require'vcs'

-- change this if for some reason it fails to link
-- space for 10 song pointers
local FREESPACE = 3759-10*2

#pragma encapsulate far farcall
#pragma alias and dna

mappers.F4()
rom0.name = "core"

do
    local ram = {
        { tt_timer=1 },
        { tt_cur_pat_index=2 },
        { tt_cur_note_index=2 },
        { tt_envelope_index=2 },
        { tt_cur_ins=2 },
        { tt_ptr = \(tmp) },
        { tt_song = \(tmp+2) },
        { tt_ptrtab = \(tmp+4) },

        { tt_song_ix=1 },           -- index into song_table
        { tt_song_ix_next=1 },      -- queued song to play after fade out
        { song_delay=1 },           -- fade out timer
        { cur_song_ix=1 },          -- current song index, cached
        { input_prev=1 },           -- previous SWCHA 4 MSB (player 0) value >> 1 | INPT4 MSB (fire player 0)

        { AUDC0s=1 }, { AUDC1s=1 }, { AUDF0s=1 }, { AUDF1s=1 }, { AUDV0s=1 }, { AUDV1s=1 },
        { vubars=16 },

        { tmp=30 },

        { print_txt = \(tmp+1) },         -- text pointer, can cross
        { print_line_count = \(tmp) },    -- number of lines to print
        { print_ptr = \(tmp+3) },         -- array of pointers to the characters
    }

    local ad = 0x80
    for k,v in ipairs(ram) do
        local f,t = pairs(v)
        k,v = f(t)
        if type(v) ~= 'function' then
            _ENV[k] = ad
            ad = ad + v
        end
    end
    assert(ad <= 0x100)
    for k,v in ipairs(ram) do
        local f,t = pairs(v)
        k,v = f(t)
        if type(v) == 'function' then _ENV[k] = v() end
        symbols[k] = _ENV[k]
    end
end

-- 30 bytes fixed per song
TT_INSCTRLTABLE         = 0
TT_INSADINDEXES         = 2
TT_INSSUSTAININDEXES    = 4
TT_INSRELEASEINDEXES    = 6
TT_INSFREQVOLTABLE      = 8
TT_PERCINDEXES          = 10
TT_PERCFREQTABLE        = 12
TT_PERCCTRLVOLTABLE     = 14
TT_PATTERNSPEEDS        = 16
TT_SEQUENCETABLE        = 18
TT_PATTERNPTRLO         = 20
TT_PATTERNPTRHI         = 22
TT_PTR_SZ               = 24
TT_GLOBAL_SPEED         = 0+TT_PTR_SZ
TT_SPEED                = 1+TT_PTR_SZ
TT_ODD_SPEED            = 2+TT_PTR_SZ
TT_USE_FUNKTEMPO        = 3+TT_PTR_SZ
TT_C0INIT               = 4+TT_PTR_SZ
TT_C1INIT               = 5+TT_PTR_SZ

TT_FREQ_MASK    = 0b00011111
TT_INS_HOLD     = 8
TT_INS_PAUSE    = 16
TT_FIRST_PERC   = 17

-- far calls to players to generate the stubs - the section will be stripped as it's unreferenced
location(rom0)
local sec_farstubgen = section("farstubsgen")

-- full ttt player with all possible options active, one for each rom bank but 0
for i=1,7 do
    local loc = location(_ENV['rom'..i])
    loc.songs_lo,loc.songs_hi = section("songs_lo"..i), section("songs_hi"..i)
    local tt_fetchCurrentNote = section("tt_fetchCurrentNote"..i)
    @_constructPatPtr
            ldy tt_cur_pat_index,x lda (tt_ptrtab+TT_SEQUENCETABLE),y
            bpl _noPatternGoto
            dna #0b01111111 sta tt_cur_pat_index,x bpl _constructPatPtr
    @_noPatternGoto
            tay lda (tt_ptrtab+TT_PATTERNPTRLO),y sta tt_ptr lda (tt_ptrtab+TT_PATTERNPTRHI),y sta tt_ptr+1
            clv
            lda tt_cur_note_index,x bpl _notPrefetched
            dna #0b01111111 sta tt_cur_note_index,x
            bit "bit6Set"..i
    @_notPrefetched
            tay
            lda (tt_ptr),y bne _noEndOfPattern
            sta tt_cur_note_index,x
            inc tt_cur_pat_index,x
            bne _constructPatPtr
    @_noEndOfPattern
            rts

