Prefix computer instruction for compatibly extending instruction functionality
AssigneeInternational Business Machines Corporation
InventorsMichael K Gschwind, Valentina Salapura
Life of this patent
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Abstract
A prefix instruction is executed and passes operands to a next instruction without storing the operands in an architected resource such that the execution of the next instruction uses the operands provided by the prefix instruction to perform an operation, the operands may be prefix instruction immediate field or a target register of the prefix instruction execution.
Claims14
A computer system for executing instructions, the system comprising:
- a processor configured to communicate with a main storage, the processor comprising an instruction fetcher, an instruction optimizer and one or more execution units for executing optimized instructions, the processor configured to perform a method comprising:
- obtaining a first instruction and a second instruction for execution, the first instruction preceding the second instruction in program order;
- determining, by the processor, that the first instruction is a prefix instruction, the prefix instruction specifying a first value to be used as a result operand in executing the first instruction and a location for storing the result operand, the second instruction specifying a value to be used as a source operand in executing the second instruction and a location for fetching the source operand, wherein the result operand of the first instruction is the source operand of the second instruction;
- executing the first instruction without storing the result operand at the location specified by the first instruction;
- and
- executing the second instruction using the first value without fetching the source operand from the location specified by the second instruction.
A computer program product for executing instructions, the computer program product comprising a non-transitory storage medium readable by a processing circuit and storing instructions for execution by the processing circuit for performing a method comprising:
- obtaining a first instruction and a second instruction for execution, the first instruction preceding the second instruction in program order;
- determining, by a processor, that the first instruction is a prefix instruction, the prefix instruction specifying a first value to be used as a result operand in executing the first instruction and a location for storing the result operand, the second instruction specifying a value to be used as a source operand in executing the second instruction and a location for fetching the source operand, wherein the result operand of the first instruction is the source operand of the second instruction;
- executing the first instruction without storing the result operand at the location specified by the first instruction;
- and
- executing the second instruction using the first value without fetching the source operand from the location specified by the second instruction.
Dependencies are inferred from the claim text.