Computer Hardware User Manual

subfme
Subtract from Minus One Extended
Preliminary PPC440x5 CPU Core User’s Manual
instrset.fm.
September 12, 2002 Page 433 of 589
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] if Rc contains 1
• XER[SO, OV] if OE contains 1
• XER[CA]
Invalid Instruction Forms
• Reserved fields
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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