    local tt_CalcInsIndex = section("tt_CalcInsIndex"..i)
            lsr lsr lsr lsr lsr
            tay
    label("bit6Set"..i)
            rts

    loc.tt_tick = section("tt_tick"..i).instructions[1] -- get label table, used as index for far stubs
            lda loc.songs_lo,y sta tt_song lda loc.songs_hi,y sta tt_song+1
            bit tt_timer bpl _nosonginit
            lda #0 sta tt_timer
            ldy #TT_C0INIT lda (tt_song),y sta tt_cur_pat_index iny lda (tt_song),y sta tt_cur_pat_index+1
    @_nosonginit
            ldy #TT_PTR_SZ-1 @_setptrs lda (tt_song),y sta tt_ptrtab,y dey bpl _setptrs
            dec tt_timer bpl _noNewNote
            ldx #1
    @_advanceLoop
            jsr tt_fetchCurrentNote
            cmp #TT_INS_PAUSE
            beq _pause
            bcs _newNote
            adc tt_cur_ins,x sec sbc #8 sta tt_cur_ins,x
            bcs _finishedNewNote
    @_pause
            lda tt_cur_ins,x jsr tt_CalcInsIndex
            lda (tt_ptrtab+TT_INSRELEASEINDEXES),y
            clc adc #1 bcc _storeADIndex
    @_newNote
            sta tt_cur_ins,x
            cmp #TT_FREQ_MASK+1 bcs _startInstrument
            tay
            lda (tt_ptrtab+TT_PERCINDEXES),y
            bne _storeADIndex
    @_startInstrument
            bvs _finishedNewNote
            jsr tt_CalcInsIndex
            lda (tt_ptrtab+TT_INSADINDEXES),y
    @_storeADIndex
            sta tt_envelope_index,x
    @_finishedNewNote
            inc tt_cur_note_index,x
    @_sequencerNextChannel
            dex
            bpl _advanceLoop
            ldy #TT_GLOBAL_SPEED lda (tt_song),y beq _localspeed
            iny lax (tt_song),y
            ldy #TT_USE_FUNKTEMPO lda (tt_song),y beq _globalnofunktempo
            lda tt_cur_note_index lsr bcc _noOddFrame ldy #TT_ODD_SPEED lax (tt_song),y @_noOddFrame
    @_globalnofunktempo
            stx tt_timer
            jmp _speeddone
    @_localspeed
            ldy tt_cur_pat_index lda (tt_ptrtab+TT_SEQUENCETABLE),y tay
            sty tt_ptr ldy #TT_USE_FUNKTEMPO lda (tt_song),y ldy tt_ptr cmp #0 beq _localnofunktempo
            lda tt_cur_note_index lsr
            lda (tt_ptrtab+TT_PATTERNSPEEDS),y
            bcc _evenFrame
            dna #0x0f
            bcs _storeFunkTempo
    @_evenFrame
            lsr lsr lsr lsr
    @_storeFunkTempo
            sta tt_timer
            jmp _speeddone
    @_localnofunktempo
            lda (tt_ptrtab+TT_PATTERNSPEEDS),y sta tt_timer
    @_speeddone
    @_noNewNote
            ldx #1
    @_updateLoop
            lda tt_cur_ins,x
            beq _afterAudioUpdate
            cmp #TT_FREQ_MASK+1 bcs _instrument
            ldy tt_envelope_index,x
            lda (tt_ptrtab+TT_PERCCTRLVOLTABLE),y beq _endOfPercussion inc tt_envelope_index,x @_endOfPercussion
            sta AUDV0s,x lsr lsr lsr lsr sta AUDC0s,x
            lda (tt_ptrtab+TT_PERCFREQTABLE),y
            sta AUDF0s,x
            bpl _afterAudioUpdate
            jsr tt_fetchCurrentNote
            cmp #TT_FREQ_MASK+1
            bcc _afterAudioUpdate
            sta tt_cur_ins,x
            jsr tt_CalcInsIndex
            lda (tt_ptrtab+TT_INSSUSTAININDEXES),y sta tt_envelope_index,x
            asl tt_cur_note_index,x sec ror tt_cur_note_index,x
            bmi _afterAudioUpdate
    @_instrument
            jsr tt_CalcInsIndex
            lda (tt_ptrtab+TT_INSCTRLTABLE),y sta AUDC0s,x
            lda tt_envelope_index,x cmp (tt_ptrtab+TT_INSRELEASEINDEXES),y bne _noEndOfSustain lda (tt_ptrtab+TT_INSSUSTAININDEXES),y @_noEndOfSustain
            tay
            lda (tt_ptrtab+TT_INSFREQVOLTABLE),y beq _endOfEnvelope iny @_endOfEnvelope
            sty tt_envelope_index,x
            sta AUDV0s,x
            lsr lsr lsr lsr clc adc tt_cur_ins,x sec sbc #8
            sta AUDF0s,x
    @_afterAudioUpdate
            dex
            bpl _updateLoop
            rts

