JPS6217840A - Microprogram control system based upon attribution flag - Google Patents

Abstract

PURPOSE:To shorten the execution timing of succeeding instruction by setting up a prescribed bit in a microinstruction as an attribution flag indicating the characteristics of the instruction and discriminating the flag during the execution of the instruction. CONSTITUTION:The property flag in a prescribed field of a microprogram stored in an instruction register 5 is recognized by a flag recognizing circuit 8. An instruction control circuit 9 controls the execution timing of the succeeding microinstruction stored in the register 5 on the basis of an output signal of the circuit 8. A microinstruction BSF(1) read out from a control storage 4 is executed and the succeeding instruction ALU(0) is read out. The attribution flag of the instruction ALU(0) is recognized, and in case of '0' operating instruction, the instruction is executed in the 5th locking cycle at the transfer of data A to a work register 21 and data A' are stored in the work register 21 in the 6th clock cycle to complete the operation.

Description

[Detailed Description of the Invention] [Summary] A microprogram control method for a data processing device that recognizes flags indicating attributes provided in microinstructions and executes the next instruction so as not to interfere with the currently executing instruction. Control timing and shorten microprogram execution processing time.

[Industrial application field]

The present invention relates to a microprogram control method for a data processing device, and more particularly to a microprogram control method provided with a flag indicating an attribute.

The field of controlling data processing devices with microprograms has expanded, and this will greatly contribute to improving their processing capabilities.

However, a microprogram is a sequence of elementary instructions for data processing, and the time required to process the elementary instructions will affect the processing time of the entire data processing device. Methods that make it possible to reduce processing time have always been sought.

[Conventional technology]

FIG. 3 is a diagram of a conventional example of a microprogram control system, and FIG. 4 is a time chart thereof.

To facilitate understanding of the invention, Hathofas!・Data transfer processing of the pamphlet storage 1 in a data processing device having a storage (BS)] will be explained as an example.

When the arithmetic circuit 2 performs an operation, the data used for the operation is transferred from the buffer storage 1 to the work register 2 of the arithmetic circuit 2.
Transferred to 1.

However, if the required data is not stored in the buffer storage I, the data will be transferred from the main storage (MS) 3 to the buffer storage 1 for use.

Hereinafter, the execution process of the instruction will be explained in chronological order using a time chart.

A microinstruction is read out from the control storage 4 in which the microinstruction is stored to the instruction register 5, and if that instruction is the above-mentioned bus path 1 to storage transfer instruction, then it controls data access between the storage 1 and the main storage 3. The BS/MS control circuit 6 executes an instruction to transfer required data stored in the buffer storage 1 to the work register 21, that is, a pass path instruction (BSF).

However, if the required data is not stored in the storage 1 to the main storage 1, that is, in the case of a BS miss, then the main storage 3 is accessed, and the data is stored in the buffer storage 1 via the buffer storage data storage (BSDB) 7. At the same time, it is transferred to the work register 21.

data A read from storage 3.

B, C, and D, for example, 1 data 8 Hyde total 32 pies 1 ~.

Eight bytes of data are sequentially transferred to bus bus I storage 1 every clock cycle.

However, assuming that only data A is required for the operation in item 2, data A is transferred to the work register 21 in the next fifth clock cycle.

Then, in the eighth clock cycle when the transfer via the BSDB 7 ends, the arithmetic instruction (ALU instruction) is executed in the arithmetic circuit 6, and as a result, data A' is transferred to the work register 22.
is stored in

[Problem that the invention seeks to solve]

In this conventional method, even though the required data has been transferred to the work register, the next arithmetic instruction cannot be executed.

Since BSDB is in a busy state until data A, B, C, and D are transferred, an error will occur if BSDB is used during that time.

On the other hand, since the attributes of the next instruction are not known, that is, whether or not BSDB will be used in this example, the next instruction cannot be executed until the currently executed instruction is completed.

The present invention was created in view of these points, and is a method that can shorten the execution time of a microprogram with a simple configuration in which a flag indicating the attribute of an instruction is provided and a circuit for recognizing the flag is provided. The purpose is to provide.

