;license:MIT
;(c) 2018-2021 by 4am & qkumba
;
; ProRWTS2 glue functions
;
; Public functions
; - LoadFile
; - LoadAuxFile
; - LoadDHRFile
; - LoadIndexedFile
;
; Public variables
; - gRootDirectory
;
; A general note about paths:
;
; Load[*]File routines support subdirectories. Directories are delimited by '/'
; like ProDOS. At program startup, we get the current directory and save it;
; that is the PROGRAM ROOT DIRECTORY. All pathnames are relative to the PROGRAM
; ROOT DIRECTORY. There is no concept of setting or changing the 'current'
; directory.
;
; The PROGRAM ROOT DIRECTORY is not guaranteed to be the root directory of the
; underlying ProDOS disk (although it can be). But it doesn't matter, because
; these functions provide no access to any directory above the PROGRAM ROOT
; DIRECTORY. You can't use '..' to access the parent directory, and you can't
; start a pathname with '/' to access the root directory of the underlying
; ProDOS disk.
;
; Examples:
; 'PREFS.CONF' points to a file named 'PREFS.CONF' in the PROGRAM ROOT
; DIRECTORY.
;
; 'FX/RIPPLE' points to a file named 'RIPPLE' in a directory named 'FX' in the
; PROGRAM ROOT DIRECTORY.

;------------------------------------------------------------------------------
; LoadFile
; Load a file into memory all at once, using ProRWTS2
;
; supports paths, see note
;
; in:    stack contains 6 bytes of parameters:
;          +1 [word] address of length-prefixed pathname
;          +3 [word] address of length-prefixed filename
;          +5 [word] address to load file, or 0 to use file's default address
; out:   all flags clobbered
;        all registers clobbered
;        gPathname clobbered
;------------------------------------------------------------------------------
LoadFile
         +PARAMS_ON_STACK 6
         +LDPARAM 1
         jsr   SetPath
         +LDPARAM 3
         jsr   AddToPath
         +LDPARAMPTR 5, ldrlo        ; set load address
         jsr   SwitchToBank2
         jsr   LoadFileInternal
         jmp   SwitchToBank1

;------------------------------------------------------------------------------
; LoadAuxFile
; Load a file into aux memory all at once, using ProRWTS2
;
; supports paths, see note
;
; in:    stack contains 6 bytes of parameters:
;          +1 [word] address of length-prefixed pathname
;          +3 [word] address of length-prefixed filename
;          +5 [word] address to load file, or 0 to use file's default address
; out:   all flags clobbered
;        all registers clobbered
;        gPathname clobbered
;------------------------------------------------------------------------------
LoadAuxFile
         +PARAMS_ON_STACK 6
         +LDPARAM 1
         jsr   SetPath
         +LDPARAM 3
         jsr   AddToPath
         +LDPARAMPTR 5, ldrlo        ; set load address
         jsr   SwitchToBank2
         lda   #1                    ; request aux memory
         jsr   LoadFileAuxInternal
         jmp   SwitchToBank1

;------------------------------------------------------------------------------
; LoadDHRFile
; load .A2FC file (uncompressed double hi-res graphics) into memory
; all at once, using ProRWTS2
; first $2000 bytes of file are loaded into auxiliary memory $4000..$5FFF
; second $2000 bytes of file are loaded into main memory $4000..$4FFF
;
; supports paths, see note
;
; in:    stack contains 4 bytes of parameters:
;          +1 [word] address of length-prefixed pathname
;          +3 [word] address of length-prefixed filename
; out:   all flags clobbered
;        all registers clobbered
;        stack set to next instruction after parameters
;------------------------------------------------------------------------------
LoadDHRFile
         +PARAMS_ON_STACK 4
         +LDPARAM 1
         jsr   SetPath
         +LDPARAM 3
         jsr   AddToPath
         jsr   SwitchToBank2
         jsr   LoadDHRFileInternal
         jmp   SwitchToBank1

;------------------------------------------------------------------------------
; LoadIndexedFile
; Load a file from inside an indexed file, all at once
;
; To save disk space, some collections of small, related files (e.g. per-game
; help files) are merged into a single data file with an associated index file.
; The index stores the original filename along with an offset (into the merged
; data file) and a length.
;
; Callers are responsible for loading the index file and finding the relevant
; record within the index. Most callers use okvs_find() for this.
;
; in:    stack contains 6 bytes of parameters:
;          +1 [word] pointer to filename of merged data file
;          +3 [word] address of load destination
;          +5 [word] pointer to index record (see note)
; out:   all flags clobbered
;        all registers clobbered
;------------------------------------------------------------------------------
LoadIndexedFile
         +PARAMS_ON_STACK 6
         +LDPARAM 1
         +ST16 @filename
         +LDPARAM 3
         +ST16 @address
         +LDPARAM 5
         +ST16 zpword
         inc   $BF0E                 ; disable ROM mapping on return
         ldx   #2
         ldy   #0
         lda   (zpword), y
         tay
-        iny
         lda   (zpword), y
         sta   @offset, x
         dex
         bpl   -
         dex
-        iny
         lda   (zpword), y
         sta   @size - $fe, x
         inx
         bmi   -
         jsr   $bf00                 ; yes, ProDOS abstraction
         !byte $c8
         !word @c8_parms
         jsr   $bf00
         !byte $ce
         !word @ce_parms
         jsr   $bf00
         !byte $ca
         !word @ca_parms
         jsr   $bf00
         !byte $cc
         !word @cc_parms
         dec   $BF0E                 ; re-enable ROM mapping on return
         jmp   SwitchToBank1

@c8_parms
         !byte 3
@filename
         !word $DFDF                 ; SMC
         !byte 0
@ce_parms
         !byte $d0
         !byte 1
@offset  !byte 0, 0, 0               ; SMC
         !byte $ff
@ca_parms
         !byte $ff
@cc_parms
         !byte 1
@address !word $DFDF                 ; SMC
@size    !word $DFDF                 ; SMC
         !word $ffff

gRootDirectory
         !word $FDFD