dsp56800e Freescale Semiconductor, Inc, dsp56800e Datasheet - Page 628

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

SXT.L
Operation:
S[31] → D[MSB:32] (no parallel move)
S[31:0] → D[31:0]
Description: Sign extend a long word that is located in the source register, and place the extended value into the
Usage:
Example:
Explanation of Example:
Condition Codes Affected:
Note:
Instruction Fields:
Instruction Opcodes:
Timing:
Memory:
A-284
SXT.L
Operation
SXT.L
Before Execution
FF,FFF
A2
B2
0
0
destination (D). If the destination register is an accumulator, the high-order bit of the source is repli-
cated into the extension portion (FF2) of the accumulator. The result is not affected by the state of the
saturation bit (SA).
SXT.L is used to ensure that the accumulator extension register correctly reflects the sign of a
long-word value that is moved into it.
SXT.L
Initially, the A accumulator holds the value $0:26A7:0000, and the B accumulator holds
$0:80F3:1CC2. When the SXT.L instruction is executed, the value in B is sign extended to 36 bits and
placed in accumulator A.
The condition codes are not affected by this instruction.
Saturation will not occur when this instruction is executed, even if the SA bit in the OMR is set.
1 oscillator clock cycle
1 program word
(no parallel move)
26A7
80F3
B1
A1
B,A
Operands
FF,FFF
FF
DSP56800E Core Reference Manual
1CC2
0000
B0
A0
Sign Extend Long
15
0
1
; sign extend long word in Y and place in A
C
1
1
1
SXT.L
Assembler Syntax:
W
12
1
1
1
Sign extend long and transfer without saturating
11
An alternate syntax for the preceding instruction if the
1
After Execution
A2
B2
F
0
1
source and the destination are the same
F
S,D
80F3
80F3
F
8
A1
B1
F
7
(no parallel move)
Comments
0
Freescale Semiconductor
F
1CC2
1CC2
F
4
A0
B0
0
3
SXT.L
0
0
1
0