AMCC PPC405 - Page 331

AMCC Proprietary 331
Revision 1.02 - September 10, 2007
PPC405 Processor
subfme
Subtract from Minus One Extended
Preliminary User’s Manual
subfme
Subtract from Minus One Extended
(RT) ←¬(RA) – 1 + XER[CA]
if
¬(RA) + 0xFFFF FFFF + XER[CA] 2
32
– 1 then
XER[CA]
← 1
else
XER[CA]
← 0
The sum of the ones complement of register RA, –1, and XER[CA] is placed 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
• CR[CR0]
LT, GT, EQ, SO
if Rc contains 1
• XER[SO, OV] if OE contains 1
• XER[CA]
Invalid Instruction Forms
• Reserved fields
Architecture Note
This instruction is part of the PowerPC User Instruction Set Architecture.
subfme RT, RA OE=0, Rc=0
subfme. RT, RA OE=0, Rc=1
subfmeo RT, RA OE=1, Rc=0
subfmeo. RT, RA OE=1, Rc=1
31 RT RA
OE 232 Rc
0 6 11 16 21 22 31
>
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