subfc
Subtract From Carrying
PPC440x5 CPU Core User’s Manual Preliminary
Page 430 of 589 instrset.fm.
September 12, 2002
subfc
Subtract From Carrying
(RT) ←¬(RA) + (RB) + 1
if ¬(RA) + (RB) + 1 232 – 1 then
XER[CA] ← 1
else
XER[CA] ← 0
The sum of the ones complement of register RA, register RB, and 1 is stored into register RT.
XER[CA] is set to a value determined by the unsigned magnitude of the result of the subtract operation.
Registers Altered
•RT
• XER[CA]
• CR[CR0] if Rc contains 1
• XER[SO, OV] if OE contains 1
subfc RT, RA, RB OE=0, Rc =0
subfc. RT, RA, RB OE=0, Rc =1
subfco RT, RA, RB OE=1, Rc =0
subfco. RT, RA, RB OE=1, Rc =1
31 RT RA RB OE 8 Rc
0 6 11 16 21 22 31
Table9-30. Extended Mnemonics for subfc, subfc., subfco, subfco.
Mnemonic Operands Function Other Registers
Altered
subc
RT, RA, RB
Subtract (RB) from (RA).
(RT) ←¬(RB) + (RA) + 1.
Place carry-out in XER[CA].
Extended mnemonic for
subfc RT,RB,RA
subc. Extended mnemonic for
subfc. RT,RB,RA CR[CR0]
subco Extended mnemonic for
subfco RT,RB,RA XER[SO, OV]
subco. Extended mnemonic for
subfco. RT,RB,RA CR[CR0]
XER[SO, OV]
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