JPH0480823A - Conversion system for machine language instruction train - Google Patents

Abstract

PURPOSE:To describe the machine language instructions as conventional regardless of the limitation of an RISC system by rearranging the instruction trains while maintaining a program function consisting of the instruction trains turned into the blocks. CONSTITUTION:A machine language instruction train block forming means 1 divides a described machine language instruction train 3 into the block instruction trains 4, 5 and 6 at the inlet and the outlet of the train 3 with no consciousness of an RISC system. Meanwhile a block instruction train rearrangement means 2 rearranges the trains 4 - 6 into the block instruction trains 7, 8 and 9 that comply with the limitation of the RISC system.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a reduced instruction set computer (Reduced Instruction Set Computer).
5 truction set computer, hereinafter referred to as RISC. ) This paper relates to a method for converting machine language instruction strings in computer systems that have some restrictions on the combination of instruction strings in machine language source programs, such as the following.

[Conventional technology]

In recent years, RISC systems have emerged due to the demand for higher performance computers. Such a system is based on the central processing unit (CentoraProcess) of conventional computers.
ing Unit, hereinafter referred to as CPU. ), and by removing control over each machine language instruction sequence, a high-performance system is realized by easing the processing load on the CPU. Therefore, in order to use a RISC system at the machine language level, such as a language processing system, it is necessary to take over some of the functions missing from the CPU.

An example of this is that the instruction following a branch instruction is executed regardless of whether the branch is successful or not. Therefore, a no-operation instruction (No-0Pera) is used to synchronize instructions.
tion instruction, hereinafter referred to as a NOP instruction. ) or move another instruction in place of the NOP instruction.

[Problem to be solved by the invention]

As mentioned above, due to the simplification of the CPU in the RISC system, in order to use machine language, it is not possible to describe the processing flow sequentially as designed, as in conventional computer systems, and it is difficult to move instructions or It is necessary to insert a NOP instruction.

This has therefore placed a heavy burden on systems that generate machine language instructions, such as language processing systems.

[Means to solve the problem]

The machine language instruction string conversion method of the present invention includes a machine language instruction string blocking means that divides the instruction string of a machine language source program into flocks so that there is only one control entry and one exit, and a machine language instruction string blocking means. and block instruction sequence rearranging means for rearranging the instruction sequence while maintaining the program functions that the sequence constitutes.

Further, in the machine language instruction string conversion method of the present invention, when converting a source program written without being aware of RISC into a program that is compatible with RISC, the machine language instruction string of the source program is converted into a control entry and an exit, respectively. The block is divided into one block, and the machine language instruction sequence is rearranged while maintaining the program function constituted by the machine language instruction sequence so as to be adapted to RISC.

〔Example〕

Next, the present invention will be explained with reference to the drawings.

FIG. 1 is an explanatory diagram showing one embodiment of the present invention. In the figure, a machine language instruction string blocking means 1 divides a machine language instruction string 3, which has been written without being aware of the RISC system, into block instruction strings 4, 5, and 6 by dividing the instruction string at the entrance and exit of the instruction string. Further, the block instruction sequence rearranging means 2 rearranges the block instruction sequences 4, 5.6 into an instruction block 7.8.9 that satisfies the constraints of the RISC system.

Now, assume the following instruction set. The LD instruction takes two operands, reads one word from the address stored in the register specified by the second operand, and stores it in the register of the first operand. However, there must be at least one instruction between the LD instruction and the instruction that refers to its result, and the delay when the result is referenced by the instruction immediately following the LD instruction is indefinite. When a one-instruction delay occurs in the result of an instruction in this way, it is said that there is a "one-instruction delay."

The ADD instruction takes three operands and stores the sum of the contents of the register of the second operand and the contents or immediate value of the register of the third operand in the register of the first operand.

The SUB instruction takes three operands and stores the difference between the contents of the register of the second operand and the contents or immediate value of the register of the third operand in the register of the first operand.

The BEQ instruction branches to the label indicated by the third operand when the contents of the registers of the first and second operands are equal.

The B instruction branches to the label indicated by the first operand.

The BEQ and B instructions have a one instruction delay and execute the next instruction immediately before control is transferred. The NOP instruction does nothing in particular by itself, but is used to synchronize delayed instructions.

There are four registers, each with $0. $1゜$2. $3
It is described as follows. In particular, the content of $0 is 0 and cannot be changed. Also, for labels, add ":" after the label name.

Consider the instruction string shown in FIG. 2 with the instruction set described above. This is a program that calculates the sum of integers from 0 to a value in the storage area plus 1, and is an example of a program written without being particularly aware of the RISC system. Naturally, if executed as is, a malfunction will occur, so the instruction sequence must be converted.

First, two labels LABELI: (201) and LABEL2: (205) each indicate a control entry, and a BEQ instruction (207) and a B instruction (209>) each indicate a control exit.

Therefore, this instruction string is divided into three block instruction strings as shown in FIG. Each blocked instruction sequence has only one entrance and one exit, so as long as the state of the resources at the time of entry and the state of the resources at the time of exit are satisfied, it does not matter what the state is in the middle. It has no effect on the overall program. Taking advantage of this fact, we next consider rearranging each block instruction sequence.

Looking at the block instruction sequence in FIG. 3(a), since the ADD instruction following the LD instruction refers to the result of the LD instruction, a NOP instruction is required during this period.

However, the third SUB instruction has no dependency on these two instructions, so instead of inserting a NOP instruction,
Move the B command.

In Figure 3(b), even if the branch of the BEQ instruction is taken, the next instruction will be executed immediately, so it is possible to insert a NOP instruction that does not cause any problem, but the ADD instruction is inserted after the BEQ instruction. There is no problem if you execute it with , so swap these two instructions.

The same applies to the block instruction sequence shown in FIG. 3(C).

As a result, the instruction sequence shown in FIG. 4 is obtained, but this instruction sequence is a program that is very difficult to understand from a maintenance standpoint.

As described above, the program creator can simply write a conventional instruction sequence and convert it into an instruction sequence that operates correctly even on a RISC system and fully exhibits its performance. In other words, the program creator can always write the program in the conventional manner without being aware of the limitations of the RISC system.

〔Effect of the invention〕

As explained above, the machine language instruction string conversion method of the present invention is R
This has the effect that it is possible to write machine language instructions as before without being bound by the limitations of the ISC system, and it is also possible to fully utilize the performance of the RISC system.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram showing one embodiment of the present invention, FIG. 2 is an explanatory diagram showing an example of a machine language instruction sequence, FIG. 3 is an explanatory diagram showing the result of instruction sequence blocking, and FIG. It is an explanatory diagram showing the result of column rearrangement. 1... Machine language instruction string blocking means, 2... Block instruction string rearranging means, 3... Machine language instruction string, 4 to 9
...Block instruction sequence.

Claims (1)

[Scope of Claims] 1. Machine language instruction string blocking means for dividing the instruction string of a machine language source program into blocks so that each control has only one entry and exit; and the blocked instruction string. 1. A machine language instruction sequence conversion method, comprising block instruction sequence rearranging means for rearranging the instruction sequence while maintaining program functions. 2. Convert the original program written without being aware of RISC to R
When converting into a program that is compatible with ISC, the machine language instruction sequence of the source program is divided into blocks such that there is one control entry and one control exit, and the program is constituted by the machine language instruction sequence that has been divided into blocks. RISC by rearranging the machine language instruction sequence while maintaining functionality.
2. The machine language instruction string conversion method according to claim 1, wherein the method is adapted to the following.