to the
instruction 3728. This loop includes 23 instructions which use the
abstract register. In the case of the instant embodiment, the
number of the instructions using the abstract register and
contained in this loop is divided by "3", and a value associated
with the quotient when the remainder is "0" or (the quotient +1)
when the remainder is not zero is defined as the adjust number. The
bit vector of the abstract register "Vbase" used in the loop is
represented by setting the second bit to "0" in the bit vector
3910, i.e. "00100010010010001001011100000000". By shifting this bit
vector to the right by a number "8" resulting from division of "23"
by "3" with the remainder being rounded up, there is obtained
"00000000001000100100100010- 010111", as shown in conjunction with
the instruction 3912, which is represented by "0x00224897" in the
hexadecimal notation. Accordingly, the priority of the "Vbase"
allocation request is represented by a number
"0x62489700+0x00224897", i.e., a sum of the addition of
"0x62489700" and "0x00224897" as unsigned integers, as shown in the
instruction "alloc" 3710 in FIG. 14. Through a similar procedure,
the priority for the abstract register Ar5 can be computed, as is
shown at 3918 and 3920 in FIG. 17.
[0351] The register allocation priority is not fixed but shifted to
the left as the instructions are checked, as described previously.
For example, at the position of the instruction 3732 located at the
head of the loop which follows after the two register using
instructions, the priorities of the registers "Vbase" and "Ar5" are
shifted by two bits, respectively, resulting in that the priority
of the register "Vbase" is "0x89225C00+0x0089225C", as shown at
3914 and 3916 in FIG. 17, while that of the register "Ar5" is
"0x44110000+0x00441100", as shown at 3922 and 3924. This priority
is compared with the priority "0xE0000000" of the register "Ar6"
whose allocation is requested by the instruction 3732.
[0352] FIG. 18 is a flow chart for illustrating a procedure for
generating the priority bit vector in the register allocation
mentioned above. The priority bit vector of a register r is assumed
to be represented by Pr. This bit vector Pr is first reset (step
3930). A succeeding ArmCode instruction is fetched (step 3932) and
checked whether it is the loop start instruction (step 3934). When
it is not the loop start instruction, then it is checked whether
the fetched ArmCode instruction is the register using instruction
(step 3936). When the answer of this decision step 3936 is
affirmative (Y), the priority bit vector Pr of the register r is
shifted to the left by one bit (step 3938). Subsequently, it is
checked whether or not the register r is use (step 3940). When the
register r is used, "1" is set at the rightmost bit of the priority
bit vector Pr (step 3942). If otherwise (N), the rightmost bit of
the bit vector Pr is set to "0" (step 3943). When the succeeding
ArmCode instruction is a loop exit instruction or an instruction to
free the register r, computation of the priority bit vector for the
register r comes to an end (step 3944). If otherwise, the next
ArmCode instruction is fetched, and the processing described above
is repeated.
[0353] When the ArmCode instruction as fetched in the step 3932 is
determined to be the loop start instruction (step 3934), the
priority bit vector of the register r is assumed to be represented
by Lr within the loop under consideration and determined through
the same procedure as described above (steps 3930 to 3944).
Subsequently, the number of the abstract register using
instructions contained in the loop is divided by three with the
remainder. If there is any remainder, the quotient is rounded up.
Then, the priority bit vector Lr is adjusted by shifting it to the
right by a number of bits corresponding to the quotient or the
rounded up quotient resulting from the above determination (step
3947). There after, the adjusted priority bit vector Lr is added to
the priority bit vector Pr of the instruction sequence including
the loop (step 3948). In this way, the allocation priority bit
vector Pr for one abstract register r can be computed. This
processing is executed for each of the abstract registers.
[0354] FIG. 19 is a flow chart illustrating a procedure of the
object optimization for enhancing the efficiency of execution of a
machine language program obtained from an ArmCode program according
to an embodiment of the present invention. At first, an ArmCode
instruction sequence of the ArmCode program is divided into a
plurality of basic blocks by punctuating the sequence at flow-in
points and branching points of the control (step 3952). Each of the
basic blocks has a feature that it is executed in a beeline from
the start to last instructions. In the case of the example
illustrated in FIGS. 14 to 16, the instructions 3712 to 3722, 3724
to 3748, 3750 to 3778 etc. constitute the basic blocks,
respectively, and a generation control instruction "bblock"
indicating the inter-block link relation is added at the head. In
the case where a certain basic block b is necessarily executed
immediately after the execution of other basic block a, a basic
block sequence which allows execution of the block b in succession
to the basic block a to which the block b is linked is referred to
as the extended basic block. By way of example, for the basic
blocks starting from the instructions 3724, 3750 and 3780,
respectively, a resultant block obtained by linking together these
three basic blocks represents an extended basic block, because in
each of the abovementioned basic blocks, the succeeding instruction
is neccessarily executed immediately after the preceding
instruction. The basic block beginning with the instruction 3840,
for example, where extension is impossible because the preceding
basic block and the succeeding basic block can not definitely be
established, is defined by itself as one extended basic block.
