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RTI: Difference between revisions
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'''RTI''' (Return from INterrupt) is a 65x instruction used to return control from an [[interrupt handler]]. | '''RTI''' (Return from INterrupt) is a 65x instruction used to return control from an [[interrupt handler]]. | ||
===== Pitfalls ===== | |||
* RTI should only be run when the e flag is in the same state as when the interrupt fired | |||
===== Cycle Penalty ===== | ===== Cycle Penalty ===== | ||
Revision as of 01:33, 26 November 2023
| Basic Info | |||||||
|---|---|---|---|---|---|---|---|
| Addressing Mode | Opcode | Length | Speed | ||||
| Stack (RTI) | 40 | 1 byte | 6 cycles* | ||||
| Flags Affected | ||||||||
|---|---|---|---|---|---|---|---|---|
| N | V | M | X | D | I | Z | C | |
| 65c816 native mode | ||||||||
| 6502 emulation mode | . | . | ||||||
RTI (Return from INterrupt) is a 65x instruction used to return control from an interrupt handler.
Pitfalls
- RTI should only be run when the e flag is in the same state as when the interrupt fired
Cycle Penalty
RTI takes one additional cycle in native mode as the program bank register needs to be pulled from the stack.
See Also
External Links
- Eyes & Lichty page 492, on RTI: https://archive.org/details/0893037893ProgrammingThe65816/page/n518
- Labiak page on RTI: https://archive.org/details/Programming_the_65816/page/n186
- MCS6500 Manual page on RTI: https://archive.org/details/mos_microcomputers_programming_manual/page/n152
- Carr page on RTI: https://archive.org/details/6502UsersManual/page/n283
- Leventhal page on RTI: https://archive.org/details/6502-assembly-language-programming/page/n138
- snes9x implementation of RTI: https://github.com/snes9xgit/snes9x/blob/master/cpuops.cpp#L3272
- undisbeliever on RTI: https://undisbeliever.net/snesdev/65816-opcodes.html#rti-return-from-interrupt