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Intel Pentium CPU Instruction Set Reference

NEG instruction - Two's Complement Negation

Code Mnemonic Description
F6 /3 NEG r/m8 Two's complement negate r/m8
F7 /3 NEG r/m16 Two's complement negate r/m16
F7 /3 NEG r/m32 Two's complement negate r/m32


Replaces 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.

Operands Bytes Clocks
reg 2 1 NP
mem 2 + d(0 - 2) 3 NP


ID unaffected DF unaffected
VIP unaffected IF unaffected
VIF unaffected TF unaffected
AC unaffected SF sets according to the result
VM unaffected ZF sets according to the result
RF unaffected AF sets according to the result
NT unaffected PF sets according to the result
IOPL unaffected CF cleared to 0 if the source operand is 0; otherwise it is set to 1
OF sets according to the result