4cade/src/demo/pitfall.ii.a

78 lines
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;license:MIT
;(c) 2021 by Frank M.
!cpu 6502
!to "res/DEMO/PITFALL.II",plain
*=$300
!source "src/constants.a" ; no code in these
!source "src/macros.a"
+GAME_REQUIRES_JOYSTICK
+READ_RAM2_WRITE_RAM2
jsr EnableAccelerator
+LOAD_FILE_AT title, $00
lda #$60
sta $3D34
jsr $0800 ; decompress
+RESET_VECTOR reset
lda #$4C
sta $2DF5
sta $2E06
lda #<callback1
sta $2DF6
lda #>callback1
sta $2DF7
lda #<callback2
sta $2E07
lda #>callback2
sta $2E08
+DISABLE_ACCEL
jmp $6000 ;612A copies pages 2E & 2F to AE & AF for final location
reset
+READ_RAM2_NO_WRITE
jmp ($FFFC)
callback1
sec
sbc #8
cmp #2
bcc +
- jmp $AE0A
+ jmp $ADF9
callback2
ldx #6-1
p1 lda patch, x
sta $6055, x
sta $AB43, x
dex
bpl p1 ; set demo exits
lda #$BF
sta $6021 ; reduce time before demo starts
lda #$D0
sta $6299 ; don't lose keypress on return
sec
sbc #8
cmp #2
bcs -
jmp $AE21
patch !byte $AD,$88,$C0,$6C,$FC,$FF
title !byte x_e-x_b
x_b !text "X/PITFALL.II/PITFALL.II"
x_e
!if * > $3F0 {
!error "code is too large, ends at ", *
}