From 6c2ef8d2ddd3f9c148e3da928bd1bebbca1a654a Mon Sep 17 00:00:00 2001
From: tildearrow <me@tildearrow.org>
Date: Mon, 21 Apr 2025 19:38:19 -0500
Subject: [PATCH] 6502 command stream player, part 16

incomplete vibrato/pitch implementation
incomplete porta implementation
prepare for arp impl
---
 src/asm/6502/nes/test.s |   7 +-
 src/asm/6502/seq.bin    | Bin 3935 -> 3943 bytes
 src/asm/6502/stream.s   | 196 ++++++++++++++++++++++++++++++++++------
 3 files changed, 173 insertions(+), 30 deletions(-)

diff --git a/src/asm/6502/nes/test.s b/src/asm/6502/nes/test.s
index 81613e06c..077aef5cb 100644
--- a/src/asm/6502/nes/test.s
+++ b/src/asm/6502/nes/test.s
@@ -45,9 +45,9 @@ initPPU:
   bpl -
 startPlayer:
   ; draw some text
-  lda #$21
+  lda #$20
   sta PPUADDR
-  lda #$02
+  lda #$42
   sta PPUADDR
 
   ldx #$00
@@ -123,7 +123,6 @@ irq:
 
 ; command stream player definition
 FCS_MAX_CHAN=8
-FCS_MAX_STACK=10
 
 fcsAddrBase=$30
 fcsZeroPage=$0e
@@ -139,7 +138,7 @@ fcsCmdTableHigh=fcsCmdTableExample
 
