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Stack: Difference between revisions

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(buffers category)
(more push/pull instructions)
Line 14: Line 14:
* [[PHX]]
* [[PHX]]
* [[PHY]]
* [[PHY]]
* [[JSR]]
* [[JSL]]


Pulling takes one cycle more than pushing.  These instructions pull things from the stack:
PL* instructions take one cycle more than their PH* counterparts.  These instructions pull things from the stack:


* [[PLA]]
* [[PLA]]
Line 23: Line 25:
* [[PLX]]
* [[PLX]]
* [[PLY]]
* [[PLY]]
* [[RTS]]
* [[RTL]]
* [[RTI]]


Note the lack of [[PLK]].  PHS and PLS similarly do not exist.
Note the lack of [[PLK]].  PHS and PLS similarly do not exist.

Revision as of 02:19, 11 August 2024

The Stack is a buffer which remembers the state of subroutines that are currently executing.

On the 65c816, the stack is always in bank zero.[3] It can be thousands of bytes deep.[1]

In emulation mode it wraps within page one.[2]

The stack grows towards zero, but the most recently pushed byte is nontheless called the top of the stack. These instructions push things to the stack:

PL* instructions take one cycle more than their PH* counterparts. These instructions pull things from the stack:

Note the lack of PLK. PHS and PLS similarly do not exist.

See Also

References

  1. Wilson, Garth. https://wilsonminesco.com/816myths
  2. Clark, Bruce. http://www.6502.org/tutorials/65c816opcodes.html#5.1.1
  3. section 2.11 of 65c816 datasheet: https://www.westerndesigncenter.com/wdc/documentation/w65c816s.pdf