NEG - Z80 instruction reference

negNegate 
Negates A, giving its two's complement, which is the same as subtracting A from zero.
2 bytes · 8 cycles
Used in 8-bit and 16-bit arithmetic, logic and bitsZ80 assembly
The screen, keyboard and mouse through portsZ80 assembly
The bigger of two numbersZ80 assembly
A bouncing ballZ80 assembly
 
SZHP/VNC ●●●●1●
● set from the result
1 always 1
Forms  neg  
The contents of A are negated (two's complement). Operation is the same as subtracting A from zero.
         .org 0x8000
        ld a, 5
        neg
        halt