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nmacchw
Negative Multiply Accumulate Cross Halfword to Word Modulo Signed
Preliminary PPC440x5 CPU Core User’s Manual
instrset.fm.
September 12, 2002 Page 385 of 589
nmacchw
Negative Multiply Accumulate Cross Halfword to Word Modulo Signed
nprod
0:31
← –((RA)
16:31
× (RB)
0:15
) signed
temp
0:32
← nprod
0:31
+ (RT)
(RT)
← temp
1:32
The low-order halfword of RA is multiplied by the high-order halfword of RB. The signed product is subtracted
from the contents of RT and RT is updated with the low-order 32 bits of the result.
Registers Altered
•RT
• CR[CR0] if Rc contains 1
• XER[SO, OV] if OE contains 1
Architecture Note
This instruction is implementation-specific and programs which use this instruction may not be portable to
other PowerPC Book-E implementations. See Instruction Set Portability on page 250.
nmacchw RT, RA, RB OE=0, Rc=0
nmacchw. RT, RA, RB OE=0, Rc=1
nmacchwo RT, RA, RB OE=1, Rc=0
nmacchwo. RT, RA, RB OE=1, Rc=1
4 RT RA RB OE 174 Rc
0 6 11 16 21 22 31