모두의 코드
OR (Intel x86/64 assembly instruction)

작성일 : 2020-09-01 이 글은 730 번 읽혔습니다.

OR

Logical Inclusive OR

참고 사항

아래 표를 해석하는 방법은 x86-64 명령어 레퍼런스 읽는 법 글을 참조하시기 바랍니다.

Opcode

Instruction

Op/
En

64-Bit
Mode

Compat/
Leg Mode

Description

0C ib

OR AL imm8

I

Valid

Valid

AL OR imm8.

0D iw

OR AX imm16

I

Valid

Valid

AX OR imm16.

0D id

OR EAX imm32

I

Valid

Valid

EAX OR imm32.

REX.W + 0D id

OR RAX imm32

I

Valid

N.E.

RAX OR imm32 (sign-extended).

80 /1 ib

OR r/m8 imm8

MI

Valid

Valid

r/m8 OR imm8.

REX + 80 /1 ib

OR r/m8* imm8

MI

Valid

N.E.

r/m8 OR imm8.

81 /1 iw

OR r/m16 imm16

MI

Valid

Valid

r/m16 OR imm16.

81 /1 id

OR r/m32 imm32

MI

Valid

Valid

r/m32 OR imm32.

REX.W + 81 /1 id

OR r/m64 imm32

MI

Valid

N.E.

r/m64 OR imm32 (sign-extended).

83 /1 ib

OR r/m16 imm8

MI

Valid

Valid

r/m16 OR imm8 (sign-extended).

83 /1 ib

OR r/m32 imm8

MI

Valid

Valid

r/m32 OR imm8 (sign-extended).

REX.W + 83 /1 ib

OR r/m64 imm8

MI

Valid

N.E.

r/m64 OR imm8 (sign-extended).

08 /r

OR r/m8 r8

MR

Valid

Valid

r/m8 OR r8.

REX + 08 /r

OR r/m8* r8*

MR

Valid

N.E.

r/m8 OR r8.

09 /r

OR r/m16 r16

MR

Valid

Valid

r/m16 OR r16.

09 /r

OR r/m32 r32

MR

Valid

Valid

r/m32 OR r32.

REX.W + 09 /r

OR r/m64 r64

MR

Valid

N.E.

r/m64 OR r64.

0A /r

OR r8 r/m8

RM

Valid

Valid

r8 OR r/m8.

REX + 0A /r

OR r8* r/m8*

RM

Valid

N.E.

r8 OR r/m8.

0B /r

OR r16 r/m16

RM

Valid

Valid

r16 OR r/m16.

0B /r

OR r32 r/m32

RM

Valid

Valid

r32 OR r/m32.

REX.W + 0B /r

OR r64 r/m64

RM

Valid

N.E.

r64 OR r/m64.

* 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.

Instruction Operand Encoding

Op/En

Operand 1

Operand 2

Operand 3

Operand 4

I

AL/AX/EAX/RAX

imm8/16/32

NA

NA

MI

ModRM:r/m (r, w)

imm8/16/32

NA

NA

MR

ModRM:r/m (r, w)

ModRM:reg (r)

NA

NA

RM

ModRM:reg (r, w)

ModRM:r/m (r)

NA

NA

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 destination operand can be a register or a memory location. (However, two memory operands cannot be used in one instruction.) Each bit of the result of the OR instruction is set to 0 if both corresponding bits of the first and second operands are 0; otherwise, each bit is set to 1.

This instruction can be used with a LOCK prefix to allow the instruction to be executed atomically.

In 64-bit mode, the instruction's default operation size is 32 bits. Using a REX prefix in the form of REX.R permits access to additional registers (R8-R15). Using a REX prefix in the form of REX.W promotes operation to 64 bits. See the summary chart at the beginning of this section for encoding data and limits.

Operation

DEST <- DEST OR SRC;

Flags Affected

The OF and CF flags are cleared; the SF, ZF, and PF flags are set according to the result. The state of the AF flag is undefined.

Protected Mode Exceptions

#GP(0)

  • If the destination operand points to a non-writable segment.

  • If a memory operand effective address is outside the CS, DS, ES, FS, or GS segment limit.

  • If the DS, ES, FS, or GS register contains a NULL segment selector.

#SS(0)

  • If a memory operand effective address is outside the SS segment limit.

#PF(fault-code)

  • If a page fault occurs.

#AC(0)

  • If alignment checking is enabled and an unaligned memory reference is made while the current privilege level is 3.

#UD

  • If the LOCK prefix is used but the destination is not a memory operand.

Real-Address Mode Exceptions

#GP

  • If a memory operand effective address is outside the CS, DS, ES, FS, or GS segment limit.

#SS

  • If a memory operand effective address is outside the SS segment limit.

#UD

  • If the LOCK prefix is used but the destination is not a memory operand.

Virtual-8086 Mode Exceptions

#GP(0)

  • If a memory operand effective address is outside the CS, DS, ES, FS, or GS segment limit.

#SS(0)

  • If a memory operand effective address is outside the SS segment limit.

#PF(fault-code)

  • If a page fault occurs.

#AC(0)

  • If alignment checking is enabled and an unaligned memory reference is made.

#UD

  • If the LOCK prefix is used but the destination is not a memory operand.

Compatibility Mode Exceptions

Same as for protected mode exceptions.

64-Bit Mode Exceptions

#SS(0)

  • If a memory address referencing the SS segment is in a non-canonical form.

#GP(0)

  • If the memory address is in a non-canonical form.

#PF(fault-code)

  • If a page fault occurs.

#AC(0)

  • If alignment checking is enabled and an unaligned memory reference is made while the current privilege level is 3.

#UD

  • If the LOCK prefix is used but the destination is not a memory operand.

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