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'''RTL''' (Return from Subroutine Long) is a [[65c816]] instruction used to return control from a subroutine that was called from a different bank.
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!colspan="8"|Basic Info
!colspan="8"|Basic Info
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|'''Speed'''
|'''Speed'''
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|stack
|[[Stack Addressing|Stack]] (RTL)
|6B
|6B
|1 byte
|1 byte
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!colspan="9"|Flags Clobbered
!colspan="9"|Flags Affected
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|N
|[[N Flag|N]]
|V
|[[V Flag|V]]
|M
|[[M Flag|M]]
|X
|[[X Flag|X]]
|D
|[[D Flag|D]]
|I
|[[I Flag|I]]
|Z
|[[Z Flag|Z]]
|C
|[[C Flag|C]]
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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 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 ====
<pre>
RTL
</pre>
RTL works even in [[emulation mode]], but it is intended primarily for native mode.
[[File:rtl.png]]


=== See Also ===
=== See Also ===
* [[RTI]]
* [[RTI]]
* [[RTS]]
* [[RTS]]
* [[RET]]
* [[RETI]]
* [[JSL]]
* [[JSR]]


=== External Links ===
=== External Links ===
* [[Eyes & Lichty]] page on RTL: https://archive.org/details/0893037893ProgrammingThe65816/page/n520
* [[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
* 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
 


[[Category:ASM]]
[[Category:ASM]]
[[Category:65c816 additions]]
[[Category:65c816 additions]]
[[Category:Unconditional Branches]]
[[Category:One-byte Instructions]]
[[Category:Single Admode Mnemonics]]

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.

rtl.png

See Also

External Links