 ; data
 helloWorld:
-  .db "Hello, World!"
+  .db "Furnace Test Player"
   .db 0
 
 ppuPalette:
diff --git a/src/asm/6502/seq.bin b/src/asm/6502/seq.bin
index 5b0afe69e9d5a323f32733b683b0f623650903bd..76eda5e4406413bfd03dec3e18819d77e4fe5bbe 100644
GIT binary patch
literal 3943
zcmY*cdyG_P6(1Iu*L{p`D{HX8N@>-i6|}8sNXj-KB$P+VT9&dbEYAh^(OGtfVTOfa
z3yT!ofKnU(z-Z#*52GeFWizb?sF7a0iD0TZIcLM@`iLgtANS6^g_W|5zjJ3XI{Dr6
z-TOVyIp2BBsuiuVWGoh&9XDn+nA=mUlTC|0-}v;S%hC70zn0jOGsb7U({O%f>#WAv
zBeT=-`0R$6GiR3@ozji_HJ+E?BPr4^yq4$kD%<0^8D5{_kwhIB<aU!6WC+9S(&f2M
z=Z)I2{)t#f{r?5~_Ki!m9*+QQ{9LW8%3q9Q<tlq3#;+y2_}NUC4%Lb7kKwda>ePKY
z0ZiJ1NqczG!a0M6PTq@-9lR*cI}Du6OO-EjT6mk~lzOy(bw;N*@`Q;&k9#bS%IU6<
zx<b5HAxM?RTcD1z?G#noKgan{+9_(Aw-kPSEe`73%vTbMt#Lq4<{c)m!J~G6%%cqv
zK@0Gkajqu#$0^0n6)#q4I}ck`+6wAXE8np<>#TB0@oL&55Wb#h#aQ(LJi@^*>g?ZG
zTRqzD(N2%XpPT_+=c$6P@VoK-9_2jBd(_8lJDup^3q~|ph(@yfhXk)q^5s+?&bXZ7
zCPQ(^9>Bm5PuV$s-^%fO2Bw$L)c2j2<ax<qkB0d9bP?O5;h&^S{6`y2dA{?^sPCTQ
zgbDa=ukV73@*<}Ncg}4of5bn<8<UlleA+<IK7P*b#?yzVKWcq@Q1`@?W}ZyzqJv4E
znK|jvDabdj^38XeuX;C*)`s|A+|Bv!u<suC-J<W7d>wJMpI@>#l^Nk*Cjm_17Q-zn
z!OWA)#x&72ZZzwh&A?wQeERMgykPk#&q@I*P6;b;3|fB6;0+njF(+0fr+E~d@d5*Y
zoC}?1Fvd34e8YENhgQFpoK#Vd)>K5kmG0*TtGp21H5CtYm#TQ<?=(QL1<n`r;@Z+7
z@juMlRQ{yXoUL^0wou=dLS>d)tgPT}1LG%B{HFvzp04b=7J~=qhXLk?___&gM_ja}
z0v+S;Ciw4$dm4g+RS4(1XFd8R|H~$rO60`1(naO&kbT6XV;&Z`U-RA59*y3ka`QRA
zyuihs);G`rUq8=zbk=vj4k>w_HGY2PH2;@srNBKFxWkp_X^<Z>1NU%9LzCD?^#|?N
z#TtMtgPxnK?5s<7sWyn7T&10Ix9Pw=>bpn1m}zl?&2J|j2#F6Tp_T_BRn@Q#I|a4R
z=XDAGfpJuA@Qig5qFt<X5;_libkw8advpR6@0c*%<<SY~{g_@J*l(Q`i^0DuA0=GE
z9Na*F3#e=vtMn^-a|!_zzY>ZMRPRe8mRg`&Cswi1co(Ngdz}O>00(_|?Mm%K^ao>=
zj%fI1^9=06?^-v%*Ff3~&lqo<9UXbIl%VosJRD~?rTBe>n<>7T%7=6?q+CdYAq|9d
zAPSb*kX{L?FQnd(dP3?B>8l~_4{4tUE!rE>o{)Bjv@4{YA?=7l<MxoYh13z!){xpm
z+7i;sA+^C~aOhuCihoA%Q|zY@WMGp1_z2jWh<V%{=feq5kAxS4RSoo)(-Sa#L|NN-
