Electrical computers and digital processing systems: processing – Instruction decoding – Predecoding of instruction component
Patent
1997-12-12
2000-10-17
An, Meng-Ai T.
Electrical computers and digital processing systems: processing
Instruction decoding
Predecoding of instruction component
712210, 712212, G06F 938
Patent
active
061346500
ABSTRACT:
A superscalar microprocessor predecodes instruction data to identify the boundaries of instructions and the type of instruction. When the cache line is scanned for dispatch, the first scanned instruction is predicted to be a microcode instruction and is dispatched to the MROM unit. A microcode scan circuit uses the location of the first scanned instruction and the functional bits of the predecode data to multiplex instruction specific bytes of the first scanned instruction to the MROM unit. If the first scanned instruction is not the first microcode instruction, then in a subsequent clock cycle, the first microcode instruction is dispatched the MROM unit and the mispredicted instruction is canceled.
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Calle Mauricio
Southard Shane
Zuraski, Jr. Gerald D.
Advanced Micro Devices , Inc.
An Meng-Ai T.
Merkel Lawrence J.
Patel Gautam R.
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