NEC Network Controller uPD98502 - Manual (Page 493)

APPENDIX A MIPS III INSTRUCTION SET DETAILS
Preliminary User’s Manual S15543EJ1V0UM 493
DSUB
Doubleword Subtract
DSUB
rs
SPECIAL
0 0 0 0 0 0
rt rd
0
0 0 0 0 0
DSUB
1 0 1 1 1 0
31 26 25 21 20 16 15 11 10 6 5 0
6 5 5 5 5 6
Format:
DSUB 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.
An integer overflow exception takes place if the carries out of bits 62 and 63 differ (2's complement overflow). The
destination register rd is not modified when an integer overflow exception occurs.
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:
Integer overflow exception
Reserved instruction exception (32-bit user mode/supervisor mode)