scroll simple

:BasicUpstart2(main)

//----------------------------------------------------------
// Code for creating the breakpoint file sent to Vice.
//----------------------------------------------------------
.var _useBinFolderForBreakpoints = cmdLineVars.get("usebin") == "true"
.var _createDebugFiles = cmdLineVars.get("afo") == "true"
.print "File creation " + [_createDebugFiles
    ? "enabled (creating breakpoint file)"
    : "disabled (no breakpoint file created)"]
.var brkFile
.if(_createDebugFiles) {
    .if(_useBinFolderForBreakpoints)
        .eval brkFile = createFile("bin/breakpoints.txt")
    else
        .eval brkFile = createFile("breakpoints.txt")
}
.macro break() {
.if(_createDebugFiles) {
    .eval brkFile.writeln("break " + toHexString(*))
    }
}
//------------------------------------------------------
main:
:ClearScreen($0400,32)


   sei

start:
     lda #$3b  //; wait for line #59, making sure we
!jump:
    cmp $d012 //; don't catch it twice in one frame
    beq !jump-
 !jump:
        cmp $d012
        bne !jump-

 lda $d016 //; decrease scroll register
 sbc #$01  //; (carry was set by cmp above)
 and #$07
 sta $d016
 cmp #$07  //; go back if there's no need
 bne start //; to shift screen memory

 ldx #$00  //; move columns 1..38 one byte left
screen: lda $0401,x
 sta $0400,x
 inx
 cpx #$26
 bne screen

 lda $c000 //; some dummy data to column 38
 sta $0426
 inc *-5

 jmp start

* = $c000 "Tekst"
.text "arek arek arek"
raster_color:
    .byte $00,$00,$07,$0a,$08,$0a,$08,$02
    .byte $08,$02,$09,$02,$09,$0b,$09,$0b
    .byte $00,$0b,$00,$07,$0a,$08,$0a,$08
    .byte $02,$08,$02,$09,$02,$09,$0b,$09
    .byte $0b,$00,$0b,$00,$08,$0a,$08,$02
    .byte $08,$02,$09,$02,$09,$0b,$09,$0b
    .byte $00,$0b,$00,$08,$02,$08,$02,$09
    .byte $02,$09,$0b,$09,$0b,$00,$0b,$00
    .byte $08,$02,$09,$02,$09,$0b,$09,$0b
    .byte $00,$0b,$00,$09,$02,$09,$0b,$09
    .byte $0b,$00,$0b,$00,$09,$0b,$09,$0b
    .byte $00,$0b,$00,$09,$0b,$00,$0b,$00
    .byte $00,$0b,$00,$00,$0b,$00,$00,$0b
    .byte $00,$0b,$06,$00,$0b,$00,$0b,$06
    .byte $0b,$06,$00,$0b,$00,$0b,$06,$0b
    .byte $06,$0c,$06,$00,$0b,$00,$0b,$06
    .byte $0b,$06,$0c,$06,$0c,$0e,$00,$0b
    .byte $00,$0b,$06,$0b,$06,$0c,$06,$0c
    .byte $0e,$0c,$0e,$00,$0b,$00,$0b,$06
    .byte $0b,$06,$0c,$06,$0c,$0e,$0c,$0e
    .byte $0f,$0e,$00,$0b,$00,$0b,$06,$0b
    .byte $06,$0c,$06,$0c,$0e,$0c,$0e,$0f
    .byte $0e,$0f,$03,$00,$0b,$00,$0b,$06
    .byte $0b,$06,$0c,$06,$0c,$0e,$0c,$0e
    .byte $0f,$0e,$0f,$03,$0f,$03,$00,$0b
    .byte $00,$0b,$06,$0b,$06,$0c,$06,$0c
    .byte $0e,$0c,$0e,$0f,$0e,$0f,$03,$0f
    .byte $03,$01,$00,$00,$00,$00,$00,$00
    .byte $00,$00,$00,$00,$00,$00,$00,$00
    .byte $00,$00,$00,$00,$00,$00,$00,$00


.macro ClearScreen(screen, clearByte) {
    lda #clearByte
    ldx #0
!loop:
    sta screen, x
    sta screen + $100, x
    sta screen + $200, x
    sta screen + $300, x
    inx
    bne !loop-
}

.pseudocommand pause cycles {
    :ensureImmediateArgument(cycles)
    .var x = floor(cycles.getValue())
    .if (x<2) .error "Cant make a pause on " + x + " cycles"

    // Take care of odd cyclecount
    .if ([x&1]==1) {
        bit $00
        .eval x=x-3
    }

    // Take care of the rest
    .if (x>0)
        :nop #x/2
}


//---------------------------------
// repetition commands
//---------------------------------
.macro ensureImmediateArgument(arg) {
    .if (arg.getType()!=AT_IMMEDIATE)   .error "The argument must be immediate!"
}
.pseudocommand asl x {
    :ensureImmediateArgument(x)
    .for (var i=0; i<x.getValue(); i++) asl
}
.pseudocommand lsr x {
    :ensureImmediateArgument(x)
    .for (var i=0; i<x.getValue(); i++) lsr
}
.pseudocommand rol x {
    :ensureImmediateArgument(x)
    .for (var i=0; i<x.getValue(); i++) rol
}
.pseudocommand ror x {
    :ensureImmediateArgument(x)
    .for (var i=0; i<x.getValue(); i++) ror
}

.pseudocommand pla x {
    :ensureImmediateArgument(x)
    .for (var i=0; i<x.getValue(); i++) pla
}

.pseudocommand nop x {
    :ensureImmediateArgument(x)
    .for (var i=0; i<x.getValue(); i++) nop
}

teskt:
    .byte $04