Labels:book | box | bulletin board | plant | reckoner | shelf | sky OCR: Memory Prefetch queue (empty) 21000 dec ax (emnty) While this inatruction 21001 jmp short empty executes in the 21002 04 (empty Execution Unit 21003 push 21004 puch 21005 lodsb .ultimately 21006 inc stosh a> reads .the as Bus many Intertace Q the Unit branching to here 1007 next instruction bytes 21008 pop as possible into the prefetch queue Prefetch queue Memory push 21000 dec ax push 21001 jmp short lodsb 21002 inc 1003 push 21004 push 21005 lodsh ..the the instruction prefetch byte queue not When comes time 21006 inc and must be fetched from for this instruction 1007 stosh memory with 4-cycle execute 21008 pop read in fact none of the bytes in the queue are relevant now as the queue must be emptied and refilled with the bytes following the branched-to instruction FIGURE 12.5 When the FL ...
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