Command: NEG-Two's Complement Negation
Arguments: DEST: any 8, 16 or 32 bit memory location or register
Usage: NED GEST
Effects: Deplace DEST with its two's complement (The operand is subtracted from zero).
Flags to be set: CF=1 when DEST!=0 else CF=0; OF, SF, ZF, and PF according to the result