    section(sec_farstubgen) far loc.tt_tick

end

-- set free size in each location
location(rom0)
local songs_meta_lo,songs_meta_hi = section("songs_meta_lo"),section("songs_meta_hi")
local locsz = {}
for lix,loc in ipairs(locations) do
    if loc ~= rom0 then 
        location(rom0)
        local secmeta = section("songs"..lix.."_meta")
        section(songs_meta_lo) byte_lo(secmeta)
        section(songs_meta_hi) byte_hi(secmeta)
        table.insert(locsz, { lix=lix, secmeta=secmeta, space=FREESPACE })
    end
end

-- load all songs
local songs = {}
do
    local lfs = require'lfs'
    local dir = ... or lfs.currentdir()
    for file in lfs.dir(dir) do
        if file:sub(-4) == '.ttt' then
            local song = ttt(dir .. '/' .. file)
            table.insert(songs, song)
            local size = 0
            for _,v in pairs(song) do
                if type(v) == 'table' then
                    if type(v[1]) == 'table' then
                        for _,vv in ipairs(v) do size = size + #vv end
                    else
                        size = size + #v
                    end
                end
            end
            size = size + 2*#song.patterns -- pattern pointers
            song.size = size + 30
            song.filename = file:sub(1,-5)
        end
    end
end

-- place all songs
charset(" abcdefghijklmnopqrstuvwxyz", \x(x*8))
local meta = function(txt)
    txt = txt:lower()
    local out = {}
    for i=1,#txt do
        local c = string.byte(txt:sub(i,i))
        if c < string.byte('a') or c > string.byte('z') then c = string.byte(' ') end
        table.insert(out, string.char(c))
    end
    for i = 1, 12-#out do
        if i&1 ~= 0 then table.insert(out, 1, ' ')
        else table.insert(out, ' ')
        end
    end
    return table.concat(out):sub(1,12)
end
local song_ids = {} -- 4 LSB: song index, 4 MSB: bank index
table.sort(songs, \a,b(a.size > b.size))
for _,song in ipairs(songs) do
    table.sort(locsz, function(a,b)
        if a.space == b.space then return locations[a.lix].start < locations[b.lix].start end
        return a.space < b.space
    end)
    for _,locinfo in ipairs(locsz) do
        if locinfo.space >= song.size then
            locinfo.space = locinfo.space - song.size
            local loc = location(locations[locinfo.lix])
            local n = song.filename
            song_ids[n] = locinfo.lix-2 << 4 | #loc.songs_lo.instructions-1
            local s = function(str) return section(str..n) end
            s("tt_InsCtrlTable") byte(song.insctrltable)
            s("tt_InsADIndexes") byte(song.insadindexes)
            s("tt_InsSustainIndexes") byte(song.inssustainindexes)
            s("tt_InsReleaseIndexes") byte(song.insreleaseindexes)
            s("tt_InsFreqVolTable") byte(song.insfreqvoltable)
            s("tt_PercIndexes") byte(song.percindexes)
            s("tt_PercFreqTable") byte(song.percfreqtable)
            s("tt_PercCtrlVolTable") byte(song.percctrlvoltable)
            local patterns = {}
            for i,pattern in ipairs(song.patterns) do
                table.insert(patterns, section("pattern"..n..i)) byte(pattern)
            end
            s("tt_PatternSpeeds") byte(song.patternspeeds)
            s("tt_PatternPtrLo") byte_lo(patterns)
            s("tt_PatternPtrHi") byte_hi(patterns)
            s("tt_SequenceTable") byte(song.sequence[1]) byte(song.sequence[2])
            s("tt_song")
                local function ptr(t, v) t=t..n v=v or 0 byte_lo(\(symbols[t]-v)) byte_hi(\(symbols[t]-v)) end
                ptr("tt_InsCtrlTable", 1)
                ptr("tt_InsADIndexes", 1) 
                ptr("tt_InsSustainIndexes", 1) 
                ptr("tt_InsReleaseIndexes", 1) 
                ptr("tt_InsFreqVolTable") 
                ptr("tt_PercIndexes", 17) 
                ptr("tt_PercFreqTable", 1) 
                ptr("tt_PercCtrlVolTable", 1) 
                ptr("tt_PatternSpeeds") 
                ptr("tt_SequenceTable") 
                ptr("tt_PatternPtrLo") 
                ptr("tt_PatternPtrHi") 
                dc.b song.globalspeed and 1 or 0, song.speed-1, song.oddspeed-1, song.usefunktempo and 1 or 0
                dc.b song.c0init, song.c1init
            -- append song pointer to pointer table
            section(loc.songs_lo) byte_lo("tt_song"..n)
            section(loc.songs_hi) byte_hi("tt_song"..n)
            -- rom0 data
            section(locinfo.secmeta)
                byte(meta(song.author))
                byte(meta(song.name and #song.name>0 and song.name or song.filename))
            break
        end
    end
end

