# AND — Logical AND

Opcode | Instruction | Op/En | 64-bit Mode | Compat/Leg Mode | Description
--- | --- | --- | --- | --- | ---
24 ib | AND AL, imm8 | I | Valid | Valid | AL AND imm8.
25 iw | AND AX, imm16 | I | Valid | Valid | AX AND imm16.
25 id | AND EAX, imm32 | I | Valid | Valid | EAX AND imm32.
REX.W + 25 id | AND RAX, imm32 | I | Valid | N.E. | RAX AND imm32 sign-extended to 64-bits.
80 /4 ib | AND r/m8, imm8 | MI | Valid | Valid | r/m8 AND imm8.
REX + 80 /4 ib | AND r/m8*, imm8 | MI | Valid | N.E. | r/m8 AND imm8.
81 /4 iw | AND r/m16, imm16 | MI | Valid | Valid | r/m16 AND imm16.
81 /4 id | AND r/m32, imm32 | MI | Valid | Valid | r/m32 AND imm32.
REX.W + 81 /4 id | AND r/m64, imm32 | MI | Valid | N.E. | r/m64 AND imm32 sign extended to 64-bits.
83 /4 ib | AND r/m16, imm8 | MI | Valid | Valid | r/m16 AND imm8 (sign-extended).
83 /4 ib | AND r/m32, imm8 | MI | Valid | Valid | r/m32 AND imm8 (sign-extended).
REX.W + 83 /4 ib | AND r/m64, imm8 | MI | Valid | N.E. | r/m64 AND imm8 (sign-extended).
20 /r | AND r/m8, r8 | MR | Valid | Valid | r/m8 AND r8.
REX + 20 /r | AND r/m8*, r8* | MR | Valid | N.E. | r/m64 AND r8 (sign-extended).
21 /r | AND r/m16, r16 | MR | Valid | Valid | r/m16 AND r16.
21 /r | AND r/m32, r32 | MR | Valid | Valid | r/m32 AND r32.
REX.W + 21 /r | AND r/m64, r64 | MR | Valid | N.E. | r/m64 AND r32.
22 /r | AND r8, r/m8 | RM | Valid | Valid | r8 AND r/m8.
REX + 22 /r | AND r8*, r/m8* | RM | Valid | N.E. | r/m64 AND r8 (sign-extended).
23 /r | AND r16, r/m16 | RM | Valid | Valid | r16 AND r/m16.
23 /r | AND r32, r/m32 | RM | Valid | Valid | r32 AND r/m32.
REX.W + 23 /r | AND r64, r/m64 | RM | Valid | N.E. | r64 AND 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
--- | --- | --- | --- | ---
RM | ModRM:reg (r, w) | ModRM:r/m (r) | N/A | N/A
MR | ModRM:r/m (r, w) | ModRM:reg (r) | N/A | N/A
MI | ModRM:r/m (r, w) | imm8/16/32 | N/A | N/A
I | AL/AX/EAX/RAX | imm8/16/32 | N/A | N/A

## Description ¶

Performs a bitwise AND operation on 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 is set to 1 if both corresponding bits of the first and second operands are 1; otherwise, it is set to 0.

This instruction can be used with a LOCK prefix to allow the it 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 AND 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 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 but the destination is not a memory operand.