NEG—Two's Complement NegationInstruction Operand EncodingDescriptionReplaces the value of operand (the destination operand) with its two's complement. (This operation is equivalent to subtracting the operand from 0.) The destination operand is located in a general-purpose 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.OperationIF DEST = 0 THEN CF := 0;ELSE CF := 1; FI;DEST := [– (DEST)]Flags AffectedThe CF flag set to 0 if the source operand is 0; otherwise it is set to 1. The OF, SF, ZF, AF, and PF flags are set according to the result. Protected Mode Exceptions#GP(0)If the destination is located in 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.OpcodeInstructionOp/ En64-Bit ModeCompat/Leg ModeDescriptionF6 /3NEG r/m8MValidValidTwo's complement negate r/m8.REX + F6 /3NEG r/m8*MValidN.E.Two's complement negate r/m8.F7 /3NEG r/m16MValidValidTwo's complement negate r/m16.F7 /3NEG r/m32MValidValidTwo's complement negate r/m32.REX.W + F7 /3NEG r/m64MValid N.E.Two's complement negate 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/EnOperand 1Operand 2Operand 3Operand 4MModRM:r/m (r, w)NANANA
This UNOFFICIAL reference was generated from the official Intel® 64 and IA-32 Architectures Software Developer’s Manual by a dumb script. There is no guarantee that some parts aren't mangled or broken and is distributed WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.