RTL: Difference between revisions

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.

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

@@ Line 36: / Line 36: @@
 '''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.
@@ Line 45: / Line 47: @@
 RTL works even in [[emulation mode]], but it is intended primarily for native mode.
+[[File:rtl.png]]
 === See Also ===