APPENDIX A MIPS III INSTRUCTION SET DETAILS
494 Preliminary Users Manual S15543EJ1V0UM
DSUBU Doubleword Subtract Unsigned DSUBU
rs
SPECIAL
0 0 0 0 0 0 rt rd 0
0 0 0 0 0
DSUBU
1 0 1 1 1 1
31 26 25 21 20 16 15 11 10 6 5 0
6 5555 6
Format:
DSUBU 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
.
The only difference between this instruction and the DSUB instruction is that DSUBU never traps on overflow. No
integer overflow exception occurs under any circumstances.
This operation is defined in 64-bit mode or in 32-bit kernel mode. Execution of this instruction in 32-bit user or
supervisor mode causes a reserved instruction exception.
Operation:
64 T: GPR [rd] GPR [rs] GPR [rt]
Exceptions:
Reserved instruction exception (32-bit user mode/supervisor mode)