Document MML, fix MML stopping

docs/intro.tex

@@ -54,3 +54,8 @@ \subsection{Fractals}
 
 The fractals can then be shown by typing \texttt{koch weed1 bush1 bush2}. When a fractal have finished drawing, press any key to continue.
 
+\subsection{Music}
+
+The mmldemo package demonstrates the MML music capabilities. To run:
+
+\texttt{s" mmldemo" load frere-jaques sarias-song}

docs/manual.tex

@@ -26,6 +26,7 @@
 \input{editor.tex}
 \input{forth.tex}
 \input{gfx.tex}
+\input{mml.tex}
 \appendix
 \input{asm.tex}
 \input{memmap.tex}

docs/mml.tex

@@ -0,0 +1,25 @@
+\chapter{Music}
+
+\section{Music Macro Language}
+
+Music Macro Language (MML) has been used since the 1970s to sequence music on computer and video game systems. MML support is included in durexForth, starting with version 1.3. The package is loaded with \texttt{s" mml" load"}. Two demonstration songs can be found in the \texttt{mmldemo} package.
+
+MML songs are played using the Forth word \texttt{play-mml} which takes three strings, one MML melody for each of the three SID voices. An example song is as follows:
+
+\begin{verbatim}
+: frere-jaques
+s" o3l4fgaffgafab->c&c<ab->c&cl8cdc<b-l4af>l8cdc<b-l4affcf&ffcf&f"
+s" r1o3l4fgaffgafab->c&c<ab->c&cl8cdc<b-l4af>l8cdc<b-l4affcf&ffcf&f"
+s" " play-mml ;
+\end{verbatim}
+
+\section{Commands}
+
+\begin{description}
+\item[cdefgab] The letters \texttt{c} to \texttt{b} represent musical notes. Sharp notes are produced by appending a \texttt{+}, flat notes are produced by appending a \texttt{-}. The length of a note is specified by appending a number representing its length as a fraction of a whole note -- for example, \texttt{c8} represents a C eight note, and \texttt{f+2} an F\# half note. Appending a \texttt{.} increases the duration of the note by half of its value.
+\item[o] Followed by a number, \texttt{o} selects the octave the instrument will play in.
+\item[r] A rest. The length of the rest is specified in the same manner as the length of a note.
+\item[$<$,$>$] Used to step down or up one octave.
+\item[l] Followed by a number, specifies the default length used by notes or rests which do not explicitly specify one.
+\item[\&] Ties two notes together.
+\end{description}

forth_src/mml.fs

@@ -272,11 +272,23 @@ default-pause lda, default-pause 3 + sta,
 :- sid lda,y d400 sta,y
 dey, -branch bpl, ;asm
 
+:asm notdone
+dex, dex,
+0 lda,# voice sta,
+.strget jsr, 0 ora,# +branch bne,
+voice inc,
+.strget jsr, 0 ora,# +branch bne,
+voice inc,
+.strget jsr, 0 ora,# +branch bne,
+0 lda,# 0 sta,x 1 sta,x ;asm
+:+ :+ :+
+0 sta,x ;asm
+
 : play 
 voice0 do-commands
 voice1 do-commands
 voice2 do-commands voicedone 
-a2 c@ wait begin strget while
+a2 c@ wait begin notdone while
 voice0 voicetick
 voice1 voicetick
 voice2 voicetick voicedone 

forth_src/mmldemo.fs

@@ -1,8 +1,11 @@
 
 
 s" mml" load
-: mmldemo
-# saria's song (zelda lost woods theme)
+: frere-jaques
+s" o3l4fgaffgafab->c&c<ab->c&cl8cdc<b-l4af>l8cdc<b-l4affcf&ffcf&f"
+s" r1o3l4fgaffgafab->c&c<ab->c&cl8cdc<b-l4af>l8cdc<b-l4affcf&ffcf&f"
+s" " play-mml ;
+: sarias-song
 s" l16o3f8o4crcrcro3f8o4crcrcro3f8o4crcrcro3f8o4crcro3cre8o4crcrcro3e8o4crcrcro3e8o4crcrcro3e8o4crcro3c8f8o4crcrcro3f8o4crcrcro3f8o4crcrcro3f8o4crcro3cro3e8o4crcrcro3e8o4crcrcro3e8o4crcrcro3e8o4crcrc8o3drardraro2gro3gro2gro3grcro4cro3cro4cro2aro3aro2aro3aro3drardraro2gro3gro2gro3grcro4cro3cro4cro2aro3aro2aro3aro3drardraro2gro3gro2gro3grcro4cro3cro4cro2aro3aro2aro3aro3drararrrdrararrrcrbrbrrrcrbrbrrrerarrrarerarrrarerg+rg+rg+rg+rrre&er"
 s" l16o5frarb4frarb4frarbr>erd4<b8>cr<brgre2&e8drergre2&e4frarb4frarb4frarbr>erd4<b8>crer<brg2&g8brgrdre2&e4r1r1frgra4br>crd4e8frg2&g4r1r1<f8era8grb8ar>c8<br>d8cre8drf8er<b>cr<ab1&b2r4e&e&er"
 s" l16r1r1r1r1r1r1r1r1o4drerf4grarb4>c8<bre2&e4drerf4grarb4>c8dre2&e4<drerf4grarb4>c8<bre2&e4d8crf8erg8fra8grb8ar>c8<br>d8crefrde1&e2r4"