Subsequently, a common expression or equation in the extended basic
block is deleted. To this end, starting from the first extended
basic block (step 3954), the common equation in the extended basic
blocks is picked out (step 3956). The succeeding common equation is
replaced by the content of a register or a variable representing
the result of the common equation picked out precedingly (step
3958). This procedure is repeated until the last extended basic
block has been reached (steps 3960, 3962). The abovementioned
processing can be carried out by applying the algorithm disclosed
in the Aho, Sethi and Ullman mentioned hereinbefore to the ArmCode
instruction sequence.
[0355] FIGS. 20 to 21 are views showing in combination an ArmCode
instruction sequence generated as the result of the above-mentioned
processing of the instruction sequence shown in FIGS. 14 to 16 and
the optimalization processing described below. Referring to FIGS.
20 and 21 together with FIGS. 14 to 16, the optimalization
processing will now be elucidated in concrete. In FIGS. 14 to 16,
the computation instructions 3758 and 3760 for computing the value
of the abstract register Ar8, the computation instructions 3790 and
3792 for computing the value of the abstract register Ar12 and the
computation instructions 3828 and 3830 for computing the value of
abstract register Ar15 are same as the computation instructions
3734 and 3736 for determining the value of the abstract register
Ar6, while the instruction 3764 for determining the value of the
abstract register Ar9 is same as the instruction 3740 for
determining the value of the abstract register Ar7. Similarly, the
instruction for determining the register value Ar13 is same as that
for the register value Ar11, while the instructions for determining
the register values Ar15 and Ar16 are same as that for determining
the value of Ar5. Consequently, in the instruction 4098, the
abstract registers Ar6 and Ar11 are reused, while in the
instruction 4076, the register Ar7 is reused with the register Ar5
being reused in the instructions 4108, 4110 and 4112, as shown in
FIGS. 20 and 21. In this manner, these abstract registers are
replaced by those having the identical values, respectively,
whereby the instructions for determining the values of the abstract
registers Ar8, Ar12, Ar15, Ar9, Ar13, Ar15 and Ar16 are deleted.
Since the use frequencies of the abstract registers as well as the
positions at which they are used change in accompanying the
replacements mentioned above, the order of the priorities allocated
to these abstract registers will vary correspondingly. The
instructions "alloc" 4028 etc. shown in FIGS. 20 and 21 indicate
the processings mentioned above.
[0356] An ArmCode program shown in FIGS. 20 and 21 is derived from
the ArmCode program shown in FIGS. 14 to 16 by moving the
intra-loop invariant equation outside of the loop and by effecting
a branch optimalization. FIG. 22 is a Flow chart for illustrating
the processing to this end. More specifically, referring to the
figure, the loops are detected by a flow analysis (step 4202).
Thereafter, starting from the innermost loop (step 4204), the
intra-loop invariant equations are detected (step 4206) to be
subsequently moved to the position immediately before the start of
the loop (step 4208), evading repetition of the same computation
within the loop. This processing is repetitively executed up to the
outermost loop inclusive (steps 4210, 4212). Since the values of
the abstract registers Ar10, Ar11 and Ar17 shown in FIGS. 14 to 16
remain invariable in the loop which starts from the instruction
3728 and ending at the instruction 3874, the instructions 3770,
3786 and 3860 for computing the values of these registers are moved
to the position before the loop. The instructions moved in this way
are indicated at 4038, 4044 and 4050, respectively, in FIGS. 20 and
21.
[0357] Further, referring to FIGS. 14 to 16, the branch destination
L3 (3806) of the conditional branch instruction BrGe (3778)
includes an unconditional branch instruction (3808) to L5.
Accordingly, by determining the branch destination of the
conditional branch instruction (3778) as L5, the unconditional
branch instruction (3808) at L3 can be deleted. Additionally, the
jump destination L4 (3812) of the unconditional branch instruction
"Jump" (3802) includes the unconditional branch instruction (3814)
to L5. Accordingly, by determining the branch destination of this
instruction "Jump" as L5, the unconditional branch instruction
(3814) at L4 can be deleted as well. As the result of the
processings for enhancing the ArmCode instruction sequence
execution efficiency for the abstract register machine as described
above, there is obtained the ArmCode program shown in FIGS. 20 and
21.
[0358] Next, description will be turned to a method of generating a
machine instruction train for a real machine from an ArmCode
instruction sequence i.e., ArmCode-R program generated in the
manner described above.
