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A39E: Negate HL
Used by the routine at DrawLine.
Replaces HL with its two's complement (i.e. HL=00 - HL).
Input
HL The value
Output
HL The negated value
NegateHL A39E PUSH DE Stash DE on the stack.
A39F EX DE,HL DE=HL.
A3A0 LD HL,$0000 HL=00.
A3A3 AND A Subtract the value.
A3A4 SBC HL,DE
A3A6 POP DE Restore DE from the stack.
A3A7 RET Return.
View the equivalent code in;
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