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BRK (SPC700): Difference between revisions
From SnesLab
(→See Also: SLEEP, STOP) |
(seems to ignore interrupt enable flag) |
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|'''Speed''' | |'''Speed''' | ||
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!colspan="8"|Flags Affected | !colspan="8"|Flags Affected | ||
|+ | |+ | ||
|N | |[[Negative Flag|N]] | ||
|V | |[[Overflow Flag|V]] | ||
|P | |[[Direct Page Flag|P]] | ||
|B | |[[Break Flag|B]] | ||
|H | |[[Half-Carry Flag|H]] | ||
|I | |[[Interrupt Enable Flag|I]] | ||
|Z | |[[Zero Flag|Z]] | ||
|C | |[[Carry Flag|C]] | ||
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'''BRK''' is an [[SPC700]] instruction that triggers a software interrupt. | '''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 ==== | |||
<pre> | |||
BRK | |||
</pre> | |||
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 === | === See Also === | ||
* [[BRK]] | * [[BRK]] (65c816) | ||
* [[SLEEP]] | * [[SLEEP]] | ||
* [[STOP]] | * [[STOP]] | ||
=== References === | === References === | ||
* [https://archive.org/details/SNESDevManual/book1/page/n234 Appendix C-9 of Book I] of the official Super Nintendo development manual | * Table C-16 in [https://archive.org/details/SNESDevManual/book1/page/n234 Appendix C-9 of Book I] of the official Super Nintendo development manual | ||
* [https://github.com/gilligan/snesdev/blob/master/docs/spc700.txt#L368 anomie's SPC700 doc] | |||
[[Category:ASM]] | [[Category:ASM]] | ||
[[Category:Audio]] | [[Category:Audio]] | ||
[[Category:Subroutine Call Return Commands]] | |||
[[Category:One-byte Instructions]] | |||
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