5 smulwy – ARM VERSION 1.2 User Manual
Page 158
ARM Instruction Reference
4-48
Copyright © 2000, 2001 ARM Limited. All rights reserved.
ARM DUI 0068B
4.4.5
SMULWy
Signed multiply (32-bit by 16-bit, top 32-bit result).
Syntax
SMULW<y>{cond} Rd, Rm, Rs
where:
<y>
is either
B
or
T
.
B
means use the bottom end (bits [15:0]) of
Rs
,
T
means
use the top end (bits [31:16]) of
Rs
.
cond
is an optional condition code (see Conditional execution on page 4-4).
Rd
is the ARM register for the result.
Rm, Rs
are the ARM registers holding the operands.
r15 cannot be used for any of
Rd
,
Rm
, or
Rs
.
Any combination of
Rd
,
Rm
, and
Rs
can use the same registers.
Usage
The
SMULWy
instruction multiplies the signed integer from the selected half of
Rs
by the
signed integer from
Rm
, and places the upper 32-bits of the 48-bit result in
Rd
.
Condition flags
This instruction does not affect any flags.
Architectures
This instruction is available in all E variants of ARM architecture v5 and above.
Examples
SMULWB r2,r4,r7
SMULWTVS r0,r0,r9
Incorrect examples
SMULWT r15,r9,r3 ; use of r15 not allowed
SMULWBS r0,r4,r5 ; use of S suffix not allowed