dsp56800e Freescale Semiconductor, Inc, dsp56800e Datasheet - Page 629

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

SXTA.B
Operation:
D[7] → D[23:8]
Description: Take the byte that is located in the low-order 8 bits of the destination AGU address register, and sign
Example:
Explanation of Example:
Condition Codes Affected:
Instruction Fields:
Instruction Opcodes:
Timing:
Memory:
Freescale Semiconductor
SXTA.B Rn
Operation
SXTA.B
Before Execution
R2
extend it to fill all 24 bits, replicating bit 7 through bits 23–8.
SXTA.B R2
Initially, the R2 AGU register holds the value $0000F3. After the SXTA.B R2 instruction is executed,
bit 7 is replicated through the high-order 16 bits. The result is $FFFFF3.
The condition codes are not affected by this instruction.
1 oscillator clock cycle
1 program word
(no parallel move)
Operands
0000F3
Rn
Sign Extend Byte in AGU Register
15
1
C
1
Instruction Set Details
0
; sign extend byte in R2
W
1
0
Assembler Syntax:
SXTA.B
Sign extend the value in an AGU register from bit 7
12
0
11
0
After Execution
R2
1
0
D
1
8
FFFFF3
Comments
7
1
(no parallel move)
0
1
1
4
SXTA.B
R
3
1
R
A-285
R
0