[0359] FIG. 23 is a view showing the types of the physical
registers used in a machine A. More specifically, it is shown at
4260 that 8th to 23rd physical registers can be used for arithmetic
operations "RcArith". Similarly, a "RcAddr" shown at 4262 indicates
a register usable for address calculation, "RcSect" at 4264
indicates a register used for indicating a section start position.
Further, "RcReturn" at 4266 indicates a register used for
restoration from a subprogram, "RcFuncval" at 4268 indicates a
register used for placing therein a function value, "RcParm" at
4270 indicates a register used for placing therein a parameter,
"RcNosave" at 4272 indicates a register which is neither saved nor
restored upon reference to a subprogram, "RcTemp" at 4274 indicates
a register which is used temporally, "RcFixed" at 4276 indicates a
register having the usage fixed, and "RcAny" at 4278 represents all
the registers which are subject to the register allocation.
[0360] FIG. 24 is a view for illustrating a part of correspondence
relations between the physical registers of the machine A and the
abstract registers. It is assumed that the number of the abstract
registers 4280 is arbitrary while the number of the physical
registers 4282 of the machine A is limited to "32". As can be seen
in FIG. 24, there are established correspondences between the
abstract registers (4284) "Funcva10" and "Funcva11" for placing
therein function values and the physical registers "2" and "3", as
indicated by 4290 and 4291. Similarly, correspondences are
established between the abstract registers (8285) "Param0",
"Param1", . . . , "Paramp" for placing parameters therein and the
physical registers "4" to "7", as indicated at 4291 and 4292,
between the abstract registers for arithmetic operations (4286)
"Ar0", "Ar1", . . . , "Arq" and the physical registers "8" to "23",
as indicated by 4292 and 4294, between the abstract registers
(4287) "Addr0", "Addr1", . . . , "Addrr" for the address
calculation and the physical registers "16" to "23", as indicated
by 4293 and 4296, and between the abstract registers (4288)
"Sect0", "Sect1", . . . , "Sects" for indicating the section start
positions and the physical registers "20" to "23", as indicated by
4295 and 4297, respectively. At this juncture, it should be noted
that the number (p+1) of the abstract registers for parameters, the
number (q+1) of the abstract registers for arithmetics operations,
etc. are not restricted to the number of the physical registers but
depend on the numbers of those registers which are required by the
source program. As to the manner in which the abstract registers
are allocated to the physical registers of the target machine,
description will be made later on by reference to FIGS. 26 to
29.
[0361] FIG. 25 is a diagram for illustrating a system for realizing
the machine language generation through a pattern matching
procedure. The illustrated system includes a pattern matching
section 4556 and a table 4630 of machine instruction generating
rules and operates to generate a machine language program 4650 in
response to an ArmCode instruction sequence 4640 of an ArmCode
program as inputted. The table 4630 stores input patterns and
corresponding output patterns in one-to-one correspondence.
Assuming now that one instruction 4602 is fetched from the
instruction sequence 4640 an input pattern which coincides with the
one instruction 4602 is searched for in the table 4630. In the case
of the illustrated example, it is assumed that the instruction 4602
coincides with the input pattern i of the i-th generating rule
4632. Accordingly, a machine instruction 4652 is generated from the
input instruction 4602 in accordance with the generation pattern i
of the i-th generating rule 4632. At this time, processing such as
replacement of the abstract register by the physical register,
modification of the generating rule in consideration of the
environmental conditions or the like is performed, as will be
described hereinafter by reference to FIGS. 29 to 35.
[0362] FIG. 26 is a view showing a part of the machine instruction
generating rules oriented for the machine A. As will be seen in the
figure, the generating rules are parenthesized by braces "{ }"
after a corresponding ArmCode instruction sequence as shown at
4300, 4312 and others. Generation of the corresponding machine
instructions is same as in C language. A symbol ".vertline."
affixed at the head as shown at 4312, 4316 and others represents
alternative between the sequences. The operands Reg1, C, V, and
others for the abstract register machine are expressed by $Reg1,
$C, $V and the like in the braces "{ }".
[0363] In more concrete, manners of generating a machine
instruction for the machine A in correspondence to an abstract
register machine instruction indicated at the first row 4300 for
loading a constant are shown as rows of statements parenthesized by
the braces "{ }", starting from the row 4302. More specifically,
the parenthesized statements describe that if the constant is "0"
(zero) or greater than "0" and smaller than "65536", a machine
instruction is to be generated in accordance with the statement
4304 and if otherwise the machine instructions are to be generated
in accordance with the statements 4308 and 4310. FIG. 28 shows a
machine instruction 4500 which has been generated by applying this
rule to the instruction 4030 shown in FIG. 20. In the case of this
example, the abstract registers are allocated with the physical
registers in correspondence to the types of the abstract registers,
as exemplified by allocation of the physical register $08 to the
abstract register Ar5, the physical register $17 to the abstract
register Ar6 and so forth, as shown in FIG. 27 at 4400.
