dsp56000 Freescale Semiconductor, Inc, dsp56000 Datasheet - Page 494

• Manufacturer Part Number: dsp56000
• Description: 24-bit Digital Signal Processor Family Manual
• Manufacturer: Freescale Semiconductor, Inc

Operation:
Description: Multiply the two signed 24-bit source operands S1 and S2 and store the
resulting product in the specified 56-bit destination accumulator D. Or, multiply the
signed 24-bit source operand S by the positive 24-bit immediate operand 2
subtract to/from the specified 56-bit destination accumulator D. The “–” sign option is
used to negate the specified product prior to accumulation. The default sign option is “+”.
Note: When the processor is in the Double Precision Multiply Mode, the following
instructions do not execute in the normal way and should only be used as part of the
double precision multiply algorithm shown in Section 3.4 DOUBLE PRECISION MULTI-
PLY MODE:
All other Data ALU instructions are executed as NOP’s when the processor is in the Dou-
ble Precision Multiply Mode.
Example 1:
A - 228
MPY
MPY
MPY Y0, X0, A
S1 S2
S1 S2
MAC X1, Y0, A
MAC X0, Y1, A
MAC Y1, X1, A
(S1 2
MPY –X1,Y1,A #$543210,Y0
X1
Y1
A
-n
:
:
) D (no parallel move)
D (parallel move)
D (parallel move)
$00:000000:000000
Before Execution
Freescale Semiconductor, Inc.
For More Information On This Product,
$C00000
$800000
MPY Y0, X0, B
MAC X1, Y0, B
MAC X0, Y1, B
MAC Y1, X1, B
INSTRUCTION DESCRIPTIONS
INSTRUCTION SET DETAILS
Go to: www.freescale.com
Signed Multiply
;–(X1 Y1)
Assembler Syntax:
X1
Y1
A
MPY ( )S1,S2,D (parallel move)
MPY ( )S2,S1,D (parallel move)
MPY
$FF:C00000:000000
After Execution
)S,#n,D (no parallel move)
A, update Y0
$C00000
$800000
MOTOROLA
-n
and add/