Zilog Z80380 - Manual (Page 143)

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Z380 ™
U SER ' S M ANUAL Z ILOG
DC-8297-03
NEGW
NEGATE HL REGISTER (WORD)
NEGW [HL]
Operation: HL(15-0)
←
-HL(15-0)
The contents of the HL register are negated, that is replaced by its two’s complement value.
Note that 8000h is, replaced by itself, because in two’s complement representation the
negative number with the greatest magnitude has no positive counterpart; for this case, the
Overflow flag is set to 1.
Flags: S: Set if the result is negative; cleared otherwise
Z: Set if the result is zero; cleared otherwise
H: Set if there is a borrow from bit 4 of the result; cleared otherwise
V: Set if the content of the HL register was 8000h before the operation; cleared otherwise
N: Set
C: Set if the content of the HL register was not 0000h before the operation; cleared if the
content of the HL register was 0000h
Addressing Execute
Mode Syntax Instruction Format Time Note
NEGW [HL] 11101101 01010100 2