dsp56000 Freescale Semiconductor, Inc, dsp56000 Datasheet - Page 554

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

Operation:
Description: Transfer data from the specified source data ALU register S to the speci-
fied destination data ALU accumulator D. TFR uses the internal data ALU data paths;
thus, data does not pass through the data shifter/limiters. This allows the full 56-bit con-
tents of one of the accumulators to be transferred into the other accumulator without
data shifting and/or limiting. Moreover, since TFR uses the internal data ALU data paths,
parallel moves are possible. The TFR instruction only affects the L condition code bit
which can be set by data limiting associated with the instruction’s parallel move opera-
tions.
Example:
Explanation of Example: Prior to execution, the 56-bit A accumulator contains the
value $01:234567:89ABCD, and the 56-bit B accumulator contains the value
$ff:FFFFFF:FFFFFF. The execution of the TFR A,B instruction moves the 56-bit value in
the A accumulator into the 56-bit B accumulator using the internal data ALU data paths
without any data shifting and/or limiting. The value in the B accumulator would have
been limited if a MOVE A,B instruction had been used. Note, however, that the parallel
move portion of the TFR instruction does use the data shifter/limiters. Thus, the value
stored in the 24-bit X1 register (not shown) would have been limited in this example.
This example illustrates a triple move instruction.
A - 288
TFR
S D (parallel move)
TFR A,B A,X1
A
B
:
:
$FF:FFFFFF:FFFFFF
$01:234567:89ABCD
Before Execution
Freescale Semiconductor, Inc.
For More Information On This Product,
Y:(R4+N4),Y0
INSTRUCTION DESCRIPTIONS
INSTRUCTION SET DETAILS
Transfer Data ALU Register
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;move A to B and X1, update Y0
Assembler Syntax:
A
B
TFR S,D (parallel move)
$01:234567:89ABCD
$01:234567:89ABCD
After Execution
MOTOROLA
TFR