[Means for solving problems]

A flag indicating the attribute of the microinstruction is provided in a predetermined field, and the microprogram control device includes a flag recognition circuit 8 that recognizes the attribute of the instruction to be executed next to the microinstruction being executed and controls the execution timing of the instruction. An instruction control circuit 9 is provided to recognize whether or not the microinstruction to be executed next has temporal consistency between the microinstruction being executed and the device functions to be used, and if there is no possibility of such a microinstruction being executed, the Executes the next command without waiting for completion.

[Operation] A predetermined bit of a microinstruction is set as a bit representing the characteristics of the instruction, that is, an attribute flag.

In the above example of execution of arithmetic instructions, a predetermined bit of the microprogram is set as an attribute flag in advance, and the flag is given the meaning of "accompanied by access to buffer storage."

That is, the predetermined attribute flag of an instruction that involves access to the buffer storage 1 is set to "1", and the attribute flag of an instruction that does not is set to rOJ.

Then, when processing that instruction, if the flag recognition circuit 8 recognizes the instruction next to the instruction being executed as "0", it will be executed at the timing when the required data A of that instruction has been transferred. The command control circuit 9 controls.

Further, when the flag recognition circuit 8 recognizes "1", the next instruction is executed by the BSDB 7 whose processing is engaged with the instruction being executed.
It is executed after the use of .

〔Example〕

Embodiments of the present invention will be described in detail below with reference to the drawings.

FIG. 1 is a diagram of an embodiment of the present invention; FIG. 2 shows a time chart diagram of FIG.

Note that the same reference numerals indicate the same objects throughout the figures.

Reference numeral 8 denotes a flag recognition circuit that recognizes attribute flags of predetermined fields of the microprogram stored in the instruction register 5.

An instruction control circuit 9 controls the execution timing of the next microinstruction stored in the instruction register 5 based on the recognition output signal of the flag recognition circuit 8.

This embodiment is similar to the conventional example described above.
The image transfer process will be explained below.

The microinstruction B S F (1) instruction (the number in parentheses represents the attribute flag signal of that instruction) read out from the control storage 4 is first read out to the instruction register 5 and executed, and then the next instruction is executed. Read out.

The attribute flag of the read next instruction, the arithmetic instruction ALU (0), is recognized by the flag recognition circuit 8 and set to "0".
In the case of an arithmetic instruction, data A is stored in the work register 21.
is executed in the fifth clock cycle when the
The execution result data A' is stored in the work register 21 in the sixth cross cycle.

That is, the A LIJ (0) instruction is completed in the sixth clock cycle, and the B SF (1) instruction is completed in the seventh clock cycle after transferring data D.

Comparing this figure 2 with the time chart of figure 4 of the conventional example, the ALU instruction is completed in the 6th clock cycle in the former case, but in the 9th clock cycle in the latter case, resulting in a time reduction of 3 clock cycles. I'll take a look at what I've done.

Furthermore, if the buffer storage store instruction B S'S (1), which is an instruction to access the buffer register from the work register 21 engaged in the BSDB 7, is stored in the instruction register 5 as the next instruction, that B S
The S (1) instruction will be executed in the 8th clock cycle after the transfer of data D is completed.

Although the buffer register transfer process has been described above using one bit as the attribute flag, it is also possible to construct a circuit using multiple bits to further shorten the processing time.

〔Effect of the invention〕

As described above, according to the present invention, it is possible to shorten the time for processing instructions of a microprogram control system, and this invention is extremely useful in practice.

[Brief explanation of drawings]

Fig. 1 is a diagram of an embodiment of the microprogram control method using attribute flags of the present invention, Fig. 2 is a time chart diagram of the embodiment of Fig. 1, Fig. 3 is a diagram of a conventional example, and Fig. 4 FIG. 3 is a time chart diagram of the conventional example shown in FIG. 3; In the figure, 8 is a flag recognition circuit;

Claims (1)

[Scope of Claims] A microprogram control device that provides a flag indicating an attribute in a predetermined field of a microinstruction and executes the microinstruction includes a flag recognition circuit (8) that recognizes the flag, and a flag recognition circuit (8) that recognizes the flag. An instruction control circuit (9) is provided which controls the execution timing of the microinstruction based on the recognition output of step 8), and recognizes the flag of the microinstruction next to the microinstruction being executed, and executes the next microinstruction. A microprogram control method using attribute flags, which is characterized by controlling the execution timing of.