; c64view -- multicolor (Koala) bitmap viewer (self-contained)
;
; The picture data is appended to this program by the exporter and loads in one
; pass, so no second disk access is needed.  Fixed memory layout after load:
;   $0801 this program  (BASIC stub + ML, padded up to $2000)
;   $2000 bitmap 8000   (VIC reads here directly)
;   $3F40 screen 1000   (copied to $0400)
;   $4328 colram 1000   (copied to $D800)
;   $4710 background 1
;
; assembled by viewer/assemble.py via xa

        ; BASIC autostart, SYS 2061
        * = $0801
        .word basicend
        .word 10
        .byte $9e
        .byte "2061"
        .byte 0
basicend:
        .word 0                   ; ML begins at $080D

SRC = $fb
DST = $fd

start:
        lda #$0b
        sta $d011                 ; blank screen during setup

        ; copy screen RAM  $3F40 -> $0400
        lda #$40
        sta SRC
        lda #$3f
        sta SRC+1
        lda #$00
        sta DST
        lda #$04
        sta DST+1
        jsr copy1024

        ; copy colour RAM  $4328 -> $D800
        lda #$28
        sta SRC
        lda #$43
        sta SRC+1
        lda #$00
        sta DST
        lda #$d8
        sta DST+1
        jsr copy1024

        ; program the VIC-II
        lda $dd00
        ora #$03
        sta $dd00                 ; VIC bank 0 ($0000-$3FFF)
        lda $4710
        sta $d021                 ; background colour
        lda #$00
        sta $d020                 ; border black
        lda #$18
        sta $d018                 ; screen $0400, bitmap $2000
        lda #$d8
        sta $d016                 ; multicolor mode on
        lda #$3b
        sta $d011                 ; bitmap mode, display on
        lda #$ff
        sta $cc                   ; disable cursor blink

waitkey:
        jsr $ffe4                 ; GETIN
        beq waitkey

        ; restore text mode and return to BASIC
        lda #$1b
        sta $d011
        lda #$c8
        sta $d016
        lda #$15
        sta $d018
        lda #$00
        sta $cc
        jsr $e544                 ; clear screen
        rts

; copy 1024 bytes from (SRC) to (DST)
copy1024:
        ldx #4
        ldy #0
cploop:
        lda (SRC),y
        sta (DST),y
        iny
        bne cploop
        inc SRC+1
        inc DST+1
        dex
        bne cploop
        rts