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Processor Status Register: Difference between revisions
From SnesLab
(Memory/Accumulator Select) |
(X Flag) |
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* [[Overflow Flag]] - V | * [[Overflow Flag]] - V | ||
* [[Memory/Accumulator Select]] - M | * [[Memory/Accumulator Select]] - M | ||
* | * [[Index Register Select]] - X | ||
* [[Decimal Mode]] - D | * [[Decimal Mode]] - D | ||
* [[Interrupt Disable Flag]] - I | * [[Interrupt Disable Flag]] - I | ||
Revision as of 22:57, 17 July 2024
The Processor Status Register (P) is on the 65c816 and contains several flags:
- Negative Flag - N
- Overflow Flag - V
- Memory/Accumulator Select - M
- Index Register Select - X
- Decimal Mode - D
- Interrupt Disable Flag - I
- Zero Flag - Z
- Carry Flag - C
It can be pulled from the stack via PLP and RTI.
There are nine instructions that directly modify these flags, including:[3]
The only transfer instructions that do not modify these flags are TCS and TXS.
See Also
Reference
- Table 18.2 Eyes & Lichty, page 422: https://archive.org/details/0893037893ProgrammingThe65816/page/422
- Figure 17.3, Lbid, page 377: https://archive.org/details/0893037893ProgrammingThe65816/page/n403
- page 262, https://archive.org/details/0893037893ProgrammingThe65816/page/n288