[0364] Unless the number of the physical registers as requested are
available, the allocation of the physical registers is not
performed in response to the request by the instruction "alloc" but
the physical register allocation processing is again executed at
the time when the physical registers are actually used. By way of
example, the instruction 4046 shown in FIG. 20 indicates a physical
register allocation request for the abstract register Ar17.
However, this instruction contains a designation that the number of
the physical registers to be preserved even after the allocation is
"2". Besides, the priority of this instruction 4046 is relatively
low. Accordingly, it may occur that no physical register allocation
is effected at this time point. In this case, the condition 4048 is
not fulfilled. Accordingly, though no load instruction is generated
in response to the instruction 4050, only the fact that the
abstract register Ar17 represents the value of a variable n is
recorded. Consequently, the comparison instruction 4112 which uses
the abstract register Ar17 is not yet allocated with any physical
register. Thus, the physical register allocation processing is
again executed upon processing this ArmCode instruction. At this
time, the abstract register Ar17 has the highest priority to allow
the allocation to be executed, whereby the load instruction for
setting the value of the register Ar17 is also generated. Assuming
in conjunction with this example that the abstract register Ar17 is
allocated with the physical register $09, the instruction for
loading the value of the variable n is generated in accordance with
the record made at 4046. As a result of this, there are generated
in place of the instruction 4526 in FIG. 28
[0365] "sub $24, $08, $12"
[0366] two instructions:
[0367] "1w $09, n($16)", and
[0368] "sub $24, $08, $09".
[0369] In this way, if the abstract register allocated with no
physical register is to be used, allocation of the physical
register as well as setting a value there in is performed by using
a function "gen" contained in the machine instruction generating
rules shown in FIG. 26 such as the rule 4304 and others.
[0370] The installer for the machine A generates the machine
language program for the machine A from the abstract object program
in the manner described above. At that time, selection of the
optimal machine instruction sequence and the optimal utilization of
the physical registers are attempted in conformance with the target
machine. In the case of the illustrated example, such measures are
adopted that the machine instruction sequence to be generated is
changed in conformance with the magnitude of a constant in
accordance with the generating rule 4302 shown in FIG. 26 and that
correspondences to the abstract registers are established by taking
into account the number and the types of the usable physical
registers, thereby allowing the physical registers such as $11
placed with a value to be used as many times as possible. In case
there make appearance common equations in the generated machine
language program in accompanying the expressions inherent to the
target machine, the optimalization processing such as deletion of
repetitive computation for the common equation may be performed by
resorting to the processing described hereinbefore in conjunction
with FIG. 19.
[0371] FIG. 29 is a flow chart for illustrating a processing flow
of generation of the machine language program. After initialization
(step 4552), one of the ArmCode instructions which constitutes a
part of the abstract object program is fetched (step 4554), and the
pattern matching is performed for checking to which of the patterns
corresponding to the ArmCode instructions described in the machine
instruction generating rules such as shown in FIG. 26 the fetched
ArmCode instruction fits (step 4556). In case no fitting pattern is
found, the matching resultant state is recorded (step 4560), and
then the succeeding ArmCode instruction is fetched. When the
fitting pattern is found, preparation for a machine instruction is
made in accordance with description of the machine language
1generation for the fitting pattern (step 4562). When the register
allocation is requested for the generated machine instructions as
described, the register allocation processing is performed (step
4564). When the memory allocation is requested, the memory
allocation processing is executed (step 4566). For the request for
generation of a real machine instruction, the corresponding
processing is performed (step 4568). When addition of control
information such as the debug control information and others is
requested, the control information as required is added to the
machine language program (step 4570). In case the generation
control information concerning the register allocation, memory
allocation, selection of the instructions to be generated and/or
the like is requested, the corresponding information setting
processing is executed (step 4572). Subsequently, processing
procedure proceeds to a next statement contained in the description
of the machine language generation (step 4576). Execution of the
above-mentioned processing steps 4566 to 4576 is repeated. When the
operation(s) designated in the description of the machine language
generation has been completed (step 4574), a postprocessing for the
generation processing for the pattern of concern is performed (step
4578). At this time, the matching state is altered so as to conform
with the current state (step 4580), and return is made to the
pattern matching processing. When it is detected that the abstract
object program has wholly been processed, the machine language
generation processing comes to an end (step 4582).
[0372] FIG. 30 is a schematic block diagram showing an internal
structure of the installer for generating the machine language
program from the ArmCode program in the manner described above.
