mirror of
https://github.com/irmen/prog8.git
synced 2024-11-03 13:07:54 +00:00
259 lines
8.0 KiB
Lua
259 lines
8.0 KiB
Lua
%import textio
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%import diskio
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%import cx16diskio
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%import floats
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%import adpcm
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%import wavfile
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%option no_sysinit
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;
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; This program can stream a regular .wav file from the sdcard.
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; It can be uncompressed or IMA-adpcm compressed (factor 4 lossy compression).
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; See the "adpcm" module source for tips how to create those files.
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;
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; Note that 8 bit wav files are *unsigned* values whereas Vera wants *signed* values
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; so these have to be converted on the fly. 16 bit wav files are signed already.
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;
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; The playback is done via AFLOW irq handler that fills the audio fifo buffer
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; with around 1 Kb of new audio data. (copies raw pcm data or decodes adpcm block)
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; In the meantime the main program loop reads new data blocks from the wav file
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; as it is being played.
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;
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; NOTE: stripping the wav header and just having the raw pcm data in the file
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; is slightly more efficient because the data blocks are then sector-aligned on the disk
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;
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main {
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uword vera_rate_hz
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ubyte vera_rate
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sub start() {
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uword buffer = memory("buffer", 1024, 256)
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str MUSIC_FILENAME = "?"*32
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txt.print("name of .wav file to play: ")
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while 0==txt.input_chars(MUSIC_FILENAME) {
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; until user types a name...
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}
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bool wav_ok = false
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txt.print("\nchecking ")
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txt.print(MUSIC_FILENAME)
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txt.nl()
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if diskio.f_open(8, MUSIC_FILENAME) {
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void cx16diskio.f_read(buffer, 128)
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wav_ok = wavfile.parse_header(buffer)
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diskio.f_close()
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}
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if not wav_ok {
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error("no good wav file!")
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}
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calculate_vera_rate()
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txt.print("wav format: ")
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txt.print_ub(wavfile.wavefmt)
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txt.print("\nchannels: ")
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txt.print_ub(wavfile.nchannels)
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txt.print("\nsample rate: ")
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txt.print_uw(wavfile.sample_rate)
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txt.print("\nbits per sample: ")
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txt.print_uw(wavfile.bits_per_sample)
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txt.print("\ndata size: ")
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txt.print_uwhex(wavfile.data_size_hi, true)
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txt.print_uwhex(wavfile.data_size_lo, false)
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txt.print("\nvera rate: ")
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txt.print_ub(vera_rate)
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txt.print(" = ")
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txt.print_uw(vera_rate_hz)
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txt.print(" hz\n")
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if wavfile.wavefmt==wavfile.WAVE_FORMAT_DVI_ADPCM {
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txt.print("adpcm block size: ")
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txt.print_uw(wavfile.block_align)
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txt.nl()
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}
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if wavfile.nchannels>2 or
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(wavfile.wavefmt!=wavfile.WAVE_FORMAT_DVI_ADPCM and wavfile.wavefmt!=wavfile.WAVE_FORMAT_PCM) or
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wavfile.sample_rate > 48828 or
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wavfile.bits_per_sample>16 {
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error("unsupported format!")
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}
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if wavfile.wavefmt==wavfile.WAVE_FORMAT_DVI_ADPCM {
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if(wavfile.block_align!=256 or wavfile.nchannels!=1) {
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error("unsupported format!")
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}
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}
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txt.print("\ngood file! playback starts!\n")
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cx16.rombank(0) ; activate kernal bank for faster calls
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cx16.VERA_AUDIO_RATE = 0 ; halt playback
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cx16.VERA_AUDIO_CTRL = %10101111 ; mono 16 bit
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if wavfile.nchannels==2
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cx16.VERA_AUDIO_CTRL = %10111111 ; stereo 16 bit
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if(wavfile.bits_per_sample==8)
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cx16.VERA_AUDIO_CTRL &= %11011111 ; set to 8 bit instead
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repeat 1024
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cx16.VERA_AUDIO_DATA = 0 ; fill buffer with short silence
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sys.set_irqd()
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cx16.CINV = &interrupt.handler
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cx16.VERA_IEN = %00001000 ; enable AFLOW only for now
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sys.clear_irqd()
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if diskio.f_open(8, MUSIC_FILENAME) {
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uword block_size = 1024
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if wavfile.wavefmt==wavfile.WAVE_FORMAT_DVI_ADPCM
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block_size = wavfile.block_align
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void cx16diskio.f_read(buffer, wavfile.data_offset) ; skip to actual sample data start
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void cx16diskio.f_read(buffer, block_size) ; preload buffer
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cx16.VERA_AUDIO_RATE = vera_rate ; start playback
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repeat {
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interrupt.wait_and_clear_aflow_semaphore()
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;; cx16.vpoke(1,$fa00, $a0) ; paint a screen color
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uword size = cx16diskio.f_read(buffer, block_size)
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;; cx16.vpoke(1,$fa00, $00) ; paint a screen color
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if size<block_size
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break
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txt.chrout('.')
