Chapter 16
Appendix
XVI - 70 Extension Instruction Specification
■ Precautions for extension arithmetic programming
The extension arithmetic units come equipped with the following registers designed specifically to store high-
speed multiply and multiply and accumulate results.
1. Precautions for describing instructions
This section provides precautions for programming associated with describing, arranging and combining
instructions. Failure to observe these precautions may result in malfunction. The following lists such
precautions:
Table:16.4.1 List of Precautions
Preceding instruction Succeeding instruction Arrangement Precaution
Word/halfword data multiply and
accumulate instructions *1
High-speed multiply
instructions *3
Succeeding
Insert 1 or more cycles
between instructions.
Word/halfword data multiply and
accumulate instructions *1
Multiply and
accumulate
instructions *4
Succeeding
Insert 2 or more cycles
between instructions.
Word/halfword data multiply and
accumulate instructions *1
MCRH and MCRL
access instructions *5
Succeeding
Insert 3 or more cycles
between instructions.
Byte data multiply and accumulate
instructions *2
Multiply and
accumulate
instructions *4
Succeeding
Insert 1 or more cycles
between instructions.
Byte data multiply and accumulate
instructions *2
MCRH and MCRL
access instructions *5
Succeeding
Insert 2 or more cycles
between instructions.
*1 The following instructions fall under the category of word/halfword data multiply and accumulate instructions:
MAC, MACI, MACH, MACIH, MACU, MACIU, MACHU and MACIHU instructions
*2 The following instructions fall under the category of byte data multiply and accumulate instructions:
MACB, MACIB, MACBU and MACIBU instructions
*3 The following instructions fall under the category of high-speed multiply instructions:
MULQ, MULQI, MULQU and MULQIU instructions
*4 The following instructions fall under the category of multiply and accumulate instructions:
MAC, MACI, MACH, MACIH, MACU, MACIU, MACHU, MACIHU, MACB, MACIB, MACBU and MACIBU instructions
*5 The following instructions fall under the category of MCRH and MCRL access instructions:
PUTCX, CLRMAC, GETCHX and GETCLX instructions
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