----------------------------------------------------------------------
-- songs data
----------------------------------------------------------------------

-- sort songs by alphabetic order
local song_ixs = {}
for k in pairs(song_ids) do song_ixs[#song_ixs+1] = k end
table.sort(song_ixs)
for k,v in ipairs(song_ixs) do song_ixs[k] = song_ids[v] end
location(rom0)
@@song_table byte(song_ixs)

-- player pointers table
local song_players = {}
for i=1,7 do
    table.insert(song_players, \(op_resolve(far_stubs[location(_ENV['rom'..i]).tt_tick][rom0])-1))
end
location(rom0)
@@song_players_lo byte_lo(song_players)
@@song_players_hi byte_hi(song_players)

@@song_tick
    lda cur_song_ix
    tax lsr lsr lsr lsr tay
    lda song_players_hi,y pha lda song_players_lo,y pha
    txa dna #0xf tay
    rts

@@song_switch
    ldy tt_song_ix_next sty tt_song_ix lda song_table,y sta cur_song_ix
    lda #0x80 sta tt_timer -- request song reset from player
    lda #0 ldx #8 @_resettt sta tt_timer,x dex bne _resettt
    ldx #5 @_resetaud sta AUDC0s,x dex bpl _resetaud
    rts

local song_norm = function()
    -- clamp to valid TIA range
    lda AUDC0s dna #0x0f sta AUDC0s lda AUDC1s dna #0x0f sta AUDC1s
    lda AUDF0s dna #0x1f sta AUDF0s lda AUDF1s dna #0x1f sta AUDF1s
    lda AUDV0s dna #0x0f sta AUDV0s lda AUDV1s dna #0x0f sta AUDV1s
end

@volmul for x=0,255 do dc.b math.floor(15*(((x/16)/16)*((x%16)/15))) end

local song_transition = function()
    lda song_delay beq _transdone bpl _transapply
    inc song_delay bne _noswitch
    jsr song_switch jmp _transdone
@_noswitch
    lda song_delay eor #0xff sec adc #0
@_transapply
    asl asl asl dna #0xf0 ora AUDV0s tay ldx volmul,y stx AUDV0s
    dna #0xf0 ora AUDV1s tay ldx volmul,y stx AUDV1s
@_transdone
    -- set result
    ldx #5 @_setaud lda AUDC0s,x sta AUDC0,x dex bpl _setaud
end

----------------------------------------------------------------------
-- display song name and author
----------------------------------------------------------------------