zKo(mVtpgL^PHxnwi0H`O3E^wD?(zRr9QbzvXh-m3)85JFEkI*cp9$c_qb!f5aiJw_
z)+}HQar5CMA|cnX>#`&tG?h+9;cGJ0iy0S;UfyfrO*o!Z45SdTL8Sv+fg4caFQxdF
z1z$nihPdD>E%=BTzFXk6wy>4tDdYvnx+*1+(6EjkWTHz3zhNU`*ai|tmH5+0Ag1u^
zX_y~^;USN@VYaZ%JpUH{H6J6w4`uZ12UK{y!4n43W_@QI1{3~-ljxb40YRJ4RE2M(
z)oI}~u-yD@$X~>U=oS7{5^gUXB!TG5uv9myk|`VEJc|a}?TdnMA74lKEAUPT^)Sv6
zo|OiKGigA0P8twM$?u^#qq*h`UY;-%-?jwHJ&KlZ@@O+g4<;qcAG3>kGe;r$(*}Sn
z0~X4UI!%aZ`-7`74c-PE^nPuCPuNj+4&5@HsrYwB7I6^1atzu?5$XfY<>2~i3{Jft
zvC+V8`gOmS#}2B|XecNAlnH2#6@J`QblW&QTloxStCXu!u}Xz|l)p3fZz?Fk_fVyk
zioz>RKvyCUJDu&qpEDH)Y}xO--I2bszGjp>R0da$vV+DfWPp0y6ippN5z#?`D^&Tj
zdcKwzn=;bjZ})fjyZ!xsx8Lh${Q*Dk7yKc=<R2IK1Z)vhplse~%b~z6R8~@N;PwUX
zD}kF0-2T8l5V!+@3!l$bE<>lnubF`G8zvz9eG?G=js@hA*JTfX#neakg6JdsGZPRV
zGXddCCIG!zP`mIEB-_1~KEgk=fE;QsaAX3q8MQ|{o(@zMa7-yop?WDQDSQBuQ<AMb
zgZL)=Qwu<0pz`4U8hNoraw2d?0{0|>|8yD%+*bqlc;HSC2)}6okrI|;H7^GnYxHG}
zrPrT86?h0y8m5uEKV7{D|Iz}EM@9ytL!J`##r1~t!0H-N?7@>3I7`$*uAD%g!+jwP
z->0ZD5G^bQ@#OIc^;eeBfg0s%RJ==BI4g3Xpd7@86Hw1Vv#3h-XoQ<A*mYL4)KMR3
z0;fmp0u)zJkuTUll+x4=E*TmvdW3&uD_Syw$cU<UQ-*}}I*|$mWhSa$Jqp^h0W~Uc
zbe9fHDmU=+h#MTEQA`j`aPsivboLT{%Ld%DIB&{A=m8h+YjDIQwZNyKMp3gwa1#%4
ziNu9Apo-B+I;Tmyyijm`%cyUXdhSx+ZJj=XfTuQ}mB7sf?!my#2d-Ksa-P7q)V<&$
z>LuzrUsl)A=)R;Q`d*>m>Q77HPhw@k0;1+NOE3}B>Qwj<8zTdPTC|AhAp=oanpI7&
z_XyY$L9{?d%^X42c(ew#xCvW!VS|3OsB!n;6xrp`UTxQ+42G$KlPKxJGNY_(Lo=H)
z>X>SFaItbTY84bdqk>K+qmdSCP-&_y<<+W-N=oR|s8{(ocVsAvKG0F!INEI4?a@92
zc%&wI!6TpzkaZpbF9X8Au(cW;68;tbwt!!3cLX+9o(n@&$V*WaRo6oGj*1^taD64z
zB7!W~EyK7{QNKp|6Ln226MoFjtE|wCdd_it!&yqm2p6#r!ZLstE!oka;Eopk%~p|5
zNmTPr$1>qIRnA5brxQo?sxTfwGW@YZbhB|o_*NOC7cJ|Bkn_a(h!(N+q#_?U&A4*)
z8%QcX<Q62u1sN<wCeswA`Yl$TfKoBsl5t0b!Oti}!-nct7`THtQh5PaR>jd69Txl{
z(*?>g3Uk;WRu+Biup#3f7g#=CqRxUZJ@|9i1KyTqq_SkX;;Q0Q*p{9h?SrsA;>#3n
z6J2UR9;rFOog-QgDF{3IcS7T{)7gO?SHpYjQdHr_(e>j+{TrUE_X^3Qd-kRLNMuc-
Snm*~*O~n(H>siPZ%6|YpxhKg0

