Panasonic MN103S User Manual page 525

3) Precautions for describing word/halfword data multiply and accumulate instruction and MCRH and
MCRL access instruction
When a word/halfword data multiply and accumulate instruction and MCRH and MCRL access
instruction are executed, the result of the word/halfword data multiply and accumulate instruction is used
to execute the MCRH and MCRL access instruction. For this reason, the next MCRH and MCRL access
instruction must be activated after the result of the word/halfword data multiply and accumulate
instruction, that is required for the MCRH and MCRL access instruction, has been output. Therefore, it is
necessary to provide 3 cycles between the preceding word/halfword data multiply and accumulate
instruction and the succeeding MCRH and MCRL access instruction.
Word/halfword data
multiply and accumulate
instruction
DEC
Instruction
decoding
EX
MEM
WB
This precaution is applicable to the following instructions:
<Word/halfword data multiply and accumulate instructions>
MAC, MACI, MACH, MACIH, MACU, MACIU, MACHU and MACIHU instructions
<MCRH and MCRL access instructions>
PUTCX, CLRMAC, GETCHX and GETCLX instructions
Insert 3 cycles
MCRH and MCRL access instruction
Operation
Figure:16.4.5 Drawing of Pipelining for Precaution (3)
Result available
for reference
Instruction
decoding
Operation
Multiply and accumulate
instruction outputs the result
required for MCRH and MCRL
access instruction
Extension Instruction Specification
Chapter 16
Appendix
XVI - 73