6-31
INSTRUCTION SET SUMMARY
6.7.2.Double-Shift Instructions
The SHLD (shift left double) and SHRD (shift right double) instructions shift a specified
number of bits from one operand to another (refer to Figure 6-9). They are provided to facilitate
operations on unaligned bit strings. They can also be used to implement a variety of bit string
move operations.
Figure 6-8. SAR Instruction Operation
0 1 0 0 0 1 0 0 0 1 0 0 0 1 0 0 0 1 0 0 0 1 0 0 0 1 0 0 0 1 1 1
X
Initial State (Positive Operand)
CF
0 0 1 0 0 0 1 0 0 0 1 0 0 0 1 0 0 0 1 0 0 0 1 0 0 0 1 0 0 0 1 1
1
After 1-bit SAR Instruction
1 1 0 0 0 1 0 0 0 1 0 0 0 1 0 0 0 1 0 0 0 1 0 0 0 1 0 0 0 1 1 1
X
Initial State (Negative Operand)
Operand
1 1 1 0 0 0 1 0 0 0 1 0 0 0 1 0 0 0 1 0 0 0 1 0 0 0 1 0 0 0 1 1
1
After 1-bit SAR Instruction
CF
