NOT

One's Complement Negation

Opcodes

Hex Mnemonic Encoding Long Mode Legacy Mode Description
REX.W + F7 /2 NOT r/m64 A Valid N.E. Reverse each bit of r/m64.
F7 /2 NOT r/m32 A Valid Valid Reverse each bit of r/m32.
F7 /2 NOT r/m16 A Valid Valid Reverse each bit of r/m16.
REX + F6 /2 NOT r/m8* A Valid N.E. Reverse each bit of r/m8.
F6 /2 NOT r/m8 A Valid Valid Reverse each bit of r/m8.

Instruction Operand Encoding

Op/En Operand 0 Operand 1 Operand 2 Operand 3
A NA NA NA ModRM:r/m (r, w)

Description

Performs a bitwise NOT operation (each 1 is set to 0, and each 0 is set to 1) on the destination operand and stores the result in the destination operand location. The destination operand can be a register or a memory location.

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.

Pseudo Code

DEST = NOT DEST;

Flags Affected

None.

Exceptions

64-Bit Mode Exceptions

Exception Description
#UD If the LOCK prefix is used but the destination is not a memory operand.
#AC(0) If alignment checking is enabled and an unaligned memory reference is made while the current privilege level is 3.
#PF(fault-code) If a page fault occurs.
#GP(0) If the memory address is in a non-canonical form.
#SS(0) If a memory address referencing the SS segment is in a non-canonical form.

Compatibility Mode Exceptions

Same as for protected mode exceptions.

Virtual-8086 Mode Exceptions

Exception Description
#UD If the LOCK prefix is used but the destination is not a memory operand.
#AC(0) If alignment checking is enabled and an unaligned memory reference is made.
#PF(fault-code) If a page fault occurs.
#SS(0) If a memory operand effective address is outside the SS segment limit.
#GP(0) If a memory operand effective address is outside the CS, DS, ES, FS, or GS segment limit.

Real-Address Mode Exceptions

Exception Description
#UD If the LOCK prefix is used but the destination is not a memory operand.
#SS If a memory operand effective address is outside the SS segment limit.
#GP If a memory operand effective address is outside the CS, DS, ES, FS, or GS segment limit.

Protected Mode Exceptions

Exception Description
#UD If the LOCK prefix is used but the destination is not a memory operand.
#AC(0) If alignment checking is enabled and an unaligned memory reference is made while the current privilege level is 3.
#PF(fault-code) If a page fault occurs.
#SS(0) If a memory operand effective address is outside the SS segment limit.
#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.