4cade/src/prelaunch/nightmare.a

;license:MIT
;(c) 2020, 2022 by Frank M., qkumba

!cpu 6502
!to "build/PRELAUNCH.INDEXED/NI",plain
*=$106

    !source "src/prelaunch/common.a"

         +ENABLE_ACCEL
         +NEW_RESET_VECTOR $BE00

         lda   #$60
         sta   $404B
         jsr   $4000      ; decompress

         ldx   #(callback_e-callback)-1
-        lda   callback,x
         sta   $BE20,x
         dex
         bpl   -
         lda   #$20       ; lets fix ROM calls to WAIT/$FCA8
         sta   $16A9      ; which behave differently
         sta   $80EE      ; on different machines
         sta   $8799      ; (fixes slow scream on //c+ & //gs)
         sta   $8C8F
         sta   $8CC4
         sta   $8CE1
         lda   #$BE
         sta   $16AA
         sta   $80EF
         sta   $879A
         sta   $8C90
         sta   $8CC5
         sta   $8CE2

         +READ_RAM2_NO_WRITE
         lda   MachineStatus
         and   #CHEATS_ENABLED
         beq   +
         lda   #$AD
         sta   $8718      ; patch - don't decrease lives
         sta   $8980      ; patch - don't increase lives
+
         jsr   DisableAccelerator
         +READ_ROM_NO_WRITE
         jmp   $1206

callback sec              ; non-ROM WAIT
wait2    pha
wait3    sbc   #$01
         bne   wait3
         pla
         sbc   #$01
         bne   wait2
         rts
callback_e

!if * > $1C0 {
  !error "code is too large, ends at ", *
}