;Implementation of SoftMMU - skeleton expansion code
;===================================================

;In this file, we implement every routine defined in
;sm.skeleton.h, except for init and author.  Remember
;that this file is #included along with all the other
;expansions, so keep label names unique by including
;the expansion name in the label name.

;tsp_exp is defined, before #including this file, as
;        the offset into the TSP where the expansion-
;        specific bytes have been reserved.

;----
;Name
;----

;Not a routine, just some short identifying text.
;(zero terminated)

name_skeleton:
.byte "Sample",$00

;----------
;Allocation
;----------

xalloc_skeleton:

;For normal expansions, the xalloc routine simply
;queries the free list page and takes care of the
;actual allocation. If xalloc_expansion is not
;$00xx, it is called after the expansion is successfully
;performed, for whatever purpose you may need.
;<- .X = memory expansion number (preserve it on exit!)
;-> nothing

;If no free list page is allocated, xalloc_expansion
;must perform the actual allocation & related book
;keeping.
;<- .X = memory expansion number (preserve it on exit!)
;-> c=1 allocation failed
;-> c=0 allocation successful

;------------
;Deallocation
;------------

xfree_skeleton:

;Called under the same conditions as xalloc_expansion.
;So if you use free list pages, usually this routine will
;be unnecessary.  If you don't, you must implement the
;entire deallocation here.

;------------
;Reallocation
;------------

xrealloc_skeleton:

;not yet implemented

;---------
;Page swap
;---------

xpage_skeleton:

;Perform a page swap, by whatever expansion-specific
;method you want.  Since this will be the most called
;routine, get it as fast as you can.

;<- .Y = memory expansion number
;<- .X = zp pointer to user structure (window,page)
;<- interrupts are disabled.
;<- tmpzp+2 = page offset into the expansion that
;             you need to get into addressable RAM.
;             This value is guaranteed to be valid.
;
;-> MUST exit with pla:tya:pla:rts with .X preserved
;   and interrupts enabled.

;If the paging routine takes a long time, cli and
;call locktsw.  Obviously, make sure to unlocktsw
;before returning.

;----------------
;Context Switches
;----------------

;These are especially useful for banked memory systems,
;because changing the memory state will usually affect
;the entire base address space.  These are only called
;if sm_setmygetcontextbit or sm_setmylosecontextbit
;have been called by some other function, and can be
;disabled by calling sm_clearmygetcontextbit or
;sm_clearmylosecontextbit.

getcontext_skeleton:
losecontext_skeleton: