uxn11/mp3.tal

( mp3.tal )

( commands are ended by newlines: )
( )
( help                         show all these commands )
( load FILE                    load FILE and start playing )
( loadpaused FILE              load FILE without playing )
( pause                        pause, or unpause, playback )
( stop                         stops playback, unloads file )
( seek #                       seeks to sample # )
( seek +N | seek -N            seeks forward, or back, N samples )
( seek +Ns | seek -Ns          seeks forward, or back, N seconds )
( jump #                       jumps to MPEG frame # )
( jump +N | jump -N            jumps forward, or back, N frames )
( jump +Ns | jump -Ns          jumps forward, or back, N seconds )
( volume P                     set volume to P percent, 0-100 )
( mute                         mute playback )
( unmute                       unmute playback )
( tag                          print all ID3 data; seeking back may remove tag data )

@Console [
  |10 &vector $2
  |12 &read $1
  ( 13 - 14 padding )
  |15 &live $1
  |15 &exit $1
  |17 &type $1
  |18 &write $1
  |19 &error $1
  ( 1a - 1b padding )
  |1c &addr $2
  |1e &mode $1
  |1f &exec $1
]

|0100
    ( initialize buffer )
    ;buffer ;buffer/pos STA2

    ( run mpg123 )
    ;on-console .Console/vector DEO2
    ;program .Console/addr DEO2 ( cmd addr )
    #03 .Console/mode DEO ( cmd mode )
    #01 .Console/exec DEO ( exec )

    ;cmd1 print
    ;cmd2 print

    BRK

@printerr ( s* -> )
    LDAk ?{ #0a .Console/error DEO POP2 JMP2r }
    LDAk .Console/error DEO INC2 !printerr

@print ( s* -> )
    LDAk ?{ POP2 JMP2r }
    LDAk .Console/write DEO INC2 !print

@on-console ( -> brk )
    .Console/type DEI #01 EQU ?{ BRK }  ( )
    .Console/read DEI #0a EQU ?&newline ( )
    ;buffer/pos LDA2k STH2k             ( pos* buf* [buf*] )
    .Console/read DEI STH2r STA         ( pos* buf ; buf<-c )
    INC2 SWP2 STA2 BRK                  ( ; pos<-buf+1 )
    &newline                            ( )
    #00 ;buffer/pos LDA2 STA on-line    ( ; buf<-0, run on-line )
    ;buffer ;buffer/pos STA2 BRK        ( )


( called when a newline is reached )
( buffer is guaranteed to be null-terminated )
( newline is implied but not included )
@on-line ( -> )
    ;buffer LDAk LIT "@ EQU ?{ POP2 JMP2r }
    INC2k LDA LIT "F EQU ?on-frame
    ( INC2k LDA LIT "H EQU ?on-help )
    ( INC2k LDA LIT "I EQU ?on-id3 )
    ( INC2k LDA LIT "P EQU ?on-paused )
    ( INC2k LDA LIT "R EQU ?on-revision )
    ( INC2k LDA LIT "S EQU ?on-status )
    ( INC2k LDA LIT "T EQU ?on-tag )
    !printerr

( === START NEW CODE === )

( e.g. "@F 184 8713 4.81 227.60" )
( seen when playing )
( the fields here are: )
( @F <curr-frame> <total-frames> <curr-secs> <remaining-secs> )
( )
( debugging output on stderr is: <curr-time> <rem-time> <width> )
@on-frame ( buf0* -> )
    #0003 ADD2                  ( buf1* ; skip "@F " )
    #20 find-next INC2          ( buf2* ; skip curr frame )
    #20 find-next INC2          ( buf3* ; skip next frame )
    parse-dec STH2 INC2         ( buf4* [curr*] ; parse curr time )
    LDAk LIT "5 LTH ?{ INC2r }  ( buf4* [curr*] ; maybe round curr )
    #20 find-next INC2          ( buf5* [curr*] ; skip fractional part )
    parse-dec STH2 INC2         ( buf4* [curr* rem*] ; parse total time )
    LDAk LIT "5 LTH ?{ INC2r }  ( buf4* [curr* rem*] ; maybe round rem )
    POP2 STH2r STH2r SWP2       ( curr* rem* )
    OVR2 emit #2019 DEO         ( curr* rem* ; print curr )
    DUP2 emit #2019 DEO         ( curr* rem* ; print rem )
    OVR2 ADD2 SWP2              ( total* curr* )
    calc-width emit #0a19 DEO   ( width* )
    JMP2r                       ( width* )

( emit a short in hexadecimal notation. )
@emit ( n* -> )
    SWP /byte
    &byte DUP #04 SFT /hex #0f AND ( >> )
    &hex #30 ADD DUP #39 GTH #27 MUL ADD .Console/error DEO JMP2r

( returns value between 0000 and 00d0 )
( )
( the basic idea is that we shift both values left until )
( the total is small enough that it can be multiplied by )
( 0xd0, i.e. 208. we take some care to round correctly, )
( which helps give a smoother transition between values. )
@calc-width ( total* curr* -> width* )
    STH2    ( total* [curr*] )
    DUP2 #013c LTH2 ?&ready
    &scale DUP2 #0277 LTH2 ?&almost #01 SFT2 LITr 01 SFT2r !&scale
    &almost INC2 #01 SFT2 INC2r LITr 01 SFT2r
    &ready LIT2r 00d0 MUL2r STH2r SWP2 DIV2 JMP2r

( find the next occurrence of a byte in the given string. )
( )
( returns the position of the character found. )
@find-next ( buf* c^ -> buf+i* )
    STH &loop LDAk STHkr EQU ?{ INC2 !&loop } POPr JMP2r

( parse a decimal number as a short )
( )
( returns an updated buffer position and the parsed short )
@parse-dec ( buf* -> buf+i* x* )
    LIT2r 000a LIT2r 0000       ( buf* [10* acc*] )
    &loop LDAk LIT "0 SUB       ( buf+i* n^ [10* acc*] )
    DUP #09 GTH ?&done          ( buf+i* n^ [10* acc*] )
    OVR2r MUL2r #00 SWP         ( buf+i* n* [10* 10acc*] )
    STH2 ADD2r INC2 !&loop      ( buf+i+1* [10* 10acc+n*] )
    &done POP STH2r POP2r JMP2r ( buf+i* acc* )

( === END NEW CODE === )

( e.g. "@H HELP/H: command listing (LONG/SHORT forms), command case insensitve" )
( seen in response to the "help" command )
@on-help ( buf* -> )
    POP2r JMP2r

( e.g. "@I ID3v2.artist:Chipzel" )
( seen when loading a track )
@on-id3 ( buf* -> )
    POP2 JMP2r

( e.g. "@P 0" or "@P 1" )
( seen when pausing or unpausing )
@on-paused ( buf* -> )
    POP2 JMP2r

( e.g. "@R MPG123 (ThOr) v10" )
( seen on start up )
@on-revision ( buf* -> )
    POP2 JMP2r

( e.g. "@S 1.0 3 44100 Joint-Stereo 0 1044 2 0 0 0 320 0 1" )
( seen when playback starts )
@on-status ( buf* -> )
    POP2 JMP2r

( e.g. "@T ID3v2.TPE1:" )
( seen in response to the "tag" command for extended tag info )
@on-tag ( buf* -> )
    POP2 JMP2r

@program
    "mpg123 20 "-R 00

@cmd1
    "loadpaused 20 "tokyo-skies.mp3 0a 00

@cmd2
    "pause 0a 00


@buffer $200 &pos $2 ( input buffer )