showText:
    xor a
    ld (show_offset), a
    call renderTextScreen
showTxLp:
    call txControls
    dup 5
    halt
    edup
    jp showTxLp

txControls:
    call inkey
    
    and a
    ret z

    cp 'q'
    jp z, txUp

    cp 'a'
    jp z, txDn

    cp 'b'
    jp z, historyBack

    cp 'o'
    jp z, openURI

    ret

txUp:
    ld a, (show_offset)
    and a
    ret z

    sub 20
    ld (show_offset), a
    call renderTextScreen
    ret

txDn:
    ld a, (show_offset)
    add 20
    ld (show_offset), a
    call renderTextScreen
    ret

renderTextScreen:
    call renderHeader
    ld b, 20
txRenderLp:
    push bc
    ld a, 20
    sub b
    ld b, a
    ld a, (show_offset)
    add b
    ld b, a 
    call renderTextLine
    pop bc
    djnz txRenderLp
    ret


renderTextLine:
    call findLine
    
    ld a, h
    or l
    ret z

    ld a, (hl)
    and a
    ret z
    call printL64
    call mvCR
    ret