
APPENDIX A MIPS III INSTRUCTION SET DETAILS
Preliminary User’s Manual S15543EJ1V0UM
559
SUBU
Subtract Unsigned
SUBU
rs
SPECIAL
0 0 0 0 0 0
rt rd
0
0 0 0 0 0
SUBU
1 0 0 0 1 1
31 26 25 21 20 16 15 11 10 6 5 0
6 5555 6
Format:
SUBU rd, rs, rt
Description:
The contents of general register
rt
are subtracted from the contents of general register
rs
to form a result.
The result is placed into general register
rd
.
In 64-bit mode, the operands must be valid sign-extended, 32-bit values.
The only difference between this instruction and the SUB instruction is that SUBU never traps on overflow.
Operation:
32 T:
GPR [rd]
←
GPR [rs] - GPR [rt]
64 T:
temp
←
GPR [rs] - GPR [rt]
GPR [rd]
←
(temp
31
)
32
|| temp
31...0
Exceptions:
None
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