Subu, Subtract unsigned – NEC Network Controller uPD98502 User Manual
Page 559
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
5
5
5
5
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