APPENDIX A MIPS III INSTRUCTION SET DETAILS
Preliminary Users Manual S15543EJ1V0UM 533
MULT Multiply MULT
rs
SPECIAL
0 0 0 0 0 0

MULT

0 1 1 0 0 0

0
0 0 0 0 0 0 0 0 0 0
31 26 25 21 20 6 5 0
65 610

rt

5
16 15
Format:
MULT rs, rt
Description:
The contents of general registers
rs
and
rt
are multiplied, treating both operands as signed 32-bit integer. No
integer overflow exception occurs under any circumstances.
In 64-bit mode, the operands must be valid 32-bit, sign-extended values.
When the operation completes, the low-order word of the double result is loaded into special register
LO
, and the
high-order 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 these instructions are undefined. Correct
operation requires separating reads of
HI
or
LO
from writes by a minimum of two other instructions.
Operation:
32 T-2: LO undefined
HI undefined
T-1: LO undefined
HI undefined
T: t GPR [rs] * GPR [rt]
LO t31...0
HI t63...32
64 T-2: LO undefined
HI undefined
T-1: LO undefined
HI undefined
T: t GPR [rs]31...0 * GPR [rt]31...0
LO (t31)32 || t31...0
HI (t63)32 || t63...32
Exceptions:
None