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}
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diskio.f_close()
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} else {
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txt.print("load error")
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}
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cx16.VERA_AUDIO_RATE = 0 ; halt playback
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txt.print("done!\n")
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repeat {
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}
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}
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sub calculate_vera_rate() {
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const float vera_freq_factor = 25e6 / 65536.0
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vera_rate = (wavfile.sample_rate as float / vera_freq_factor) + 1.0 as ubyte
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vera_rate_hz = (vera_rate as float) * vera_freq_factor as uword
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}
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sub error(str msg) {
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txt.print(msg)
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repeat {
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}
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}
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}
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interrupt {
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bool aflow_semaphore
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asmsub wait_and_clear_aflow_semaphore() {
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%asm {{
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- wai
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lda aflow_semaphore
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bne -
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inc aflow_semaphore
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rts
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}}
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}
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sub handler() {
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if cx16.VERA_ISR & %00001000 {
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; AFLOW irq occurred, refill buffer
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aflow_semaphore = 0
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if wavfile.wavefmt==wavfile.WAVE_FORMAT_DVI_ADPCM
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adpcm_block()
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else if wavfile.bits_per_sample==16
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uncompressed_block_16()
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else
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uncompressed_block_8()
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} else if cx16.VERA_ISR & %00000001 {
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cx16.VERA_ISR = %00000001
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; TODO handle vsync irq
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}
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%asm {{
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ply
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plx
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pla
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rti
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}}
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}
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asmsub uncompressed_block_8() {
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; optimized loop to put 1024 bytes of data into the fifo as fast as possible
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; converting unsigned wav 8 bit samples to signed 8 bit on the fly
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%asm {{
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lda main.start.buffer
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sta cx16.r0L
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lda main.start.buffer+1
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sta cx16.r0H
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ldx #4
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- ldy #0
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- lda (cx16.r0),y
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sec
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sbc #128 ; convert to signed
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sta cx16.VERA_AUDIO_DATA
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iny
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bne -
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inc cx16.r0H
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dex
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bne --
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rts
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}}
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; original prog8 code:
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; uword @requirezp ptr = main.start.buffer
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; ubyte @requirezp sample
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; repeat 1024 {
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; sample = @(ptr) - 128
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; cx16.VERA_AUDIO_DATA = sample
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; ptr++
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; }
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}
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asmsub uncompressed_block_16() {
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; optimized loop to put 1024 bytes of data into the fifo as fast as possible
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%asm {{
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lda main.start.buffer
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sta cx16.r0L
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lda main.start.buffer+1
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sta cx16.r0H
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ldx #4
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- ldy #0
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- lda (cx16.r0),y
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sta cx16.VERA_AUDIO_DATA
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iny
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bne -
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inc cx16.r0H
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dex
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bne --
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rts
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}}
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; original prog8 code:
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; uword @requirezp ptr = main.start.buffer
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; repeat 1024 {
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; cx16.VERA_AUDIO_DATA = @(ptr)
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; ptr++
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; }
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}
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sub adpcm_block() {
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; refill the fifo buffer with one decoded adpcm block (1010 bytes of pcm data)
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uword @requirezp nibblesptr = main.start.buffer
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adpcm.init(peekw(nibblesptr), @(nibblesptr+2))
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cx16.VERA_AUDIO_DATA = lsb(adpcm.predict)
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cx16.VERA_AUDIO_DATA = msb(adpcm.predict)
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nibblesptr += 4
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repeat 252 {
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ubyte @zp nibble = @(nibblesptr)
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adpcm.decode_nibble(nibble & 15) ; first word
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cx16.VERA_AUDIO_DATA = lsb(adpcm.predict)
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cx16.VERA_AUDIO_DATA = msb(adpcm.predict)
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adpcm.decode_nibble(nibble>>4) ; second word
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cx16.VERA_AUDIO_DATA = lsb(adpcm.predict)
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cx16.VERA_AUDIO_DATA = msb(adpcm.predict)
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nibblesptr++
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}
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}
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}
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