section{ "font", align=256 } dc.b
    0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,-- <SPC>
    0x18,0x3c,0x66,0x7e,0x66,0x66,0x66,0x00,-- A
    0x7c,0x66,0x66,0x7c,0x66,0x66,0x7c,0x00,-- B
    0x3c,0x66,0x60,0x60,0x60,0x66,0x3c,0x00,-- C
    0x78,0x6c,0x66,0x66,0x66,0x6c,0x78,0x00,-- D
    0x7e,0x60,0x60,0x78,0x60,0x60,0x7e,0x00,-- E
    0x7e,0x60,0x60,0x78,0x60,0x60,0x60,0x00,-- F
    0x3c,0x66,0x60,0x6e,0x66,0x66,0x3c,0x00,-- G
    0x66,0x66,0x66,0x7e,0x66,0x66,0x66,0x00,-- H
    0x3c,0x18,0x18,0x18,0x18,0x18,0x3c,0x00,-- I
    0x1e,0x0c,0x0c,0x0c,0x0c,0x6c,0x38,0x00,-- J
    0x66,0x6c,0x78,0x70,0x78,0x6c,0x66,0x00,-- K
    0x60,0x60,0x60,0x60,0x60,0x60,0x7e,0x00,-- L
    0x63,0x77,0x7f,0x6b,0x63,0x63,0x63,0x00,-- M
    0x66,0x76,0x7e,0x7e,0x6e,0x66,0x66,0x00,-- N
    0x3c,0x66,0x66,0x66,0x66,0x66,0x3c,0x00,-- O
    0x7c,0x66,0x66,0x7c,0x60,0x60,0x60,0x00,-- P
    0x3c,0x66,0x66,0x66,0x66,0x3c,0x0e,0x00,-- Q
    0x7c,0x66,0x66,0x7c,0x78,0x6c,0x66,0x00,-- R
    0x3c,0x66,0x60,0x3c,0x06,0x66,0x3c,0x00,-- S
    0x7e,0x18,0x18,0x18,0x18,0x18,0x18,0x00,-- T
    0x66,0x66,0x66,0x66,0x66,0x66,0x3c,0x00,-- U
    0x66,0x66,0x66,0x66,0x66,0x3c,0x18,0x00,-- V
    0x63,0x63,0x63,0x6b,0x7f,0x77,0x63,0x00,-- W
    0x66,0x66,0x3c,0x18,0x3c,0x66,0x66,0x00,-- X
    0x66,0x66,0x66,0x3c,0x18,0x18,0x18,0x00,-- Y
    0x7e,0x06,0x0c,0x18,0x30,0x60,0x7e,0x00 -- Z

-- a = line count
@@print12
    sta print_line_count
    lda#6 sta NUSIZ0 sta NUSIZ1
    -- set MSB of font character addresses
    lda#font>>8 ldx#23 @_loadfont sta print_ptr,x dex dex bpl _loadfont
    -- position sprites
    samepage
        sta WSYNC
        ldx#6 @_delay dex bne _delay
        sta RESP0 nop sta RESP1 lda#0x70 sta HMP0 lda#0x60 sta HMP1 sta WSYNC sta HMOVE
    end
    @_loop
        -- load text line
        ldx#0 ldy#0 @_loadline lda (print_txt),y sta print_ptr,x inx inx iny cpy#12 bne _loadline
        lda#0x80 sta HMP0 sta HMP1
        ldy#0 samepage @_printline
            sta WSYNC sta HMOVE
            -- first scanline
            lda (print_ptr+2),y sta GRP0 lda (print_ptr+6),y sta GRP1
            lda (print_ptr+22),y tax sleep(6)
            lda (print_ptr+10),y sta GRP0 lda (print_ptr+14),y sta GRP1 lda (print_ptr+18),y sta GRP0 stx GRP1
            sta HMCLR sleep(8) sta HMOVE
            -- second scanline
            lda (print_ptr),y sta GRP0 lda (print_ptr+4),y sta GRP1
            lda (print_ptr+20),y tax lda#0x80 sta HMP0 sta HMP1 nop
            lda (print_ptr+8),y sta GRP0 lda (print_ptr+12),y sta GRP1 lda (print_ptr+16),y sta GRP0 stx GRP1
            iny cpy#8 bne _printline
        end
        dec print_line_count beq _end
        lda print_txt clc adc#12 sta print_txt lda print_txt+1 adc#0 sta print_txt+1
    jmp _loop
@_end
    lda#0 sta GRP0 sta GRP1
    rts

----------------------------------------------------------------------
-- equalizer anim
----------------------------------------------------------------------

