Difference between revisions of "PM Opc NEG"
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; A = 0x01 | ; A = 0x01 | ||
| − | NEG A | + | '''NEG A''' |
; A = 0xFF (0 - 0x01 = 0xFF) | ; A = 0xFF (0 - 0x01 = 0xFF) | ||
; F = (Zero=0):(Carry=1):(Overflow=0):(Sign=1) | ; F = (Zero=0):(Carry=1):(Overflow=0):(Sign=1) | ||
; B = 0x00 | ; B = 0x00 | ||
| − | NEG B | + | '''NEG B''' |
; B = 0x00 (0 - 0x00 = 0x00) | ; B = 0x00 (0 - 0x00 = 0x00) | ||
; F = (Zero=1):(Carry=0):(Overflow=0):(Sign=0) | ; F = (Zero=1):(Carry=0):(Overflow=0):(Sign=0) | ||
; [HL] = 0x80 | ; [HL] = 0x80 | ||
| − | NEG [HL] | + | '''NEG [HL]''' |
; [HL] = 0x80 (0 - 0x80 = 0x80) | ; [HL] = 0x80 (0 - 0x80 = 0x80) | ||
; F = (Zero=0):(Carry=1):(Overflow=1):(Sign=1) | ; F = (Zero=0):(Carry=1):(Overflow=1):(Sign=1) | ||
[[PM_InstructionList|'''« Back to Instruction set''']] | [[PM_InstructionList|'''« Back to Instruction set''']] | ||
Revision as of 00:24, 21 April 2009
NEG = Negate
| Hex | Mnemonic | Cycles |
|---|---|---|
| CE A4 | NEG A | 12 |
| CE A5 | NEG B | 12 |
| CE A6 | NEG [N+#nn] | 20 |
| CE A7 | NEG [HL] | 16 |
Execute
A = Register A B = Register B [N+#nn] = Memory: (I shl 16) or (N shl 8) or #nn [HL] = Memory: (I shl 16) or HL
; NEG Ds ; ; Ds = Source/Destination Ds = 0 - Ds
Description
8-Bits Destination is negated.
Conditions
Zero: Set when result is 0
Carry: Set when result is not 0
Overflow: Set when result is 0x80
Sign: Set when bit 7 of the result is 1
Examples
; A = 0x01 NEG A ; A = 0xFF (0 - 0x01 = 0xFF) ; F = (Zero=0):(Carry=1):(Overflow=0):(Sign=1)
; B = 0x00 NEG B ; B = 0x00 (0 - 0x00 = 0x00) ; F = (Zero=1):(Carry=0):(Overflow=0):(Sign=0)
; [HL] = 0x80 NEG [HL] ; [HL] = 0x80 (0 - 0x80 = 0x80) ; F = (Zero=0):(Carry=1):(Overflow=1):(Sign=1)
