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BBS (SPC700): Difference between revisions
From SnesLab
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Revision as of 17:02, 24 July 2023
| Basic Info | |||||||
|---|---|---|---|---|---|---|---|
| Addressing Mode | Opcode | Length | Speed | ||||
| Direct Page | 03 | 3 bytes | when condition false: 5 cycles
when condition true: 7 cycles |
||||
| Direct Page | 23 | 3 bytes | when condition false: 5 cycles
when condition true: 7 cycles |
||||
| Direct Page | 43 | 3 bytes | when condition false: 5 cycles
when condition true: 7 cycles |
||||
| Direct Page | 63 | 3 bytes | when condition false: 5 cycles
when condition true: 7 cycles |
||||
| Direct Page | 83 | 3 bytes | when condition false: 5 cycles
when condition true: 7 cycles |
||||
| Direct Page | A3 | 3 bytes | when condition false: 5 cycles
when condition true: 7 cycles |
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| Direct Page | C3 | 3 bytes | when condition false: 5 cycles
when condition true: 7 cycles |
||||
| Direct Page | E3 | 3 bytes | when condition false: 5 cycles
when condition true: 7 cycles | ||||
| Flags Clobbered | |||||||
|---|---|---|---|---|---|---|---|
| N | V | P | B | H | I | Z | C |
| . | . | . | . | . | . | . | . |
BBS (Branch on Bit Set) is an SPC700 instruction that performs a branch when a bit in the direct page is set. The direct page byte that bit lives in is the first operand. The bit within that byte is a function of the high nibble of the opcode. The target relative address to jump to is the second operand.
See Also
References
- Appendix C-8 of Book I of the official Super Nintendo development manual