%import textio
%zeropage dontuse
%option no_sysinit

main {

;   $1F9C0 - $1F9FF 	PSG registers

    sub start() {
        c64.set_rasterirq(&irq.irq, 100, true)

        sys.wait(100)

        c64.restore_irq()

;        uword freq = 1181
;        cx16.vpoke(1, $f9c0, lsb(freq))
;        cx16.vpoke(1, $f9c1, msb(freq))
;        cx16.vpoke(1, $f9c2, %11111111)     ; volume
;        cx16.vpoke(1, $f9c3, %11000000)     ; triangle waveform
    }
}


irq {
    uword counter = 0

    sub irq() {
        c64.EXTCOL++
        ubyte xx
        repeat 20 {
            xx++
        }
        c64.EXTCOL--

        @($0400) = lsb(counter)
        @($0401) = msb(counter)

        counter++
    }
}