Intel 64 and IA-32 Architectures Software Developers Manual Volume 1, Basic Architecture

7-14 Vol. 1
PROGRAMMING WITH GENERAL-PURPOSE INSTRUCTIONS
7.3.4 Decimal Arithmetic Instructions in 64-Bit Mode
Decimal arithmetic instructions are not supported in 64-bit mode, They are either
invalid or not encodable.
7.3.5 Logical Instructions
The logical instructions AND, OR, XOR (exclusive or), and NOT perform the standard
Boolean operations for which they are named. The AND, OR, and XOR instructions
require two operands; the NOT instruction operates on a single operand.
7.3.6 Shift and Rotate Instructions
The shift and rotate instructions rearrange the bits within an operand. For the
purpose of this discussion, these instructions are further divided subordinate
subgroups of instructions that:
• Shift bits
• Double-shift bits (move them between operands)
• Rotate bits
7.3.6.1 Shift Instructions
The SAL (shift arithmetic left), SHL (shift logical left), SAR (shift arithmetic right),
SHR (shift logical right) instructions perform an arithmetic or logical shift of the bits
in a byte, word, or doubleword.
The SAL and SHL instructions perform the same operation (see Figure 7-6). They
shift the source operand left by from 1 to 31 bit positions. Empty bit positions are
cleared. The CF flag is loaded with the last bit shifted out of the operand.