Asra, Arithmetic shift right, Example – Freescale Semiconductor StarCore SC140 User Manual
Page 373: Instruction formats and opcodes instruction fields, Operation assembler syntax
ASRA
SC140 DSP Core Reference Manual
A-59
ASRA
Arithmetic Shift Right
ASRA
By One Bit (AGU)
Description
Status and Conditions that Affect Instruction
Status and Conditions Changed by Instruction
None.
Example
asra r2
Instruction Formats and Opcodes
Instruction Fields
Rx
RRRR AGU Source/Destination Register
Operation
Assembler Syntax
Rx>>1
→ Rx
ASRA Rx
ASRA Rx
Performs an arithmetic right shift by one bit on the AGU register (Rx). Moves bits [31:1] into bits [30:0].
Bit 31 remains the same, creating a sign-extension.
Register Address
Bit Name
Description
SR[18]
EXP
Determines which stack pointer is used when the stack pointer is an
operand. Otherwise, the instruction is not affected by SR.
Register/Memory Address
Before
After
R2
$8002 0002
$C001 0001
Instruction
Words Cycles Type
Opcode
15
8
7
0
ASRA Rx
1
1
2
1
1
1
0
R R R R
1
1
1
1
1
1
0
1
0000
N0
0100
—
1000
R0
1100
R4
0001
N1
0101
—
1001
R1
1101
R5
0010
N2
0110
—
1010
R2
1110
R6
0011
N3
0111
SP
1011
R3
1111
R7
Note:
This instruction can specify R8-R15 as operands by using a high register prefix.