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RTL: Difference between revisions
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'''RTL''' (Return from Subroutine Long) is a [[65c816]] instruction used to return control from a subroutine that may have been called from a different [[bank]]. | '''RTL''' (Return from Subroutine Long) is a [[65c816]] instruction used to return control from a subroutine that may have been called from a different [[bank]]. | ||
RTL pulls the [[return address]] from the stack, but increments the value by one before loading it into the [[program counter]]. The calling bank is then pulled into the [[program bank register]]. In other words, RTL unwinds what JSL did to the stack. | |||
No flags are affected. | No flags are affected. | ||
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RTL works even in [[emulation mode]], but it is intended primarily for native mode. | RTL works even in [[emulation mode]], but it is intended primarily for native mode. | ||
[[File:rtl.png]] | |||
=== See Also === | === See Also === | ||
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=== External Links === | === External Links === | ||
* [[Eyes & Lichty]] | * [[Eyes & Lichty]], [https://archive.org/details/0893037893ProgrammingThe65816/page/494 page 494] on RTL | ||
* [[Labiak]], [https://archive.org/details/Programming_the_65816/page/n187 page 177] on RTL | * [[Labiak]], [https://archive.org/details/Programming_the_65816/page/n187 page 177] on RTL | ||
* snes9x implementation of RTL: https://github.com/snes9xgit/snes9x/blob/master/cpuops.cpp#L2879 | * snes9x implementation of RTL: https://github.com/snes9xgit/snes9x/blob/master/cpuops.cpp#L2879 | ||
Latest revision as of 21:46, 10 August 2024
| Basic Info | |||||||
|---|---|---|---|---|---|---|---|
| Addressing Mode | Opcode | Length | Speed | ||||
| Stack (RTL) | 6B | 1 byte | 6 cycles | ||||
| Flags Affected | ||||||||
|---|---|---|---|---|---|---|---|---|
| N | V | M | X | D | I | Z | C | |
| . | . | . | . | . | . | . | . | |
RTL (Return from Subroutine Long) is a 65c816 instruction used to return control from a subroutine that may have been called from a different bank.
RTL pulls the return address from the stack, but increments the value by one before loading it into the program counter. The calling bank is then pulled into the program bank register. In other words, RTL unwinds what JSL did to the stack.
No flags are affected.
Syntax
RTL
RTL works even in emulation mode, but it is intended primarily for native mode.
See Also
External Links
- Eyes & Lichty, page 494 on RTL
- Labiak, page 177 on RTL
- snes9x implementation of RTL: https://github.com/snes9xgit/snes9x/blob/master/cpuops.cpp#L2879
- Clark, Bruce. http://www.6502.org/tutorials/65c816opcodes.html#6.2.2.2