8x16 scroll gravity 2017

#import "helpers.asm"
BasicUpstart2(mainProg)

.const scrollLine = $0400+23*40

            *=$1000

mainProg:   {
            sei

            lda $d018
            ora #%00001110
            sta $d018

            // Wait for line $f2 and set d016
loop1:      lda #$e9
            cmp $d012
            bne loop1
            jsr setScrollD016


loop2:      lda #$ff
            cmp $d012
            bne loop2
            lda #$c8
            sta $d016
            jsr moveScroll

            jmp loop1
}
//----------------------------------------------------
//          Scroll Routines
//----------------------------------------------------

setScrollD016:  {
value:      lda #0
            and #$07
            ora #$c0
            sta $d016
            rts
}

moveScroll: {
            // Step d016
            dec setScrollD016.value+1
            lda setScrollD016.value+1
            and #$07
            cmp #$07
            bne exit

            // Move screen chars
            ldx #0
loop1:      lda scrollLine+1,x
            sta scrollLine,x
            inx
            clc
            adc #64
            sta scrollLine+39,x
            cpx #39
            bne loop1

            // Print new char
count:      ldx #0
            lda text,x
            sta scrollLine+39
            inx
            lda text,x
            cmp #$ff
            bne over1
            ldx #0
over1:      stx count+1

exit:       rts

text:       .text "scroll zrobiony na gravity 2017 wsrod krwiozerczych atarowcow. michal dlubie gre o zebrach a ja mam 8x16 font scroll.... umiem wyswietlac i skrolowac duze fonty!!! huraaaa                          "
            .byte $ff
}


.pc = $3800 "Font 1"
.import c64 "8x16font