Motorola DSP96002 - Manual (Page 409)

MOTOROLA DSP96002 USER’S MANUAL A - 221
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)