APPENDIX A MIPS III INSTRUCTION SET DETAILS
Preliminary Users Manual S15543EJ1V0UM 473
DDIV Doubleword Divide DDIV
rs
SPECIAL
0 0 0 0 0 0 rt 0
0 0 0 0 0 0 0 0 0 0

DDIV

0 1 1 1 1 0

31 26 25 21 20 16 15 6 5 0
655 10 6
Format:
DDIV rs, rt
Description:
The contents of general register
rs
are divided by the contents of general register
rt,
treating both operands as 2s
complement values. No overflow exception occurs under any circumstances, and the result of this operation is
undefined when the divisor is zero.
This instruction is typically followed by additional instructions to check for a zero divisor and for overflow.
When the operation completes, the quotient word of the double result is loaded into special register
LO
, and the
remainder word of the double result is loaded into special register
HI
.
If either of the two preceding instructions is MFHI or MFLO, the results of those instructions are undefined. Correct
operation requires separating reads of
HI
or
LO
from writes by two or more instructions.
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-2: LO undefined
HI undefined
T-1: LO undefined
HI undefined
T: L O GPR [rs] div GPR [rt]
HI GPR [rs] mod GPR [rt]
Exceptions:
Reserved instruction exception (32-bit user mode/supervisor mode)