JPS62221030A - Microprogram control system - Google Patents

Abstract

PURPOSE:To attain the optimum compression of a microinstruction in response to its processing by rewriting the value of the fixed data with a microinstruction, therefore, setting a micro-operation pattern which changes by the processing type of the microprogram and has a high emerging factor as the fixed data for each processing before executing processing. CONSTITUTION:A microinstruction held by a microinstruction holding register 6 is partly sent to a microaddress selector 10 as a microaddress part 8b. A sequence part 8c is supplied to the selector 10 to decide the part 8b or the address of a +1 address circuit 9 as the next microaddress. While other microinstructions are outputted to the control subjects as control microinstructions 8a. In case a store micro-operation part 3b for store micro- instruction 3 contains a rewriting indication and the write data, a fixed data part 7 rewrites the fixed data into the write data based on a rewriting indication.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to microprogram control systems, and more particularly to compression of microinstructions.

[Conventional technology]

Conventionally, micro-instruction compression has been achieved using an encoding control method in which micro-operation signals are divided into appropriate groups and encoded for each group.

[Problem that the invention seeks to solve]

In the conventional encoding control method described above, the bit width of the stored microinstruction stored in the control memory and the bit width of the microinstruction held in the microinstruction holding register are the same, and more microoperations can be performed in one microinstruction. In order to do this with instructions, further compression of the stored microinstructions is required. However, it has been impossible to make the bit width of the stored microinstruction smaller than the bit width of the microinstruction and expand it to the bit width of the microinstruction during execution using only encoding control means.

Therefore, when using a microprogram control method that makes the bit width of the stored microinstruction stored in the control memory smaller than the bit width of the microinstruction held in the microinstruction holding register, it is necessary to and transfers the stored microinstruction to the corresponding field of the microinstruction holding register according to the information,
For fields that are not present in the stored microinstruction, predetermined fixed data can be transferred to the corresponding fields of the microinstruction holding register.

However, in the above-mentioned microprogram control method, data for fields that are not included in the storage microinstruction must use predetermined fixed data that is used most frequently, but it is difficult to determine which microoperation appears the most. Since this differs depending on the type of processing, etc., there is a drawback that depending on the processing, data that is frequently used may not become fixed data, and the stored microinstructions may not be compressed effectively.

SUMMARY OF THE INVENTION It is an object of the present invention to overcome the above points and to reduce the bit width of a store microinstruction stored in a control memory to be smaller than the bit width of a microinstruction held in a microinstruction holding register. An object of the present invention is to provide a microprogram control system that allows fixed data to be transferred to a field of a microinstruction holding register corresponding to a field that is not available to be rewritten.

[Means for solving problems]

A microprogram control system of the present invention is a microprogram control system in which a microinstruction is configured as a collection of microoperation fields, and includes a control memory for storing a storage microinstruction having a bit width smaller than that of the microinstruction; a bit-wide micro-instruction holding register; a presence indicating field provided in the store micro-instruction indicating whether a micro-operation field corresponding to a micro-operation field of the micro-instruction is present in the store micro-instruction; Transferring a micro-operation field that is indicated to be present in the stored micro-instruction according to the contents of an instruction field to a corresponding micro-operation field of the micro-instruction holding register and indicating that it is not present in the stored micro-instruction; transfer control means for transferring fixed data to a corresponding micro-operation field of the micro-instruction holding register in place of the micro-operation field being stored;
fixed data storage means for storing the fixed data in a rewritable manner according to the microinstruction.

〔Example〕

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

The figure is a block diagram showing one embodiment of the present invention. The microprogram control system of this embodiment includes a control memory 1, a microaddress register 2, a transfer control 4, a transfer circuit 5, a microinstruction holding register 6, a fixed data section 7, a +1 address circuit 9, Its main part is composed of the micro address selector 10. In addition,
Reference numeral 3 indicates a storage microinstruction, 3a an existence indication field, 3b a storage microoperation section, 8a a control microinstruction, 8b a microaddress section, and 8C a sequence section.

The transfer circuit 5 selectively outputs the storage micro-operation field input from the storage micro-operation section 3b and the fixed data input from the fixed data section 7 to the micro-instruction holding register 6 under the control of the transfer control 4. It consists of a combination of multiple gates.

The fixed data section 7 is a rewritable memory in which the fixed data is rewritten into write data in response to a rewrite instruction when the storage micro-operation section 3b contains a rewrite instruction and write data.

Next, the operation of the microprogram control system of this embodiment configured as described above will be explained.

First, the storage microinstruction 3 indicated by the microaddress register 2 is output from the control memory 1, and a part of the existence indication field 3a is input to the transfer control 4.

The micro operation field of the storage micro operation unit 3b whose presence is indicated in the presence indication field 3a is the transfer control 4.
is held in the corresponding field of the microinstruction holding register 6 via the transfer circuit 5 under the control of the microinstruction holding register 6. On the other hand, for micro-operation fields whose presence is not indicated in the presence indication field 3a and which do not exist in the storage micro-operation section 3b,
Instead, the corresponding fixed data of the fixed data section 7 is supplied to the corresponding field of the microinstruction holding register 6.

A part of the microinstruction held in the microinstruction holding register 6 is sent to the microaddress selector 10 as a microaddress section 8b, and the sequence section 8C selects the microaddress section 8b as the next microaddress or +1 address circuit 9. is input to the micro address selector 10 which determines which address to select. The remaining microinstructions are output to the controlled object as control microinstructions 8a.

If the storage micro-operation section 3b of the storage micro-instruction 3 includes a rewrite instruction and write data, the fixed data section 7 rewrites the fixed data into write data based on the rewrite instruction.

Therefore, the fixed data section 7 can be rewritten to the optimum fixed data for each process, and in this way, highly efficient microinstruction compression can be performed for each process.

(Effects of the Invention) As explained above, the present invention makes it possible to rewrite the value of fixed data, so that the pattern of frequently occurring micro operations that changes depending on the type of micro program processing etc. can be adjusted for each process before execution of the process. Since it can be set as fixed data, microinstructions can be optimally compressed depending on the processing, and the control memory can be used effectively.

[Brief explanation of drawings]

The figure is a block diagram showing one embodiment of the present invention. In the figure, 1... Control memory, 2... Micro address register, 3...
Storage micro-instruction, 3a...Presence indication field, 3b...Storing micro-operation unit, 4...Transfer control, 5...Transfer circuit, 6...Micro-instruction holding Register, 7...
Fixed data section, 8a...Control microinstruction, 8b...Micro address section, 8C...Sequence section, 9...+1 address circuit, 10...Micro address selector be.

Claims (1)

[Scope of Claim] A microprogram control system in which a microinstruction is configured as a collection of microoperation fields, comprising: a control memory for storing a storage microinstruction having a bit width smaller than that of the microinstruction; a micro-instruction holding register; a presence indication field provided in the stored micro-instruction and indicating whether a micro-operation field corresponding to a micro-operation field of the micro-instruction exists in the stored micro-instruction; Transferring a micro-operation field indicated to be present in the store micro-instruction according to the contents to a corresponding micro-operation field of the micro-instruction holding register and indicating that it is not present in the store micro-instruction; Transfer control means for transferring fixed data instead of the micro-operation field to a corresponding micro-operation field of the micro-instruction holding register; Fixed data storage means for storing the fixed data so that it can be rewritten by the micro-instruction. A microprogram control method characterized by: