4cade/src/demo/gremlins.a

;license:MIT
;(c) 2022 by qkumba

!cpu 6502
!to "build/DEMO/GREMLINS#06BE00",plain
*=$be00

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

         +ENABLE_ACCEL_LC
         +LOAD_XSINGLE title

         lda   #$4C
         sta   $082D
         sta   $0863
         lda   #$2C
         sta   $839       ; no music
         lda   #0
         sta   $856       ; exit keycheck sooner
         jsr   $0800      ; decompress

         +DISABLE_ACCEL

         jsr   $830       ; check key
         bit   $C000
         bmi   patch
         ldx   #0
         stx   $5219      ; exit keycheck sooner
         ldx   #3-1
-        lda   patch,x
         sta   $51F2,x
         sta   $5505,x
         sta   $61E4,x
         dex
         bpl   -
         jmp   $4000

patch    !byte $4C,$00,$01

title    !byte x_e-x_b
x_b      !text "GREMLINS"
x_e

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