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Lsr logical shift right lsr – Motorola DSP96002 User Manual

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MOTOROLA

DSP96002 USER’S MANUAL

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LSR

Logical Shift Right

LSR

Operation:

Assembler Syntax:

LSR D (move syntax - see the Move instruction description.)

LSR S,D (move syntax - see the Move instruction description.)

LSR #shift,D

Description:

Single-bit shift:

Logically shift the low portion of the specified operand one bit to the right. The carry bit receives the LSB

shifted out of the low portion of the source operand. A zero is shifted into bit 31 of the operand. The result

is stored in the low portion of D.

Multi-bit shift:

Logically shift the low portion of the specified operand N bits (up to 63 bits) to the right. The number of bits

to shift is determined by the 11-bit unsigned integer located in the 11 LSBs of the high portion of S or by a

6-bit immediate field in the instruction. The carry bit receives the Nth bit shifted out of the low portion of

the source operand; it is cleared for a shift count of zero. N zeros are shifted into the MSBs of the desti-

nation operand. If more than 32 bits are shifted, zeros will be stored in D and the carry bit. The result is

stored in the low portion of D.

Input Operand(s) Precision: 32-bit integer.

Output Operand Precision: 32-bit integer.

CCR Condition Codes:

C

- Set if the last bit shifted out of the operand is set. Cleared otherwise. Cleared for a

shift count of zero.

V

- Always cleared.

Z

- Set if result is zero. Cleared otherwise.

N

- Set if result is negative. Cleared otherwise.

I

- Not affected.

LR

- Not affected.

R

- Not affected.

A

- Not affected.

ER Status Bits: Not affected.

IER Flags: Not affected.

31

0

0

C

(parallel data bus move)