Freescale Semiconductor SC140 Bitwise Shift Right By One Bit AGU, Lsra r2, Rx1 → Rx 0 → Rx31

Models: SC140

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LSRA

 

 

 

 

LSRA

Bitwise Shift Right By One Bit (AGU)

LSRA

Operation

 

Assembler Syntax

 

(Rx>>>1) → Rx; 0 → Rx[31]

LSRA Rx

 

Description

LSRA Rx

Shifts the contents of an AGU register (Rx) right one bit. Bits [31:1] are copied to bits [30:0]. Bit 31 is cleared.

Status and Conditions that Affect Instruction

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.

Status and Conditions Changed by Instruction

None.

Example

lsra r2

Register/Memory Address

R2

Before

$AAAA AAAA

After

$5555 5555

Instruction Formats and Opcodes

Instruction

Words

Cycles

Type

LSRA Rx

1

1

2

Opcode

158 70

1 1 1 0 R R R R 1 1 1 1 1 1 1 1

Instruction Fields

Rx

RRRR

 

AGU Source/Destination Register

 

 

 

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.

 

SC140 DSP Core Reference Manual

A-227

Page 541
Image 541
Freescale Semiconductor SC140 specifications Bitwise Shift Right By One Bit AGU, Lsra r2, Rx1 → Rx 0 → Rx31, Lsra Rx