registers

A program of Targets.

main.ngp

target {
  region          $0080 .. $00FF  ram
  region          $2000 .. $BFFF  ram

; tag registers
  region COLBK    $D01A .. $D01A  register
  register COLPF2 $D018
  register WSYNC  $D40A
  register VCOUNT $D40B
; end registers
}

modules { "rainbow.asm" }

container xex

rainbow.asm

.proc entry
@top    lda VCOUNT
        jne @top

        ldx #0
@line   sta WSYNC
        stx COLBK
        stx COLPF2
        inx
        cpx #240
        jcc @line

        jmp @top
.endp

Memory map

1. phase00 zero page, 24 bytes

The xex

36 bytes, 2 segments, 0 unaccounted.