US 5,313,644 AGranted

System having status update controller for determining which one of parallel operation results of execution units is allowed to set conditions of shared processor status word

AssigneeMitsubishi Denki Kabushiki Kaisha

InventorsMasahito Matsuo, Toru Shimizu

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Abstract

A data processing system which is provided with a plurality of operation units and a function which executes a plurality of instructions in parallel by each of these plurality of operation units, respectively, wherein operation results executed by these plurality of operation units are reflected on flags which are included in a processor status word (PSW), thereby, those plurality of instructions are executed in parallel in the respective different operation units, and at that time, results of operation processing of the respective instructions are reflected on the flags included in the PSW, then, the flags can be updated by simple control, and the operation results executed by those plurality of operation units are reflected on the flags included in the PSW according to the order of execution of the instructions, thereby, those plurality of instructions are executed in parallel by the respective different operation units, and at that time, the results of operation processing of the respective instructions are reflected on the flags included in the PSW according to the order of execution of the instructions, whereby enabling to realize the high speed operation without providing such complicated processing as temporarily saving information for reflecting the results of operation processing on the flags until processing of the preceding instructions is finished.

Claims6

Dependent claims

A data processing system comprising:

a plurality of registers which store data;
a first operation unit coupled to each of said plurality of registers and which processes data in response to instructions and outputs a first operation result;
a second operation unit coupled to each of said plurality of registers and which processes data in response to instructions and outputs a second operation result;
a processor status word including one or more flags;
first decision means coupled to said first operation unit and to the processor status word, wherein the first decision means determines whether the first operation result should be used to set the flags;
second decision means coupled to said second operation unit and to the processor status word, wherein the second decision means determines whether the second operation result should be used to set the flags;
a memory including first and second instructions, wherein the instructions are successively stored;
instruction execution control means for making said first operation unit execute the first instruction and said second operation unit execute the second instruction, wherein the first and second instructions are executed in parallel;
and
flag update means coupled to the first and second decision means for performing the following functions:
(i) using the second operation result to set the flags when the second decision means determines that the second operation result should be used to set the flags;
and
(ii) using the first operation result to set the flags when the following two conditions occur:
(a) the second decision means determines that the second operation result should not be used to set the flags and
(b) the first decision means determines that the first operation result should be used to set the flags.

12 more elements

Dependencies are inferred from the claim text.