dsp56000 Freescale Semiconductor, Inc, dsp56000 Datasheet - Page 447

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

If the opcode-operand portion of the instruction specifies a given source or destination
register, that same register or portion of that register may be used as a source S1 and/or
S2 in the parallel data bus move operation. This allows data to be moved in the same
instruction in which it is being used as a source operand by a data ALU operation. That
is, duplicate sources are allowed within the same instruction. Note that S1 and S2
may specify the same register.
Class I Example:
Explanation of the Class I Example: Prior to execution, the 56-bit A accumulator con-
tains the value $00:800000:000000, the 24-bit X memory location X:$1234 contains the
value $000000, and the 24-bit Y0 register contains the value $000000. The execution of
the parallel move portion of the instruction, A,X:$1234 A,Y0, moves the 24-bit limited
positive saturation constant $7FFFFF into both the X:$1234 memory location and the Y0
register since the signed portion of the A accumulator was in use.
MOTOROLA
X:R
CMPM Y0,A A,X:$1234 A,Y0
X:$1234
A
Y0
:
:
Before Execution
$00:800000:000000
Freescale Semiconductor, Inc.
For More Information On This Product,
X Memory and Register Data Move
INSTRUCTION DESCRIPTIONS
INSTRUCTION SET DETAILS
$000000
$000000
Go to: www.freescale.com
;compare A,Y0 mag., save A, update Y0
X:$1234
A
Y0
$00:800000:000000
After Execution
$7FFFFF
$7FFFFF
X:R
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