dsp56800e Freescale Semiconductor, Inc, dsp56800e Datasheet - Page 634

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

TFR
Operation:
S → D
S → D
S → D
Description: Transfer data from the specified source data ALU register (S) to the specified data ALU destination
Usage:
Example:
Explanation of Example:
Condition Codes Affected:
A-290
Before Execution
A2
B2
(no parallel move)
(one parallel move)
(two parallel reads)
0
3
(D). The TFR instruction can be used to move the full 36-bit contents from one accumulator to another.
This transfer occurs with saturation when the saturation bit, SA, is set. An exception to this is when an
accumulator is transferred to the Y register. If the source is a 16-bit register, it is first sign extended
and concatenated to 16 zero bits to form a 36-bit value (the Y register is only sign extended) before the
transfer. The TFR instruction only affects the L and SZ bits in the CCR (which can be set by data move-
ment that is associated with the instruction’s parallel operations).
This instruction is very similar to a MOVE instruction but has two uses. First, it can be used to perform
a 36-bit transfer of one accumulator to another. Second, when used with a parallel move, this instruc-
tion allows a register move and a memory move to occur simultaneously in 1 instruction that executes
in 1 instruction cycle.
TFR
Prior to execution, the 36-bit A accumulator contains the value $3:0123:0123, and the 36-bit B accu-
mulator contains the value $3:CCCC:EEEE. Execution of the TFR instruction moves the 36-bit value
in B into the 36-bit A accumulator. If the saturation bit is set (SA = 1) in the OMR register, the saturated
value $0:7FFF:FFFF would be transferred to A.
SZ — Set by result of parallel write to memory according to the standard definition
L
LF
15
— Set if data limiting has occurred during parallel move
CCCC
0123
P4
14
A1
B1
B,A
13
P3
SR
P2
12
Transfer Data ALU Register
MR
DSP56800E Core Reference Manual
P1
11
X:(R0)+,Y1
EEEE
0123
0300
A0
B0
P0
10
I1
9
TFR
Assembler Syntax:
TFR
TFR
I0
8
; move B to A and update Y1, R0
SZ
7
After Execution
6
L
A2
B2
3
3
5
E
S,D
S,D
S,D
U
4
CCCC
CCCC
CCR
A1
B1
N
3
(no parallel move)
(one parallel move)
(two parallel reads)
SR
2
Z
Freescale Semiconductor
V
1
EEEE
EEEE
0300
C
0
A0
B0
TFR