Specifications

Intel
®
64 and IA-32 Architectures Software Developer’s Manual Documentation Changes 17
Documentation Changes
Instruction Operand Encoding
...
Opcode Instruction Op/
En
64-bit
Mode
Compat/
Leg Mode
Description
83 /4 ib AND r/m16, imm8 BValid Valid r/m16 AND imm8 (sign-
extended).
83 /4 ib AND r/m32, imm8 BValid Valid r/m32 AND imm8 (sign-
extended).
REX.W + 83 /4
ib
AND r/m64, imm8 BValid N.E. r/m64 AND imm8 (sign-
extended).
20 /r AND r/m8, r8 AValid Valid r/m8 AND r8.
REX + 20 /r AND r/m8
*
, r8
*
AValid N.E. r/m64 AND r8 (sign-
extended).
21 /r AND r/m16, r16 AValid Valid r/m16 AND r16.
21 /r AND r/m32, r32 AValid Valid r/m32 AND r32.
REX.W + 21 /r AND r/m64, r64 AValid N.E. r/m64 AND r32.
22 /r AND r8, r/m8 AValid Valid r8 AND r/m8.
REX + 22 /r AND r8
*
, r/m8
*
AValid N.E. r/m64 AND r8 (sign-
extended).
23 /r AND r16, r/m16 AValid Valid r16 AND r/m16.
23 /r AND r32, r/m32 AValid Valid r32 AND r/m32.
REX.W + 23 /r AND r64, r/m64 AValid N.E. r64 AND 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.
Op/En Operand 1 Operand 2 Operand 3 Operand 4
A ModRM:reg (r, w) ModRM:r/m (r) NA NA
B ModRM:r/m (r, w) imm8 NA NA
C AL/AX/EAX/RAX imm8 NA NA