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Negative Flag: Difference between revisions
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The '''Negative Flag''' (N) exists on the [[65c816]] as bit 7 of the [[status register]]. | The '''Negative Flag''' (N) exists on the [[65c816]] as bit 7 of the [[status register]]. Although there are no dedicated SEN or CLN instructions to set or clear it, it can be set with [[SEP]] and cleared with [[REP]]. | ||
These instructions affect the negative flag (this bulleted list being 37 long): | These instructions also affect the negative flag (this bulleted list being 37 long): | ||
* [[ADC]] | * [[ADC]] | ||
Revision as of 09:41, 21 July 2024
The Negative Flag (N) exists on the 65c816 as bit 7 of the status register. Although there are no dedicated SEN or CLN instructions to set or clear it, it can be set with SEP and cleared with REP.
These instructions also affect the negative flag (this bulleted list being 37 long):
- ADC
- AND
- ASL
- BIT
- CMP
- CPX
- CPY
- DEC
- DEX
- DEY
- EOR
- INC
- INX
- INY
- LDA
- LDX
- LDY
- ORA
- PLA
- PLB
- PLD
- PLX
- PLY
- ROL
- ROR
- SBC
- TAX
- TAY
- TCD
- TDC
- TSC
- TSX
- TXA
- TXY
- TYA
- TYX
- XBA
Also, LSR always clears the negative flag.
See Also
Reference
- Labiak, Willam. Page 109: https://archive.org/details/Programming_the_65816/page/n119