JPS62175831A - Control system for pipeline with tag - Google Patents

Abstract

PURPOSE:To suppress the deterioration in the executing speed with a pipeline control system by using an instruction containing a tag that indicates the data dependence between instructions and making a pipeline processing control means refer to the tags of an instruction for unfinished processing and an input instruction respectively. CONSTITUTION:A tag part is added to an instruction. A control means 100 sends the instruction directly to a pipeline processing means 200 if no flag is set at the tag part. Then the instruction is executed. If the instruction has data dependence and is not practicable, it is held by a holding register 131. A tag register 111 stores a tag of an unfinished instruction and this tag is erased when the corresponding process is through. A preceding instruction deciding part 120 compares the tag part of the input instruction stored in the register 131 with the contents of the register 111 and supplies the input instruction to the means 200 when this instruction decides that the processing is through with the preceding instruction having the data dependence.

Description

[Detailed Description of the Invention] [Summary] In a pipeline control method, an instruction to which a tag indicating data dependence between instructions is added is used as an instruction, and the tag content and input of each instruction that has not yet been pipelined is processed. Control the order of execution of manual instructions based on the tag contents of the instructions. As a result, the flow of pipeline processing is not disturbed even if a continuation of input instructions with data dependence is input (data processing can be executed at high speed).

[Industrial application field]

The present invention relates to a pipeline control method when data processing is performed by pipeline processing, and particularly to a pipeline control method improved so that data-dependent instructions can be processed at high speed even if they appear successively.

[Conventional technology]

Pipeline processing methods are widely used because they can perform data processing at high speed.

This pipeline processing method connects multiple functional units in series and processes data in parallel.
Processing data at high speed.

This pipeline processing method can perform data processing most efficiently when each functional unit independently executes its instructions.

However, if there is a data dependency between instructions, for example if an input instruction uses the processing result of another preceding instruction, the execution of that manual instruction will depend on the processing of the other preceding instruction. It will be retained until it is completed.

Conventionally, when the execution of a human command depends on the processing result of another preceding command, the execution of that input command and each subsequent command is stopped, and after the preceding command is completed, input is performed based on the processing result. It executed the command and then executed each command that followed it.

[Problem that the invention seeks to solve]

In conventional pipeline processing methods, when a preceding instruction on which an input instruction has data dependence is being processed in the pipeline, execution of the input instruction and subsequent instructions is suspended until the processing of that preceding instruction is completed. Ta.

For this reason, there was a problem in that the flow of the pipeline was disturbed and the overall execution speed decreased. In particular, when instructions with data dependence occur frequently, there is a problem in that the execution speed is significantly reduced and the characteristics of pipeline processing are impaired.

SUMMARY OF THE INVENTION An object of the present invention is to provide a pipeline control method that can suppress data processing speed reduction as much as possible even when data-dependent instructions appear continuously, and can perform high-speed data processing.

[Means for solving problems]

The means taken by the present invention to solve the above-mentioned problems in conventional pipeline processing will be explained with reference to FIG.

FIG. 1(A) is an explanatory diagram of tagged instructions used in the tagged pipeline control method of the present invention, and FIG. 1(B) is a block diagram showing the principle of the tagged pipeline control method of the present invention. It is something.

In the tagged instruction shown in FIG. 1A, the instruction is set in the 02 section, and the operand of the instruction is written in the operand section.

The tag section is added according to the present invention, and is set with data indicating which resource the instruction utilizes. For example, a bit area is provided corresponding to each resource, and a flag is set in the bit area for the active resource.

In FIG. 1(B), 200 is a known pipeline processing means.

Reference numeral 100 denotes an instruction execution order control means that controls the execution order of input instructions based on the tag contents of each instruction whose processing in the pipeline processing means 200 has not yet been completed and the tag contents of the input instructions.

[For production]

When there is an input instruction, the instruction execution order control means 100 controls the execution order of the input instructions based on the tag contents of each instruction whose processing in the pipeline processing means 200 has not been completed and the tag contents of the input instruction.

For example, if no flag is set in the tag part of the input instruction, or if the tag content of the input instruction does not match the tag content of each instruction that has not finished pipeline processing, the input instruction has data dependency. Since it is determined that there is no preceding instruction, the input instruction is added to the pipeline processing means 200 without being reserved.

In addition, even if the tag content of a human-powered instruction matches any of the tag content of each instruction that has not yet been processed in the pipeline, if the execution of that input instruction can be postponed, only the execution of that input instruction is deferred. to execute the next input command.

When there is an input instruction whose execution is withheld, the instruction execution sequential control means 100 also sets the tag content of this reserved input instruction as the tag content of each instruction whose pipeline processing has not yet been completed, and the tag content of the next input instruction. Based on the comparison, the instruction order is controlled as in the example above.

In pipeline processing, even if there is a preceding instruction whose input instruction has data dependence among the instructions that have not yet been processed in the pipeline, the execution of that input instruction is often postponed to a later time. With tagged pipeline control, even if instructions with data preservation properties are input continuously, the flow of the pipeline is significantly less likely to be disrupted, and data can be processed at high speed.

〔Example〕

An embodiment of the invention will be described with reference to FIG.

FIG. 2 is a block diagram showing the configuration of an apparatus for implementing the present invention.

In FIG. 2, the instruction execution order control means 100 and pipeline processing means 200 are as described in FIG. 1.

In the instruction execution order control means 100, a tag holding unit 110 includes a tag register 111, an OR circuit 112, and an exclusive OR circuit 113, and holds the tag contents of each instruction that has not yet been pipelined.

The tag register 111 has a bit area corresponding to the tag part in FIG. 1(A), and stores the tag contents input from the exclusive OR circuit 113.

