IBM PPC440X5 Manual de usuario descargar pdf (Pagina 351)

100

101

machhwsu

Multiply Accumulate High Halfword to Word Saturate Unsigned

Preliminary PPC440x5 CPU Core User’s Manual

instrset.fm.

September 12, 2002 Page 351 of 589

machhwsu

Multiply Accumulate High Halfword to Word Saturate Unsigned

prod

0:31

← (RA)

0:15

× (RB)

0:15

unsigned

temp

0:32

← prod

0:31

+ (RT)

(RT)

← (temp

1:32

∨

temp

)

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.

If the unsigned sum can be represented in 32 bits, then RT is updated with the low-order 32 bits of the

unsigned sum.

If the unsigned sum cannot be represented in 32 bits, then RT is updated with a value which is “saturated” to

the maximum representable value of 2

–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.

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

1 2 ... 346 347 348 349 350 351 352 353 354 355 356 ... 589 590

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