maclhws
Multiply Accumulate Low Halfword to Word Saturate Signed
PPC440x5 CPU Core User’s Manual
Preliminary
Page 354 of 589
instrset.fm.
September 12, 2002
maclhws
Multiply Accumulate Low Halfword to Word Saturate Signed
prod
0:31
←
(RA)
16:31
×
(RB)
16:31
signed
temp
0:32
←
prod
0:31
+ (RT)
if ((prod
0
= RT
0
)
∧
(RT
0
≠
temp
1
)) then (RT)
←
(RT
0
||
31
(
¬
RT
0
))
else (RT)
←
temp
1:32
The low-order halfword of RA is multiplied by the low-order halfword of RB. The signed product is summed
with the contents of RT.
If the signed sum can be represented in 32 bits, then RT is updated with the low-order 32 bits of the signed
sum.
If the signed sum cannot be represented in 32 bits, then RT is updated with a value which is “saturated” to the
nearest representable value. That is, if the signed sum is less than –2
31
, then RT is updated with –2
31
. Like-
wise, if the signed sum is greater than 2
31
– 1, then RT is updated with 2
31
– 1.
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.
maclhws
RT, RA, RB
OE=0, Rc=0
maclhws.
RT, RA, RB
OE=0, Rc=1
maclhwso
RT, RA, RB
OE=1, Rc=0
maclhwso.
RT, RA, RB
OE=1, Rc=1
4
RT
RA
RB
OE
492
Rc
0
6
11
16
21 22
31
Summary of Contents for PPC440X5 CPU Core
Page 1: ...PPC440x5 CPU Core User s Manual Preliminary SA14 2613 02 September 12 2002 Title Page...
Page 22: ...User s Manual PPC440x5 CPU Core Preliminary Page 22 of 583 ppc440x5LOT fm September 12 2002...
Page 26: ...User s Manual PPC440x5 CPU Core Preliminary Page 26 of 589 preface fm September 12 2002...
Page 38: ...User s Manual PPC440x5 CPU Core Preliminary Page 38 of 589 overview fm September 12 2002...
Page 94: ...User s Manual PPC440x5 CPU Core Preliminary Page 94 of 589 init fm September 12 2002...
Page 132: ...User s Manual PPC440x5 CPU Core Preliminary Page 132 of 589 cache fm September 12 2002...
Page 158: ...User s Manual PPC440x5 CPU Core Preliminary Page 158 of 589 mmu fm September 12 2002...
Page 218: ...User s Manual PPC440x5 CPU Core Preliminary Page 218 of 589 timers fm September 12 2002...
Page 248: ...User s Manual PPC440x5 CPU Core Preliminary Page 248 of 589 debug fm September 12 2002...
Page 458: ...User s Manual PPC440x5 CPU Core Preliminary Page 458 of 589 regsummIntro fm September 12 2002...
Page 568: ...User s Manual PPC440x5 CPU Core Preliminary Page 568 of 589 instalfa fm September 12 2002...
Page 588: ...User s Manual PPC440x5 CPU Core Preliminary Page 588 of 583 ppc440x5IX fm September 12 2002...
Page 590: ......