Intel 64 and IA-32 Architectures Software Developers Manual Volume 2B, Instruction Set Reference, N-Z

4-8 Vol. 2B
INSTRUCTION SET REFERENCE, N-Z
OR—Logical Inclusive OR
Description
Performs a bitwise inclusive OR operation between the destination (first) and source
(second) operands and stores the result in the destination operand location. The
source operand can be an immediate, a register, or a memory location; the destina-
tion operand can be a register or a memory location. (However, two memory oper-
ands cannot be used in one instruction.) Each bit of the result of the OR instruction is
Opcode Instruction
64-Bit
Mode
Compat/
Leg Mode Description
0C ib OR AL, imm8 Valid Valid AL OR imm8.
0D iw OR AX, imm16 Valid Valid AX OR imm16.
0D id OR EAX, imm32 Valid Valid EAX OR imm32.
REX.W + 0D id OR RAX, imm32 Valid N.E. RAX OR imm32 (sign-
extended).
80 /1 ib OR r/m8, imm8 Valid Valid r/m8 OR imm8.
REX + 80 /1 ib OR r/m8*, imm8 Valid N.E. r/m8 OR imm8.
81 /1 iw OR r/m16, imm16 Valid Valid r/m16 OR imm16.
81 /1 id OR r/m32, imm32 Valid Valid r/m32 OR imm32.
REX.W + 81 /1 id OR r/m64, imm32 Valid N.E. r/m64 OR imm32 (sign-
extended).
83 /1 ib OR r/m16, imm8 Valid Valid r/m16 OR imm8 (sign-
extended).
83 /1 ib OR r/m32, imm8 Valid Valid r/m32 OR imm8 (sign-
extended).
REX.W + 83 /1 ib OR r/m64, imm8 Valid N.E.
r/m64 OR imm8 (sign-
extended).
08 /r OR r/m8, r8 Valid Valid r/m8 OR r8.
REX + 08 /r OR r/m8*, r8* Valid N.E. r/m8 OR r8.
09 /r OR r/m16, r16 Valid Valid r/m16 OR r16.
09 /r OR r/m32, r32 Valid Valid r/m32 OR r32.
REX.W + 09 /r OR r/m64, r64 Valid N.E. r/m64 OR r64.
0A /r OR r8, r/m8 Valid Valid r8 OR r/m8.
REX + 0A /r OR r8*, r/m8* Valid N.E. r8 OR r/m8.
0B /r OR r16, r/m16 Valid Valid r16 OR r/m16.
0B /r OR r32, r/m32 Valid Valid r32 OR r/m32.
REX.W + 0B /r OR r64, r/m64 Valid N.E. r64 OR r/m64.
NOTES:
* In 64-bit mode, r/m8 can not be encoded to access the following byte registers if a REX prefix
is used: AH, BH, CH, DH.