AMCC PPC405 - Page 255

AMCC Proprietary 255
Revision 1.02 - September 10, 2007
PPC405 Processor
machhwsu
Multiply Accumulate High Halfword to Word Saturate Unsigned
Preliminary User’s Manual
machhwsu
Multiply Accumulate High Ha lfword to Word Saturate Unsigned
prod
0:31
← (RA)
0:15
x (RB)
0:15
unsigned
temp
0:32
← prod
0:31
+ (RT)
(RT)
← (temp
1:32
∨
32
temp
0
)
The high-order halfword of RA is multiplied by the high-order halfword of RB. The unsigned product is summed
with the contents of RT and the sum is stored in a 33-bit temporary register.
If a result does not overflow, the low-order 32 bits of the temporary register are stored in RT.
If a result overflows, the returned result is the nearest representable value. Thus, if a result is greater than 2
32
–1,
the value stored in RT is 2
32
–1.
Registers Altered
•RT
• CR[CR0]
LT, GT, EQ, SO
if Rc contains 1
• XER[SO, OV] if OE contains 1
Architecture Note
This instruction is part of the Multiply-Accumulate instruction set extensions and complies with the architectural
requirements for APUs of the PowerPC Embedded Environment. As such, it is not part of the PowerPC Architec-
ture, nor is it part of the PowerPC Embedded Environment. Programs that use this instruction may not be portable
to other implementations.
machhwsu RT, RA, RB OE=0, Rc=0
machhwsu. RT, RA, RB OE=0, Rc=1
machhwsuo RT, RA, RB OE=1, Rc=0
machhwsuo. RT, RA, RB OE=1, Rc=1
4RTRARBOE76Rc
0 6 11 16 21 22 31