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BRK (SPC700): Difference between revisions
From SnesLab
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BRK very well could be the only interrupt source on the S-SMP. It is the only instruction to unconditionally set the [[break flag]]. | BRK very well could be the only interrupt source on the S-SMP. It is the only instruction to unconditionally set the [[break flag]]. | ||
According to [[fullsnes]], [[EI]] and [[DI]] have no effect other than toggling the [[interrupt enable flag]], so the SPC700's BRK seems to be non-maskable like the 65c816's [[BRK]]. | |||
To return from the [[interrupt handler]], use [[RETI]]. | To return from the [[interrupt handler]], use [[RETI]]. | ||
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* [[SLEEP]] | * [[SLEEP]] | ||
* [[STOP]] | * [[STOP]] | ||
=== References === | === References === | ||
Latest revision as of 00:31, 14 August 2024
| Basic Info | |||||||
|---|---|---|---|---|---|---|---|
| Addressing Mode | Opcode | Length | Speed | ||||
| Stack / Interrupt | 0F | 1 byte | 8 cycles | ||||
| Flags Affected | |||||||
|---|---|---|---|---|---|---|---|
| N | V | P | B | H | I | Z | C |
| . | . | . | 1 | . | 0 | . | . |
BRK is an SPC700 instruction that triggers a software interrupt. The program counter and flags are pushed to the stack. The program counter then jumps to the address stored at $FFDE.
Syntax
BRK
BRK very well could be the only interrupt source on the S-SMP. It is the only instruction to unconditionally set the break flag.
According to fullsnes, EI and DI have no effect other than toggling the interrupt enable flag, so the SPC700's BRK seems to be non-maskable like the 65c816's BRK.
To return from the interrupt handler, use RETI.
See Also
References
- Table C-16 in Appendix C-9 of Book I of the official Super Nintendo development manual
- anomie's SPC700 doc