-- convert to freq: http://atariage.com/forums/topic/257526-musicsound-programming-question-atari-2600/
-- maps AUDCi to 0-7 3 bits (<<5) value for wave length of: 1, 2, 6, 15, 31, 93, 465, 511
@@wavlen samepage
dc.b 0x00,0x60,0xC0,0xC0,0x20,0x20,0x80,0x80,
     0xF0,0x80,0x80,0x00,0x40,0x40,0xA0,0xA0
end
local wavelen_map = { 1, 2, 6, 15, 31, 93, 465, 511 }
local freq_ranges = { 30, 60, 120, 240, 480, 960, 1920, 9999999 }
local t = {}
for i=0,255 do
    local wavelen = wavelen_map[(i>>5)+1]
    local note = (i&31)+1
    local freq = 3546894 / 114 / wavelen / note
    for x=1,9 do
        if freq <= freq_ranges[x] then
            t[#t+1] = x-1
            break
        end
    end
end
section{'regfreq', align=256} byte(t)
@@vm_pf2 samepage
dc.b 0x00,0x80,0xC0,0xE0,0xF0,0xF8,0xFC,0xFE,
     0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF
end
@@vm_pf1 samepage
dc.b 0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,
     0x00,0x01,0x03,0x07,0x0F,0x1F,0x3F,0x7F
end
@@vm_col samepage
dc.b 0x3C,0x7C,0x9C,0xDC,0x2C,0x4C,0x6C,0xAC
end
local vumeter_tick = function()
    lda #0 ldy #15 @_vudec ldx vubars,y dex bmi _vudecskip stx vubars,y @_vudecskip dey bpl _vudec
    lda AUDF0s ldy AUDC0s ora wavlen,y tax ldy regfreq,x
    lda AUDV0s cmp vubars,y bcc _vuless0 sta vubars,y @_vuless0
    lda AUDF1s ldy AUDC1s ora wavlen,y tax ldy regfreq,x
    lda AUDV1s cmp vubars+8,y bcc _vuless1 sta vubars+8,y @_vuless1
end
local vumeter_draw = function()
    lda #ctrlpf.PF_MIRRORED sta CTRLPF
    ldy #7
@_vudraw
    samepage
        lda #16 sta tmp
@_vudraw1
        sta WSYNC
        lda vm_col,y sta COLUPF sleep(4)
        ldx vubars,y
        lda vm_pf1,x sta PF1
        lda vm_pf2,x sta PF2
        sleep(8)
        ldx vubars+8,y
        lda vm_pf2,x sta PF2
        lda vm_pf1,x sta PF1
        dec tmp bpl _vudraw1
        sta WSYNC lda #0 sta PF2 sta PF1
        sta WSYNC
        dey bpl _vudraw
    end
    lda #0 sta CTRLPF
    sta WSYNC sta WSYNC
end

@@song_count dc.b #songs

local next_song = function()
    inc tt_song_ix_next lda song_count cmp tt_song_ix_next bne _nextsongdone lda#0 sta tt_song_ix_next @_nextsongdone
end

local prev_song = function()
    dec tt_song_ix_next bpl _prevsongdone lda song_count sta tt_song_ix_next dec tt_song_ix_next @_prevsongdone
end

local check_input = function()
    local JOYSTICK_RIGHT= 0x80
    local JOYSTICK_LEFT = 0x40
    lda SWCHA cmp input_prev beq _inputend
    sta input_prev
    lda #JOYSTICK_RIGHT bit input_prev bne _noright next_song() jmp _inputdone @_noright
    lda #JOYSTICK_LEFT  bit input_prev bne _inputdone prev_song()
@_inputdone
    lda #0xe0 sta song_delay
@_inputend
end

local tick = function()
    jsr song_tick
    song_norm()
    song_transition()
    vumeter_tick()
end

@@mul24 for x=0,9 do byte(x*24) end

local kernel = function()
    lda#0x8a sta COLUP0 sta COLUP1
    lda cur_song_ix tax lsr lsr lsr lsr tay
    lda songs_meta_lo,y sta print_txt lda songs_meta_hi,y sta print_txt+1
    txa dna #0xf tay lda mul24,y clc adc print_txt sta print_txt lda print_txt+1 adc #0 sta print_txt+1
    lda#1 jsr print12

    vumeter_draw()

    lda#0xaa sta COLUP0 sta COLUP1
    lda print_txt clc adc #12 sta print_txt lda print_txt+1 adc #0 sta print_txt+1
    lda#1 jsr print12
end

@@main
    init()
    lda SWCHA sta input_prev
    jsr song_switch
@_frame
    overscan(check_input) vblank(tick) screen(kernel) jmp _frame

; -- needed if last instruction is implied
writebin(filename..'.bin')
writesym(filename..'.sym')
print(stats)