Referring to the figure, the installer 4530 generates the machine
language program 4549 from the ArmCode instruction sequence 4531
and the machine instruction generating rules 4532 for the target
machine of concern. The pattern matching is principally effectuated
by making use of a state transition table. To this end, the
generating rules 4532 are once transformed into a state transiting
table 4535 by a state transition table generation program 4533. The
state transition table 4535 contains actions to be executed and the
ID number of the next state to which the transition is to be made
for each of combinations of the individual ArmCode instructions as
inputted and the state ID numbers. In the pattern matching based on
the state transition, a suitable one of action routines 4538 is
selected for execution by reference to the state transition table
in dependence on the ArmCode instruction as inputted and the
current sate. A state stack 4544 serves for recording the state
transition history. On the other hand, a register usage designation
table 4546 contains records concerning the register usage
designations intrinsic to the target machine, while a register
correspondence table 4548 is used for recording correspondence
relations between the abstract registers in the program being
processed and the physical registers.
[0373] FIG. 31 is a view showing types of the physical registers in
a machine B which differs from the machine A in respect to the
instruction scheme. As shown in this figure at 4600, 1st to 7th and
16th to 23rd physical registers of the machine B can be used for
the arithmetic operations as represented by "RcArith". Similarly,
there are represented by "RcAddr" at 4602 the physical register
which can be used for the address calculation, while "RcTemp" at
4614 represents the physical register used temporally. In this
manner, there are indicated in FIG. 31 the usages of the physical
registers in the machine B which differ from those of the machine A
shown in FIG. 23.
[0374] FIG. 32 is a view showing a part of correspondence relations
between the physical registers incorporated in the machine B and
the abstract registers. Although the abstract registers 4620 may be
used in an arbitrary number as in the case of the machine A, the
number of the physical register of the machine B is limited up to
thirty-two. The abstract registers 4624 for placing function values
therein are represented by "Funcval0" and "Funcval1" and
correspondences are established to the physical register "8" and
"9", respectivedly, as indicated by 4631 and 4632. Representing the
abstract registers 4625 used for placing parameters therein by
"Param0", "Param1", . . . , "Pramp", there are established
correspondence relations between these abstract registers and the
physical registers "24" to "29" as indicated by 4633 and 4634. The
abstract registers 4626 used for arithmetic operation and
represented by "RrO", "Ar1", . . . , "Arq" bear correspondence
relations to the physical registers "1" to "7" and "16" to "23", as
indicated by 4635, 4636, 3637 and 4638, respectively. Similarly,
the abstract registers 4627 used for the address calculation and
represented by "Addr0", "Addr1", . . . , "Addrr", respectively,
bear correspondence relations to the physical registers "1" to "7"
and "16" to "23", as indicated by 4639, 4640, 4641 and 4642,
respectively.
[0375] FIG. 33 is a view showing a part of the machine instruction
generating rules oriented for the machine B. By way of example, the
rule 4700 dictates how to generate the machine instruction in
correspondence to the ArmCode instruction for the constant loading.
The rule 4712 is for the machine instruction concerning the loading
from a memory. The rule 4716 indicates how to generate machine
instructions for the ArmCode instruction sequence which dictates
that the result obtained from the addition of registers Reg1 and
Reg2 be placed in the register Reg3. In this way, FIG. 32 shows the
machine instruction generating rules which are required for
translating the abstract object program shown in FIGS. 20 and 21
into a machine language program. FIG. 34 is a view showing the
correspondence relations of the physical registers incorporated in
the machine B to the abstract registers in the program shown in
FIGS. 20 and 21, as exemplified at 4780. More specifically, there
are shown in this figure the results of the register allocation by
the generation control instructions such as "alloc" , "free",
etc.
[0376] FIG. 35 is a view showing examples of the machine
instructions generated by applying the rules shown in FIG. 33 to
the ArmCode instructions shown in FIGS. 20 and 21. More
specifically, referring to FIG. 35, a machine instruction 4800 is
generated by applying the rule 4700 shown in FIG. 33 to the ArmCode
instruction 4030 shown in FIG. 20, and a machine instruction 4802
is generated by applying the rule 4722 to the ArmCode instruction
4032. In this manner, the installer for the machine B applies the
rules shown in FIGS. 20 and 21 to thereby generate the machine
language program for the machine B as shown in FIG. 35.
[0377] As will now be understood from the above description, the
installer for the machine A generates the machine language program
for the machine A with the installer for the machine B generating
the machine language program for the machine B, both from one and
the same abstract object program. These two installers differ from
each other with regard to the applicable machine instruction
generating rules and the physical register usage designations.
However, both installers are same in respect to the contents of the
processing illustrated in FIG. 29.
