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Extension Instruction Specifications
3-33
(b) Note on the description of word/half-word data multiply-and-accumulate instructions and MCRH, MCRL
access instructions
When executing a word/half-word data multiply-and-accumulate instruction followed by an MCRH, MCRL access
instruction, the result produced by the word/half-word data multiply-and-accumulate instruction is used in the
execution of the subsequent MCRH, MCRL access instruction. Therefore, it is essential to not initiate the subsequent
MCRH, MCRL access instruction until after the result that is required from the word/half-word data multiply-and-
accumulate instruction has been output. As a result, two cycles must be inserted between the word/half-word data
multiply-and-accumulate instruction and the subsequent MCRH, MCRL access instruction.
This note applies to the following instructions:
<Word/half-word data multiply-and-accumulate instructions>
MAC instruction, MACH instruction, MACU instruction, MACHU instruction
<MCRH, MCRL access instructions>
PUTCX instruction, CLRMAC instruction, GETCHX instruction, GETCLX instruction
DEC
EX
MEM
WB
Instruction decoding
Operation
Instruction
decoding
Operation
Word/half-word data
MCRH, MCRL access instruction
Insert two cycles
Multiply-and-accumulate
instruction has output the result
that is required by MCRH, MCRL
access instruction
Result can be
referenced
Multiply-and-accumulate instruction