; autorun.s - display an intro screen and a menu from which the user
; can launch dla.xex or dla2csv.xex, or exit to DOS.

; I was *going* to write this in C, using cc65's exec()... but it
; turns out to only be implemented on XDOS, which is a rather uncommon
; DOS. MyDOS has XIO 40 (execute binary file), which is a lot easier
; to deal with in asm. Other DOSes might support XIO 40, and/or this
; might support other DOSes someday... Or I could write my own xex
; file loader (rather not).

 .include "atari.inc"
 .include "xex.inc"

 .bss
 .org $80

old_sdlstl: .res 1
old_sdlsth: .res 1
old_color2: .res 1
old_color1: .res 1
keycode:    .res 1

 .code

 ; this doesn't have to be aligned on a 4K boundary, but it should
 ; be aligned to 1K.
loadaddr = $3000

 xex_org loadaddr
screendata:
 .incbin "about.dat" ; generated from ABOUT.txt, by text2screen.pl

 ; 960 bytes is exactly one GR.0 screen (40x24)
 .if ((* - screendata) <> 960)
   .error .sprintf("%c*** about.dat is %d bytes (should be 960)", 10, * - screendata)
 .endif

 ; bog-standard GRAPHICS 0 display list (except the LMS address)
dlist:
 .byte DL_BLK8, DL_BLK8, DL_BLK8
 .byte DL_CHR40x8x1 | DL_LMS
 .word screendata
 .repeat 23
  .byte DL_CHR40x8x1
 .endrep
 .byte DL_JVB
 .word dlist

 .if ((* / 1024) <> (screendata / 1024))
  .error .sprintf("%c*** screendata and dlist cross a 1K boundary!", 10)
 .endif

 .include "io.s"
 .include "printint.s"

main:
 ; fix things so the Reset key doesn't do a coldstart, see
 ; BOOT? and COLDST in Mapping.
 ldx #0
 stx COLDST
 inx
 stx BOOTQ

 ; save the OS's colors and display list.
 lda SDLSTL
 sta old_sdlstl
 lda SDLSTH
 sta old_sdlsth
 lda COLOR1
 sta old_color1
 lda COLOR2
 sta old_color2

 ; use our own colors and display list (displays our message).
 lda #$90
 sta COLOR2
 lda #$0e
 sta COLOR1
 lda #<dlist
 sta SDLSTL
 lda #>dlist
 sta SDLSTH

 ; wait for a keypress
keyloop:
 lda CH
 cmp #KEY_NONE
 beq keyloop

 sta keycode ; got a keypress, save it for later

 ; clear keypress so the loaded program won't see it
 lda #$ff
 sta CH

 ; restore OS's colors and display list (back to regular E:)
 lda old_sdlstl
 sta SDLSTL
 lda old_sdlsth
 sta SDLSTH
 lda old_color1
 sta COLOR1
 lda old_color2
 sta COLOR2

 ; see what key was hit
 ldy #0
keytabloop:
 lda keytab,y   ; get table entry
 cmp #KEY_NONE  ; did we hit the end of the table with no match?
 beq exit       ; yes, we're done
 cmp keycode    ; no, see if this table entry matches
 beq load_file  ; yes, use it
 iny            ; no, look at next entry
 bne keytabloop ; branch always

 ; load and run the file (Y is index into filename table)
load_file:
 ldx #$10 ; IOCB #1
 lda #$28 ; MyDOS XIO 40. 39 also works (same thing?), neither works on SDX
 sta ICCOM,x
 lda fntab_l,y  ; filename
 sta ICBAL,x
 lda fntab_h,y
 sta ICBAH,x
 lda fnlentab,y ; filename length
 sta ICBLL,x
 lda #0
 sta ICBLH,x
 jsr CIOV       ; pull the trigger

 ; CIOV should never return on success, so if we get here, give up.
 tya
 pha ; save CIO return status (aka error number)
 lda #<diskerrmsg
 ldx #>diskerrmsg
 jsr printmsg ; print error message
 pla
 jsr printdecb ; print error number
 lda #<presskeymsg
 ldx #>presskeymsg
 jsr printmsg  ; press a key...

 ; wait for a keypress, to give the user a chance to read the
 ; error message.
keyloop2:
 lda CH
 cmp #KEY_NONE
 beq keyloop2
 lda #KEY_NONE
 sta CH
exit:
 rts

dla_filename: .byte "D:DLA.XEX"
dla_fn_len = * - dla_filename

csv_filename: .byte "D:DLA2CSV.XEX"
csv_fn_len = * - csv_filename

; these tables only have 2 entries, but could have many more if
; we ever need them (up to 255).
fntab_l:  .byte <dla_filename, <csv_filename
fntab_h:  .byte >dla_filename, >csv_filename

fnlentab: .byte dla_fn_len, csv_fn_len

; KEY_NONE marks the end of this table.
keytab: .byte KEY_1, KEY_2, KEY_NONE

diskerrmsg:  .byte "I/O Error ",0
presskeymsg: .byte $9b,"Press any key...",0

xex_run main