literal 3935
zcmY*cdyHIV6`$>6UiUHDSZWa3wFQzYhN=-tFfBr91BEW8Qu<)&((Qw?yTfd^!!X0P
z(`CE0p)6EW;~zd^jG9OY5tL;xrc{%1$)`z?kmEUPM;q~<>K}f0?ro`M>G(T$wnitv
zd%k<W=Q-y)uUUKd##A<yO3hC@bLY6*bL+B;Zn$N^SC*|t-~awrrf%wbuj{or$L6k|
zm!E%Neq%vUKXawc3o~5Kk$&N|aV@X%EiWkW+8iIqbbvwL=<=chVfdbW<JzF_O#9IA
zxl~NU{{^4-&zx)zS^}`~s`j21e?E<stNe2*9?S0GFBbObP>1OL7|sXvKHaAez@%N6
zw2Q5Wa|Ruqyc->l@pWn5;^1Unu6$8&CvWnC`k?l&F6i_H%q|8k@AND+@_S<16XU%F
zL0UAu5^8ApK~1HVG?(&0P1`3u#rgF8IH+$kH!_NEqyasdx41x$rETGqrJjVK1^A^j
z|0Bac&MAJbc(6s=x$3p(5l~AT`CtBKo%M^HqL#M=!f$6bVytx)mT>TcI{UZYBbK&X
z+F@z>rY`V$y(;(=znR`^scflYsmSm8K_7bfgp&+blaUhtA;YV){6?;bGv3H?!BLd_
z5e$s-1;5P3EAvSQ)9YwD`!3A#!t9u(QNBH2!}e(SC;2*)kEXFWxOFl#N4f0)p&1Gd
zxM<uE+=)Bqo?JK)9_4$p%{Bb2gPzCvR(}9b5zlbap7;0bo|w|jHm{3{S^mgBV(BR4
zdr#$C9CV+yXAZVUIZm5$XvRV_9-3Nc>Y<Jp?dJzP?kY_1Z?XWU@Jh$jlwjr&e%F~L
zy2d24j`|Etd-x2^F}z^;B+q046{ms~I0h}h?C`n*=v0tuQP4dJ&UldnK+dH>HyGn|
zE;Qc?%?W6AGJ8oyJ=j(e`Gfp0Uv?Wy(cM<@Fn76%H~rci2(~2nl3rX-J|_OFdyyKS
z4Z2Is0o@krJ5_DYGqvX3-0xs~G{=9+@Zx;4|D6;(KtJY!`B8q`g|-tedUBDD@pm))
z7sosY!NDqo3(bp`zRiF438s=b@dx>ua#!*XSUO~}z<e__&smzBp+@)du(8D8PCFau
zK&YR`Exj0;=OHC8^rnx^o#p>zyB?WCkr``#jrOzSM&_BAMlWF>)gQFm5o-jp?6;=e
z+|iNlWP3k)%FS(5zDWCKs5nDInCbClk6+DP6%rqBWz_N@q^cU$k<LNwi}{`mf8RN%
zHaPAbfoQKc`v{%SSUPBFY=#bl;vExayDS}s-Vf>Jf&KOKQYrX%^OJ;2xCS>6;R2dl
zr<%jc-Zj+-ieCf8N2>SbzOr;DbQ`3aJ{tS_$E3Y)WpDvF=%aT|wLe0CG}Y`)hR=3)
zVIO|eJNu(Kq|I2@bbfwv<k@<L8aHw^&A-bjexKm|9KWBd#Pn25<(T%zG!oOkBv_VW
zdNQVBOhYjZ#xxMq6EW?L>2VEOv^%C<G3|`0Kc*cqJ(h&V?J+$XQ*TU<#I!A@tubwh
z>0#Im4*hdZ@wWu$b9_FBAOn*Orw@R=b1BRHX&%XdS`uCcRyEMSkv|91N0d!FSIIID
zqa9%4tJ$w>R77;-{*3S`U-$TbDgpdE18hU^;(7iKKIQ=$t9H8pUM!XPl{_xAj?KCS
zj3I8iSwuqq5W9Xk%SBhIO~RMW4PnL!XNVv5@FsjEqZr5`VuMOAxB@qz!nfr30}sA}
zwg+(`R9X!YGeT44HNNotEMGugfUK)>k_Zj!7(^zTa`*)w2_x+wVYG<5kw9GG=kqW>
z1jDB-4Zv(+n-x9{|5}U@VW*&HU!}rp9cBk<v$Hb}g9(2o$PAwAf}o4gw1k7aIxTz#
zmRq?9`D@q^y~0bfaC_l@W`X2uuBW<Dm0a)<&P!;Z-C`1ai~Kg?SCzLyC>Q4l&*T8%
zOdb&S^MF7~K8a>rbImwjmO6^#o?yA9Wcembn=x9<N{KzcrZ@8xB>#c~Aj^P-#<E}$
zBHG^QbV`G_0|&j*9^p|x=`N#NW-}GP<CG8w;VXxrjU1sq&|D6#Pp9D2dl4HQ?51B=
z+7;}e8cl}E!Z*8s=2+pyuA<+^;icwsDz&KGqFRfpGgSF->fcmVg74AhMyd&a)dh4V
z@^H|%P54Gv@q{mXLo<-*s}yQRsX%3L<s>_3%t8j}#7)uEF`5t^6u3f*Z_x9##Mn@f
z-f(;PShzFX8xDj+VJRF5D`7Pp4eQ~!z$ajfpaNy{y}mphnQC(l4MnCHnI|Jtip+3i
z_C;nSGVu9w^DXF9c+3TaUvL58@40~RcRZkiye_-=epesa4Wf_m&s;$G6&DbmaslYg
zgW845NVbo9`UwBP1Innqz>y2cX4D?r@bsdpfMZJaV^l9SCDjWcWhJHNt%z^JKlK0<
z1}YEkZvij!NDfD4A~Hu1{AbfZWS))8cw}Y=gkSQ2L<zTHHQxp{?$VdLJiY!5s=%ia
zrC}Q7E3?&$@UJ{zJTWpD9rBc@FRpcD5LUMU#U4CqNw7jK<kVs0Ioub*@D)lb1JS}_
zKb{I6q2cBow69I&Hq|au3C@ZfC@2T9AwxYyx28(9G{FTAc3l!Jb<_t6;I!;lp}4Aw
ze8LBkl%{qt<!H1R6#k*FSXmH6MpV5U3M8c0iBu>kGg1BOQP7?bs8NBV%e3#3asxk4
zxWO?R#RSm=Cy!m4&0fMU`+#{7=Uwm+dccLz;D||Tfj2{qqGpNUCKhpt#6TNR#pESA
zu1UMGRB(NFQ1KECUZ&zjoj!qpr#4@b$dn`VRAefVQOiWm6Zn?87hFWWL|x||bsdfF
zD|(afyY*ZBX$Ac0k6sBZAZl*%1QRi>Lxn%(V`M~7i`Ec5WF#p|ORDJ&mVm7ZL<?lp
z%n9T^OZUMRH(|>?*kBkfYTR8oMfxr6*7kms!7x>Dk|bSNW|DP%Xl6q}9aGH?F4pKq
zt%Aa5QqUO`G}2-XDowSeiduC|NgbUU^_rjNhYFNLALyuK96i45wDdRvJW`Xaw*)*4
z$OD#uEr9SZeXT}Eg@28|E#Md1m0@#@YhkDgc_@jZ>RPDYQSpNcuCI<-M34msWDHj-
z>eonrqOOT$!q@v1l@+>C&l$%zoTZM8@H+NESO)N-B|91v+{vP|zKVQQlA3ommI?Q$
za_$8Q`f$XM3S$Y9;g1!fn~xj9x5}8jXjw0WoF~C2w218_6}b>}<I2@<AgP3qTaXMF
z6|fYUOjDTZx7Pd|l#1b%1v4QGekLIrHdMdDz=wz<&Gopl7LLZ~nBWhYE>Mn9n8W_C
zvKC^8bp<mnuzb8Eoz+kV@#k(3ye%(CbH!}M)xxQ;Ej>Hg2Vr|6l#g+n=u!i+q~-*7
zPG~2jAnfSh360M|UoUoC4e#wp(SjQ%*N+$VZ+NcWD<n_uIh4kAi8YC8`bgL@6)P&&
J?T{;${{Y9GC@BB{