[0378] As will be appreciated from the foregoing, according to the
instant embodiment of the invention, a major proportion of the
global optimalization processing and the register allocation
optimalization processing are carried out by the compiler which is
independent of the target machines, wherein the information
concerning the flow analysis, register allocation and others
generated by the compiler is transferred to the installer, as a
result of which the installer can generate the machine language
program of improved execution performance or efficiency without
need for complicated processing. Accordingly, even when the
target-oriented machine language program is generated from the
machine-independent abstract object program by the installer(s)
every time the program is activated, there arises substantially no
problem concerning the execution performance and the processing
time taken by the installer.
[0379] Further, according to the instant embodiment, software can
be delivered to a plurality of different target machines in the
form of the same abstract object program without involving
necessity of adjusting the software or re-compilation for each of
the target machines, whereby maintenance and management can
significantly be facilitated.
[0380] Moreover, it is noted that according to the instant
embodiment of the invention, the abstract object program is
decomposed to very fine levels of manipulation when compared with
the source program. Besides, the abstract object program differs
from the source program with regard to the structure as well as
sequence of the descriptions. For these reasons, it is practically
impossible to restore the source program from the abstract object
program. Thus, by delivering a software in the form of the abstract
object program to the users, it is possible for the user to execute
one and the same program by a plurality of computers or machines
and/or change the types of machines as used while maintaining in
secrecy the software implementation schemes and algorithms
contained in the source program.
[0381] It should further be noted that by using the installer
according to the present invention, one and the same source-level
debug system can be made use of by a plurality of machines. An
embodiment directed to this feature of the invention will be
described below by referring to FIGS. 36 to 45.
[0382] FIG. 36 is a block diagram showing a structure of a debug
system to which the installer according to the invention is
applied. Referring to the figure, a debugger 5100 is used for
degugging an abstract object program 5102 generated by compiling a
source program 5101. An installer 5103 implemented according to the
teachings of the invention is used for translating the abstract
object program into a machine language program 5107. A main memory
5104 is employed for storing the machine language program 5107 and
a debug information table 5108. A display unit 5105 serves for
displaying the results to the user while an input device 5106 is
used for receiving the inputs from the user.
[0383] FIG. 37 is a flow chart for illustrating operation of the
debugger. At first, an abstract object program 5102 is read (step
5120). Since the abstract object program contains source
information indicating positions on the source program and others,
a source-abstract object correspondence table is generated on the
basis of the source information (step 5121). Subsequently, the
installer is operated on the abstract object program as inputted,
to thereby generate a machine language program on the main memory
1step 5122). In that case, an abstract object-machine language
correspondence table is generated for establishing correspondence
between the abstract object program and the machine language
program (step 5123). In this conjunction, it is to be noted that in
the case of the instant embodiment, the source-abstract object
correspondence table and the abstract object-machine language
correspondence table are integrated into a single table (referred
to as a source-abstract object-machine language correspondence
table). This table is included in the debug information table 5108.
When the user inputs a command requisite for the debugging (step
5124), the processing flow is branched in dependence on the type of
the inputted command (step 5125). More specifically, when a display
command is inputted, a displaying processing is executed (step
5126). For a break point setting command as inputted, a break point
setting processing is executed (step 5127), while for an execution
command, execution processing is performed (step 5128). Upon
completion of these processings, the flow is repeated, starting
from the step 5125. The command processings mentioned above will be
described in more detail by reference to FIGS. 38 to 43. When the
input command is an exit command, the processing is terminated.
[0384] FIG. 38 is a view showing an example of the display command.
In the case of this example, the display command is for the value
of the variable i. The display command, includes a command name PRT
5131 to be displayed and a variable name i 5132.
[0385] FIG. 39 is a flow chart for illustrating the display
processing in detail. In other words, this figure shows details of
the processing step 5126 shown in FIG. 37. Referring to FIG. 39,
the variable name in the display command is extracted (step 5133).
Subsequently, by consulting the source-abstract object-machine
language correspondence table (hereinafter referred to simply as
correspondence table), the variable name is translated into an
address on the main memory on which the content of that variable is
stored, which is then followed by a step 5135 where the content of
the address determined at the step 5134 is read out from the main
memory (step 5135). Then the content as read out undergoes
translation in accordance with data type of the variable read out
to be thereby displayed on the display device.
[0386] FIG. 40 is a view showing an example of the break-point
setting command. More specifically, this exemplary command is for
setting a break point in the statement numbered "10" in the source
program and composed of a command name (identifier or ID) 5141 and
a statement ID number 5142.
[0387] FIG. 41 is a flow chart for illustrating a break-point
setting processing and shows details of the processing in the step
5127 shown in FIG. 37. Referring to FIG. 41, the statement ID
number in the command is extracted (step 5143). Thereafter, a flag
is set which indicates that the break point has been set at the
corresponding statement ID number in the correspondence table (step
5144).
