SixtyPical/eg/demo.60pical

assign byte table screen 1024
assign byte table screen2 1274
assign byte table screen3 1524
assign byte table screen4 1774

assign byte table colormap 55296
assign byte table colormap2 55546
assign byte table colormap3 55796
assign byte table colormap4 56046

assign byte vic_border 53280
assign byte table vic_bg 53281

assign vector cinv 788
reserve vector save_cinv

routine main {
    lda #5
    sta vic_border
    lda #0
    sta vic_bg
    jsr clear_screen
    sei {
        copy vector cinv to save_cinv
        copy routine our_cinv to cinv
    }
    clc
    repeat bcc { }
}

routine our_cinv {
    inc screen
    jmp save_cinv
}

routine clear_screen {
    ldy #0
    repeat bne {
        lda #1
        sta colormap, y
        sta colormap2, y
        sta colormap3, y
        sta colormap4, y
        
        lda #32
        sta screen, y
        sta screen2, y
        sta screen3, y
        sta screen4, y

        iny
        cpy #250
    }
}