diff --git a/src/asm/6502/stream.s b/src/asm/6502/stream.s
index b96b42c61..679ba4ecc 100644
--- a/src/asm/6502/stream.s
+++ b/src/asm/6502/stream.s
@@ -4,7 +4,6 @@
 ; usage:
 ; define the following constants:
 ; - FCS_MAX_CHAN: the number of channels in your stream
-; - FCS_MAX_STACK: the maximum stack size
 ; - fcsAddrBase: player state address base
 ; - fcsZeroPage: player state address base for zero-page-mandatory variables
 ; - fcsGlobalStack: player stack (best placed in a page)
@@ -26,6 +25,7 @@
 ; calculated from player constants
 fcsDelays=fcsPtr+8
 fcsSpeedDial=fcsPtr+24
+fcsStackSize=fcsPtr+40+(FCS_MAX_CHAN*2)
 
 ; variables
 ; these may be read by your command handling routines
@@ -53,6 +53,8 @@ chanPortaTarget=fcsAddrBase+24+(FCS_MAX_CHAN*8)+1 ; char
 chanVol=fcsAddrBase+24+(FCS_MAX_CHAN*10) ; short
 chanVolSpeed=fcsAddrBase+24+(FCS_MAX_CHAN*12) ; short
 chanPan=fcsAddrBase+24+(FCS_MAX_CHAN*14) ; short
+chanArpStage=fcsAddrBase+24+(FCS_MAX_CHAN*16) ; char
+chanArpTicks=fcsAddrBase+24+(FCS_MAX_CHAN*16)+1 ; char
 
