dsp56800e Freescale Semiconductor, Inc, dsp56800e Datasheet - Page 494

• Manufacturer Part Number: dsp56800e
• Description: 16-bit Digital Signal Controller Core
• Manufacturer: Freescale Semiconductor, Inc

IMPYUU
Operation:
S1 × S2 → D
Description: Multiply the two unsigned 16-bit source operands (S1 and S2), and place the 32-bit product in the des-
Usage:
Example:
Explanation of Example:
Condition Codes Affected:
A-150
Before Execution
A2
B2
0
0
tination (D). If the destination is an accumulator, the 32-bit product is stored in the MSP:LSP with ze-
ros propagated in the extension portion (FF2) of the accumulator. The result is not affected by the state
of the saturation bit (SA).
This instruction is used to perform extended-precision multiplication calculations. It provides a meth-
od for calculating one of the intermediate values that is needed when a 32-bit × 32-bit multiplication
is performed, for example. See Section 5.5.3, “Multi-Precision Integer Multiplication,” on page 5-32
for an example that uses the IMPYUU instruction.
IMPYUU A1,B0,Y
Prior to execution, the A accumulator contains the value $0:FFFE:1234, the B accumulator contains
$0:0000:0002, and the 32-bit Y register contains $1234:5678. Execution of the IMPYUU instruction
multiplies the 16-bit (positive) unsigned value in A1 by the 16-bit unsigned value in B0 and stores the
unsigned result ($0001:FFFC) into Y.
The condition codes are not modified by this instruction.
(S1 unsigned; S2 unsigned)
FFFE
0000
1234
A1
B1
Y1
Unsigned Integer Multiply
DSP56800E Core Reference Manual
1234
0002
5678
A0
B0
Y0
; multiply two unsigned integers, store in Y
IMPYUU
Assembler Syntax:
After Execution
A2
B2
0
0
S1,S2,D
FFFE
0000
0001
A1
B1
Y1
Freescale Semiconductor
(no parallel move)
IMPYUU
FFFC
1234
0002
A0
B0
Y0