[0388] FIG. 42 is a view showing an example of execution command,
which commands execution of program and consists only of a command
name 5151.
[0389] FIG. 43 is a flow chart for illustrating execution
processing and shows details of the processing in the step 5128
shown in FIG. 37. Referring to FIG. 43, only one instruction is
first executed (step 5152). This can be realized by running a CPU
in such a mode that trap is validated every time one instruction
has been executed, at this time, the control is transferred back to
the debugger. Subsequently, address of the instruction is extracted
(step 5153), which can be realized, for example, by reading out the
content of a program counter. Finally, in a step 5154, it is
checked by consulting the correspondence table whether the break
point is set at the extracted address. Unless the break point is
set, the processing is repeated, starting from the step 5152, while
the processing comes to an end when the break point is set.
[0390] FIG. 44 is a view showing an example of the source program
which is subject to the debugging. In this figure, the statement
numbers 5160 and descriptions 5161 of the statements in the source
program are shown. It should however be mentioned that the
statement number is not contained in the actual source program. The
following description of the instant embodiment will be made on the
assumption that the source program shown in FIG. 44 is used.
[0391] FIG. 45 is a view showing an example of a source-abstract
object-machine language correspondence table. This correspondence
table is composed of (a) a statement information table and (b) a
variable information table. The statement table includes four
fields which correspond to the source program statement number
5170, the abstract object program instruction address 5171, the
machine language program instruction address 5172 and the
break-point set flag 5173, respectively. Referring to FIG. 45A, an
entry 5174, for example, indicates that the statement numbered "10"
is an instruction located at the address of "000060" in the
abstract object program, while it is an instruction located at the
address of "000040" in the machine language program and that a
break point is set in this statement.
[0392] The variable information table shown in FIG. 45B includes
five fields for a variable name 5175, a variable type 5176, a data
type 5177, a line number 5178 and a machine address 5179,
respectively. The variable names 5185 represent names of variables
in the source program. The variable types 5176 represent
discriminatively local variables and global variables. The data
type 5177 represents the data types 5177 of the variables. The
statement number 5178 represents the position on the source program
at which the variable has been declared. The machine language
address 5179 is the information of the address of the variable on
the machine language program and represents an offset from a frame
pointer in the case of the local variable while representing an
offset from a base address of the variable area in the case of the
global variable. By way of example, an entry 5180 indicates that
the variable i is a local variable, the data type is "int" which is
located in the statement numbered "4" of the source program and
that the offset from the frame pointer on the machine language
program is "-4".
[0393] As will be understood from the above description, the debug
system according to the illustrated embodiment of the invention can
enjoy an advantageous effect that one and the same abstract object
program can be debugged by plural types of systems because the
installer is incorporated for translating the machine-independent
abstract object program into an target machine language
program.
[0394] By utilizing the installer according to the invention, the
abstract object program can be supplied in the form of IC card or
CD-ROM or the like so as to provide a machine-independent
offhand-executable system. For example, by incorporating a game
program in an IC card while incorporating the installers in
individual machines, respectively, it is possible to execute one
and the same game program by different machines (IC card systems).
An exemplary embodiment of such system will be described below by
reference to FIGS. 46 to 50.
[0395] FIG. 46 is a block diagram showing a structure of an IC
system incorporating an installer according to the invention. The
IC card system shown in this figure includes a controller 5000, a
main memory 5002, an IC card read/write device 5005, a keyboard
5006 and a display 5007. The controller 5000 incorporates therein a
CPU 5001. On the other hand, the main memory 5002 incorporates an
installer 5003. An IC card 5008 is coupled to the IC card system
via the IC card read/write device 5005. The program stored in the
IC card is loaded into the main storage as a machine language
program 5004 through the medium of the installer 5003.
[0396] FIG. 47 is a pictorial view showing an outer appearance of
the IC card system. A user can input data with the aid of the
keyboard 5006, while response to the user is displayed on the
display unit 5007. The IC card is inserted through an IC card
insertion slot 5009.
[0397] FIG. 48 is a top plane view of the IC card 5008. Data
transactions between the IC card and the IC card read/write device
are realized via contact points 5010. A storage device 5011 stores
an abstract object program 5012 to be executed and data 5013.
[0398] FIG. 49 is a flow chart for illustrating execution of the
abstract object program incorporated in the IC card. In the first
place, the IC card 5008 is inserted into the IC card slot 5009
(step 5020) to read out the abstract object program and the data
stored in the IC card (step 5021). In response to the inputting of
the abstract object program read out from the IC card, the
controller 5000 activates the installer 5003 (step 5022). As a
result, there is generated in the main memory the target machine
language program 5004, which is then executed (step 5023). As a
result of the execution, the resulting data is written in the IC
card, if it is required, in a step 5024, and the IC card is
returned (step 5025). At this time the transaction comes to an
end.
