dsp56000 Freescale Semiconductor, Inc, dsp56000 Datasheet - Page 496

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

Instruction Fields 1:
Note: Only the indicated S1 S2 combinations are valid. X1 X1 and Y1 Y1 are not valid.
Timing: 2+mv oscillator clock cycles
Memory: 1+mv program words
Example 2:
Explanation of Example 2: The content of X1 is multiplied by 2
placed in the A accumulator. The net effect of this operation is to divide the content of
X1 by 2
right shifted 9 places and filled with the sign bit (0 for a positive number and 1 for a neg-
ative number) and then the result is placed in the accumulator.
A - 230
MPY
MPY
MPY
S1 S2
X0 X0
Y0 Y0
X1 X0
Y1 Y0
X0 Y1
Y0 X0
X1 Y0
Y1 X1
9
and place the result in the accumulator. An alternate interpretation is that X1 is
X1
A
X1,
:
:
Q Q Q
0 0 0
0 0 1
0 1 0
0 1 1
1 0 0
1 0 1
1 1 0
1 1 1
#9, A
$00:000000:000000
Before Execution
Freescale Semiconductor, Inc.
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INSTRUCTION DESCRIPTIONS
INSTRUCTION SET DETAILS
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Sign
+
–
Signed Multiply
;
k
0
1
X1
A
D d
A 0
B 1
$00:0032A1:908000
After Execution
$654321
-9
and the result is
MOTOROLA