 ; may be used for driver detection
 fcsDriverInfo:
@@ -481,19 +483,38 @@ fcsChannelCmd:
     sta fcsTempPtr+1
     jmp (fcsTempPtr)
 
+; this is called when vibrato depth is zero
+fcsChanPitchShortcut:
+  ; extend pitch sign
+  lda chanPitch,x
+  sta fcsArg0
+  bmi +
+  lda #0
+  sta fcsArg0+1
+  beq ++
++ lda #$ff
+  sta fcsArg0+1
+++
+  ; dispatch command
+  ldy #9
+  jsr fcsDispatchCmd
+  ; end
+  jmp fcsChanDoPorta
+
 ; x: channel*2
 ; stuff that goes after command reading
 fcsChannelPost:
+  rts
   ;;; DO VOLUME
   fcsChanDoVolume:
     ; if (sendVolume || chanVolSpeed[x]!=0)
     lda fcsSendVolume
-    bne fcsChanDoPitch
+    bne +
     lda chanVolSpeed,x
     ora chanVolSpeed+1,x
     beq fcsChanDoPitch
     ; increase volume
-    lda chanVol,x
++   lda chanVol,x
     clc
     adc chanVolSpeed,x
     sta chanVol,x
@@ -506,22 +527,150 @@ fcsChannelPost:
     bpl fcsChanPlus
     fcsChanMinus:
       ; if (chanVol[x]<0)
-      bcc fcs
-      jmp fcsChanDoPitch
+      bcs fcsChanSubmitVol
+      ; chanVol[x]=0
+      lda #0
+      sta chanVol,x
+      sta chanVol+1,x
+      beq fcsChanSubmitVol ; shortcut
     fcsChanPlus:
       ; if (chanVol[x]>=fcsVolMax[x] || CARRY)
+      bcs + ; overflow check
+      lda chanVol+1,x ; comparison check
+      cmp fcsVolMax.w,x
+      bmi fcsChanSubmitVol
+      ; chanVol[x]=fcsVolMax[x]
++     lda fcsVolMax.w,x
+      sta chanVol+1,x
+      lda #0
+      sta chanVol,x
+    fcsChanSubmitVol:
+      lda chanVol+1,x
+      sta fcsArg0
+      ldy #$05 ; volume
+      jsr fcsDispatchCmd
 
   ;;; DO PITCH
   fcsChanDoPitch:
+    ; if (sendPitch || chanVibrato[x]!=0)
+    lda fcsSendPitch
+    bne +
+    lda chanVibrato,x
+    and #$0f ; depth only
+    beq fcsChanDoPorta
+    ; update vibrato
+    ; get vibrato
++   lda chanVibrato,x
+    lsr
+    lsr
+    lsr
+    lsr
+    clc
+    adc chanVibratoPos,x
+    and #$3f
+    sta chanVibratoPos,x 
+    ; calculate vibrato pitch (TODO)
+    ; 1. calculate vibrato position
+    ;   - we use 15 quarter sine tables, one for each vibrato depth
+    ;   - 32-63 are negatives of 0-31
+    ;   - a&31: zero is zero. otherwise a-1 in the table unless a&16
+    ;   - if a&16 then invert a
+    tay
+    ; check for zero in a&31
+    and #$1f
+    bne +
+    ; it is. load zero
+    lda #0
+    jmp fcsPostVibratoCalc1
+    ; it is not. check a&16
++   and #$10
+    bne +
+    ; 0-15
+    dey
+    tya
+    and #$0f
+    jmp fcsPostVibratoCalc
+    ; 16-31
++   tya
+    and #$0f
+    eor #$0f ; 0-15 -> 15-0
+
+    fcsPostVibratoCalc:
+      ; check for 32-63
+      pha
+      tya
+      and #$20
+      bne +
+      ; 0-31
+      pla
+      tay
+      lda (fcsTempPtr),y
+      jmp fcsPostVibratoCalc1
+      ; 32-63 (negate)
++     pla
+      tay
+      lda (fcsTempPtr),y
+      eor #$ff
+      clc
+      adc #1
+
+    ; at this point, a contains the vibrato pitch
+    fcsPostVibratoCalc1:
+      sta fcsArg0
+      ; extend sign
+      bmi +
+      lda #0
+      sta fcsArg0+1
+      beq ++
++     lda #$ff
+      sta fcsArg0+1
+      ; extend pitch sign
+++    lda chanPitch,x
+      sta fcsTempPtr
+      bmi +
+      lda #0
+      sta fcsTempPtr+1
+      beq ++
++     lda #$ff
+      sta fcsTempPtr+1
+      ; add pitch
+++    lda fcsArg0
+      clc
+      adc fcsTempPtr
+      sta fcsArg0
+      lda fcsArg0+1
+      adc fcsTempPtr+1
+      sta fcsArg0+1
+      ; dispatch command
+      ldy #9
+      jsr fcsDispatchCmd
 