[0399] FIG. 50 is a block diagram showing a system in which one and
the same abstract object program contained in an IC card is
executed by a plurality of IC card apparatus having different CPUs,
respectively, according to an embodiment of the invention. It is
assumed, by way of example, that the illustrated system includes IC
card apparatuses A and B which incorporate in the respective
controllers a CPU-A 5038 and a CPU-B 5039 which have mutually
different instruction schemes, respectively. When the abstract
object program placed in the IC card 5008 is to be used in the IC
card apparatus A, the abstract object program is translated into a
machine language program A 5036 described in the CPU-A-oriented
machine language. On the other hand, when the abstract object
program of the IC card 5008 is to be used in the IC card abstract
object program the former is translated into a machine language
program B 5037 described in a CPU-B-oriented machine language.
[0400] Although it has been assumed in the above description that
the IC card is used as the medium for storing and carrying the
abstract object program, it should be appreciated that the present
invention can equally be applied to the systems in which CD-ROM,
floppy disk or the like is used.
[0401] FIG. 51 is a block diagram showing a system in which ArmCode
programs are shared by computer systems of different types which
are linked together through a network.
[0402] Connected to a network medium 1101 are a file server 1102
and computer systems which are exemplified by a computer system A
1103 and a computer system B 1104. A disk device 1105 is connected
to the file server 1102 which serves for supplying file data from
the disk device 1105 to the computer systems A and B (1103 and
1104). Each of the computer systems A and B can make access to the
files on the disk device 1105 with the aid of their own remote file
management programs (1106, 1107). Further, the computer systems A
and B incorporate respective instructions (1108, 1109) for
translating the ArmCode program into machine language programs
oriented to these computer systems, respectively.
[0403] When an ArmCode program 1110 on the disk device 1105 is to
be executed by the computer system A, the ArmCode program 1110 made
available through the associated remote file management program
1106 is translated into a machine language program 1111 by the
installer 1108 to be subsequently executed by the computer system
A. Similarly, a machine language program 1112 is generated for
execution by the computer system B as well.
[0404] In this manner, one and the same ArmCode program can be
executed by a plurality of computers of different types connected
to the network, which means that commonability of the object
program is realized.
[0405] In the prior art system, it was impossible to make an object
program commonable to the machines of different types, making it
necessary for each machine to hold an object program having a same
function. In contrast, by consolidating the object program files
required for every types of the machine for a certain function in
an ArmCode program file as described above, there can be assured
advantages mentioned below.
[0406] (1) File capacity of a whole network system can be
reduced.
[0407] (2) The bug correction and extension of function may be
performed only for the ArmCode program without necessitating
simultaneous execution for a plurality of object programs, whereby
time and labor for version management of the object programs can
remarkably be reduced.
[0408] FIG. 52 is a block diagram for explaining replacement of a
computer system in which an ArmCode program is employed by another
type of computer system.
[0409] Referring to the figure, it is assumed that in a computer
system A 1201, a machine language program running thereon is stored
on an associated disk device 1202 in the form of ArmCode program.
In other words, when a certain function is to be implemented by the
computer system A 1201, the ArmCode program 1204 on the disk system
1202 which corresponds to the function is translated into a machine
language program 1205 oriented for the system A 1201 by an
installer 1203 for execution.
[0410] This type of computer system can easily be replaced by
another computer system which incorporates an installer. Namely,
replacement of the computer system A 1201 by another system B 1206
can readily be accomplished only by copying the ArmCode program
1204 on the disk device 1202 onto a disk device 1207. Thus, when a
certain function implemented by the computer system A 1201 is to be
implemented by the computer system B 1206, the ArmCode program
corresponding to that function and copied onto the disk device 1207
is translated into a machine language program 1209 by the installer
1208 to be subsequently executed.
[0411] By adopting the ArmCode as a scheme for reserving programs
on the disk, advantages mentioned below can be obtained.
[0412] (1) For the user, the time and labor involved in exchange or
switching of the computer systems such as recompiling of source
program and regeneration of machine language programs can
considerably be reduced.
[0413] (2) For the manufactures, a system design for maximizing
computer performances can be facilitated because of capability of
generating the machine language without need for taking into
account the exchangeability or switchability of the computer
system.
[0414] As will now be appreciated from the foregoing description,
it is possible according to the teachings of the present invention
to generate a machine language instruction sequence by effectively
making use of the real machine registers by virtue of
optimalization of abstract register usage by the compiler and the
real register allocating function of the installer. Moreover, owing
to the instruction language pattern replace function of the
installer, high-level functional instructions of the real machine
can effectively be utilized.
* * * * *