모두의 코드
MOVZX (Intel x86/64 assembly instruction)

작성일 : 2020-09-01 이 글은 1329 번 읽혔습니다.

MOVZX

Move with Zero-Extend

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

0F B6 /r

MOVZX r16 r/m8

RM

Valid

Valid

Move byte to word with zero-extension.

0F B6 /r

MOVZX r32 r/m8

RM

Valid

Valid

Move byte to doubleword, zero-extension.

REX.W + 0F B6 /r

MOVZX r64 r/m8*

RM

Valid

N.E.

Move byte to quadword, zero-extension.

0F B7 /r

MOVZX r32 r/m16

RM

Valid

Valid

Move word to doubleword, zero-extension.

REX.W + 0F B7 /r

MOVZX r64 r/m16

RM

Valid

N.E.

Move word to quadword, zero-extension.

* In 64-bit mode, r/m8 can not be encoded to access the following byte registers if the REX prefix is used: AH, BH, CH, DH.

Instruction Operand Encoding

Op/En

Operand 1

Operand 2

Operand 3

Operand 4

RM

ModRM:reg (w)

ModRM:r/m (r)

NA

NA

Description

Copies the contents of the source operand (register or memory location) to the destination operand (register) and zero extends the value. The size of the converted value depends on the operand-size attribute.

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

Operation

DEST <- ZeroExtend(SRC);

Flags Affected

None.

Protected Mode Exceptions

#GP(0)

  • 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.

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.

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.

Compatibility Mode Exceptions

Same exceptions as in protected mode.

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.

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