   ;;; DO PORTAMENTO
   fcsChanDoPorta:
+    ; if (chanPortaSpeed[x])
+    lda chanPortaSpeed,x
+    beq fcsChanDoArp
+    ; do portamento
+    sta fcsArg0
+    lda #0
+    sta fcsArg0+1
+    lda chanPortaTarget,x
+    sta fcsArg1
+    ldy #8 ; NOTE_PORTA
+    jsr fcsDispatchCmd
+    ; get out (we can't do porta and arp simultaneously)
+    rts
 
   ;;; DO ARPEGGIO
   fcsChanDoArp:
+    ; if (chanArp[x] && !chanPortaSpeed[x])
+    lda chanArp,x
+    beq +
+    ; do arpeggio (TODO)
+    nop
 
   ;;; END
-  rts
++ rts
 
 ; x: channel*2
 fcsDoChannel:
@@ -530,12 +679,7 @@ fcsDoChannel:
   sta fcsSendVolume
   sta fcsSendPitch
 
-  ; check whether this channel is halted (PC = 0)
-  lda chanPC,x
-  ora chanPC+1,x
-  bne +
-  rts
-  ; channel not halted... begin processing
+  ; begin processing
   ; chanTicks--
 + lda chanTicks,x
   sec
@@ -619,14 +763,17 @@ fcsInit:
   ; initialize channel stacks
   lda #0
   ldx #0
+  ldy #0
 - sta chanStackPtr,x
   clc
-  adc #FCS_MAX_STACK
+  adc fcsStackSize.w,y
+  clc
+  adc fcsStackSize.w,y
   inx
   inx
+  iny
   cpx #(FCS_MAX_CHAN*2)
   bne -
-  
 
   ; set volumes
   ; TODO
@@ -637,10 +784,7 @@ fcsInit:
 
 ; floor(127*sin((x/64)*(2*pi)))
 fcsVibTable:
-  .db 0, 12, 24, 36, 48, 59, 70, 80, 89, 98, 105, 112, 117, 121, 124, 126
-  .db 127, 126, 124, 121, 117, 112, 105, 98, 89, 80, 70, 59, 48, 36, 24, 12
-  .db 0, -12, -24, -36, -48, -59, -70, -80, -89, -98, -105, -112, -117, -121, -124, -126
-  .db -126, -126, -124, -121, -117, -112, -105, -98, -89, -80, -70, -59, -48, -36, -24, -12
+  .db 12, 24, 36, 48, 59, 70, 80, 89, 98, 105, 112, 117, 121, 124, 126, 127
 
 ; COMMAND TABLE
 ; $b4 fcsNoArgDispatch,
@@ -957,14 +1101,14 @@ fcsDummyFunc:
   rts
 
 fcsVolMaxExample:
-  .dw $7f00
-  .dw $7f00
-  .dw $7f00
-  .dw $7f00
-  .dw $7f00
-  .dw $7f00
-  .dw $7f00
-  .dw $7f00
+  .db $7f, $00
+  .db $7f, $00
+  .db $7f, $00
+  .db $7f, $00
+  .db $7f, $00
+  .db $7f, $00
+  .db $7f, $00
+  .db $7f, $00
 
 ; first 64 commands
 fcsCmdTableExample: