Program Status Word
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The Program Status Word is an 8-bit register on the SPC700 that stores the values of status flags. They are typically listed in this order: NVPBHIZC. More verbosely:
| Flag Name | Bit Position |
|---|---|
| Negative Flag | bit 7 |
| Overflow Flag | bit 6 |
| Direct Page Flag | bit 5 |
| Break Flag | bit 4 |
| Half-carry flag | bit 3 |
| Interrupt Enable Flag | bit 2 |
| Zero Flag | bit 1 |
| Carry Flag | bit 0 |
Both the PUSH and POP commands can operate on the PSW. The PSW has the value $02 upon entry into the first user code.[2]
See Also
References
- subparagraph 8.1.6, page 3-8-6 of Book I of the official Super Nintendo development manual
- anomie: https://github.com/gilligan/snesdev/blob/master/docs/spc700.txt#L73