The tag part of the input instruction and the tag register 111 are input to the OR circuit 112 . The tag part of the instruction that has been processed by the pipeline processing means 200 and the output of the OR circuit 113 are added to the exclusive OR circuit 113 .

With this OR circuit 112 and exclusive OR circuit 113,
The tag register 111 holds all the tag contents of each instruction that has not yet been pipelined.

The tag portion of each instruction has a bit area corresponding to each resource to be utilized, and a flag is set in the bit area for each resource utilized by the instruction. Therefore, depending on the presence or absence of a flag in each bit RM area in the tag register 111, it is possible to know the contents of the resources utilized by each instruction whose pipeline processing has not yet been completed. - Note that the instructions for which pipeline processing has not yet been completed include each instruction currently being processed in the pipeline processing means 200 and each input instruction that is on hold, which will be described next.

Reference numeral 120 denotes a preceding instruction determination unit, which compares the tag part of the input instruction with the contents of the tag register 111, and first determines whether there is a preceding instruction on which the manual instruction has data dependence among the instructions that have not yet been processed in the pipeline. Determine. That is, depending on the presence or absence of a flag in the bit area of the tag register 111 that corresponds to the bit area where the flag is set in the tag part of the human instruction, the input instruction may be a preceding instruction with data dependence among the instructions that have not yet been pipelined. The presence or absence can be determined.

The preceding instruction determination unit 120 generates control signals corresponding to each of these cases and applies them to the input control unit 130.

The input control unit 130 includes a reservation register 131 that temporarily stores instructions to be enclosed later, and the input control unit 130 includes a reservation register 131 that temporarily stores instructions to be enclosed later, and
The execution order of input commands is controlled according to each control signal applied from 20.

If no flag is set in the tag section of the input instruction, or if there is no preceding instruction to which the input instruction has data dependence among the instructions that have not yet been processed in the pipeline, the power control unit 130 reserves the input instruction. The data is immediately supplied to the pipeline processing means 200 without any processing, and the predetermined pipeline processing is executed.

If the input instruction (referred to as input instruction (1)) has a data dependency, the preceding instruction (referred to as 11) exists in each instruction whose pipeline processing has not been completed, the input instruction (1) is It is temporarily stored in the reservation register 131, and the next input instruction (input instruction (2)) is processed.At this time, the reserved input instruction (1) also becomes an instruction whose pipeline processing has not been completed, and its tag part is The contents of are stored in the tag register 111.

For the next manual command (2), the tag holding unit 110, the preceding command determining unit 120, and the input control unit 130 perform the above-mentioned processes.

If there is a preceding instruction (referred to as preceding instruction (2)) on which the next manual instruction (2) has data dependence, the next input instruction (2) is also reserved in the reservation register 131.

When pipeline processing for one instruction is completed, the tag part of that instruction is input to exclusive OR circuit 113.

The other input terminal of the exclusive OR circuit 113 is connected to the OR circuit 1.
12 to add the contents of tag register 111.

As a result, the contents of the tag register 111 are updated with the contents of the tag of the instruction being removed.

Therefore, the preceding instruction (1) on which the first input instruction (1) depends
), the contents of the tag register 111 become the contents of the tag part of the input instruction (1) removed.

The preceding instruction determination unit 120 determines the input instruction (tag part 11 and tag register 11) stored in the reservation register 131.
1, and when the processing of the preceding instruction (2) in which the input instruction (1) has data dependence is completed, the input control unit 13 executes the manual instruction (1) that has been suspended until then.
Instruct to 0.

Upon receiving the instruction from the preceding instruction determination unit 120, the input control unit 130 selects the input instruction (1) from the reservation register 131.
is extracted and supplied to the pipeline processing means 200, and the instruction is executed.

Processing for the reserved input command (2) is performed in the same manner.

Thereafter, the execution order of each input command is sequentially controlled in the same manner.

If a preceding instruction on which an input instruction depends exists among the instructions that have not yet been pipelined, and there is no free space in the reserved register, the execution of that input instruction and the following input instructions will be executed as in the conventional method. It is held on hold until the pipeline processing of the preceding instruction is completed.

As described above, even if input instructions with data dependence are continuously input into each preceding instruction that has not yet finished pipeline processing, the flow of pipeline processing can be performed smoothly without being disturbed. .

Note that the number of manual instructions that the reservation register 131 can temporarily store is not limited to two, but can generally store a plurality of instructions.

〔Effect of the invention〕

As explained above, according to the present invention, even if a manual instruction with data dependence is continuously input into each preceding instruction whose pipeline processing has not been completed, if the input instruction is to be passed later, Since execution of only the input command can be suspended and other input commands can be continued, even if the data-dependent input commands are manually input one after another, the flow of pipeline processing will not be disrupted. Data processing can be performed at high speed.

[Brief explanation of drawings]

FIG. 1: An explanatory diagram of the principle of the present invention and tagged instructions used in the present invention. FIG. 2: An explanatory diagram of an implementation device of the present invention. 1 and 2, 100: instruction execution order control means, 110: tag holding unit, 120: preceding instruction determination unit, 130: input control unit, 200: pipeline Processing means.

Claims (2)

[Claims] (1) In the pipeline control method, (a) instructions with tags that support data dependence between each instruction are used, and (b) tag contents of each instruction that has not yet been pipeline processed and input instructions are used. A tagged pipeline control method characterized by controlling the execution order of input instructions based on tag contents. (2) If an instruction whose input instruction has data dependence exists in each instruction that has not yet been processed in the pipeline, only the execution of that input instruction is reserved. Tagged pipeline control method described in section.