4cade/src/demo/robotron.a

;license:MIT
;(c) 2021-2022 by Frank M., qkumba

!cpu 6502
!to "build/DEMO/ROBOTRON.2084#069000",plain
*=$9000

         !source "src/constants.a"   ; no code in these
         !source "src/macros.a"

         +ENABLE_ACCEL_LC
         +LOAD_XSINGLE title

         lda   #<callback
         sta   $141D+1
         lda   #>callback
         sta   $141D+2
         jmp   $1400      ; decompress

callback ldx   #6-1
-        lda   $100, x
         sta   $4542, x
         dex
         bpl   -          ; exit on keypress

         ldx   #3-1
-        lda   patch, x
         sta   $453A, x
         dex
         bpl   -          ; exit at end of demo cycle

         lda   #$D0
         sta   $053B      ; disable sound

         +DISABLE_ACCEL

         jmp   $4015

patch    !byte $4C,$42,$45

title    !byte x_e-x_b
x_b      !text "ROBOTRON.2084"
x_e

!if * > $C000 {
  !error "code is too large, ends at ", *
}