arm7: decompile SND_unk_037FD440

2 files changed, 907 insertions, 3 deletions

diff --git a/arm7/lib/src/SND_seq.c b/arm7/lib/src/SND_seq.c
index 6421b08f..65ec9d6a 100644
--- a/arm7/lib/src/SND_seq.c
+++ b/arm7/lib/src/SND_seq.c
@@ -33,7 +33,7 @@ void SND_SeqMain(BOOL step) {
         if (ply->flags.prepared) {
             if (step && !ply->flags.paused)
                 PlayerSeqMain(ply);
-            PlayerUpdateChannelVolume(ply);
+            PlayerUpdateChannel(ply);
         }
 
         if (ply->flags.active)
@@ -50,7 +50,7 @@ void SND_PrepareSeq(int player, const void *seq, u32 offset, struct SNDBankData
     if (ply->flags.active)
         PlayerStop(ply);
     
-    PlayerSetBank(ply, bankData);
+    PlayerInit(ply, bankData);
 
     int allocTrkIdx = AllocateTrack();
 
@@ -59,7 +59,7 @@ void SND_PrepareSeq(int player, const void *seq, u32 offset, struct SNDBankData
     
     struct SNDTrack *trk = &SNDi_Work.tracks[allocTrkIdx];
     TrackInit(trk);
-    TrackSetSeq(trk, seq, offset);
+    TrackStart(trk, seq, offset);
     ply->tracks[0] = (u8)allocTrkIdx;
     SeqCacheFetch(trk->cur);
 
diff --git a/arm7/lib/src/SND_unk_037FD440.c b/arm7/lib/src/SND_unk_037FD440.c
new file mode 100644
index 00000000..253ccecb
--- /dev/null
+++ b/arm7/lib/src/SND_unk_037FD440.c
@@ -0,0 +1,904 @@
+#include "SND_unk_037FD440.h"
+
+#include "SND_util.h"
+#include "SND_lfo.h"
+#include "SND_exChannel.h"
+#include "SND_bank.h"
+
+#define SND_TRACK_MUTE_MODE_UNMUTE 0
+#define SND_TRACK_MUTE_MODE_MUTE 1
+#define SND_TRACK_MUTE_MODE_MUTE_RELEASE 2
+#define SND_TRACK_MUTE_MODE_MUTE_STOP 3
+
+enum SNDSeqProc {
+    SND_PROC_SKIP_NOTES = 0,
+    SND_PROC_PLAY_NOTES = 1,
+};
+
+enum SNDSeqVal {
+    SND_SEQ_VAL_U8  = 0,
+    SND_SEQ_VAL_U16 = 1,
+    SND_SEQ_VAL_VLV = 2,
+    SND_SEQ_VAL_RAN = 3,
+    SND_SEQ_VAL_VAR = 4,
+};
+
+#define SND_TIMER_RATE 240
+
+static struct {
+    const u8 *begin;
+    const u8 *end;
+    union {
+        u8 buf[16];
+        u32 buf32[4];
+    };
+} sSeqCache;
+static int sPrintEnabled;
+
+
+
+static s16 *PlayerGetVariablePointer(const struct SNDPlayer *player, int var);
+static void TrackUpdateChannel(struct SNDTrack *track, struct SNDPlayer *player, int release);
+
+// TODO make static
+void SeqCacheFetch(const u8 *addr) {
+    addr = (const u8 *)((u32)addr & ~3);
+    sSeqCache.begin = addr;
+    sSeqCache.end = sSeqCache.begin + 16;
+
+    const u32 *src = (const u32 *)addr;
+
+    sSeqCache.buf32[0] = src[0];
+    sSeqCache.buf32[1] = src[1];
+    sSeqCache.buf32[2] = src[2];
+    sSeqCache.buf32[3] = src[3];
+}
+
+// TODO make static
+u8 SeqReadByte(const u8 *addr) {
+    if (addr < sSeqCache.begin || addr >= sSeqCache.end)
+        SeqCacheFetch(addr);
+    
+    return sSeqCache.buf[(u32)addr - (u32)sSeqCache.begin];
+}
+
+static inline u8 TrackReadU8(struct SNDTrack *track) {
+    u8 retval = SeqReadByte(track->cur);
+    track->cur++;
+    return retval;
+}
+
+// TODO make static
+u16 TrackReadU16(struct SNDTrack *track) {
+    int retval;
+
+    retval = TrackReadU8(track);
+    retval |= TrackReadU8(track) << 8;
+
+    return (u16)retval;
+}
+
+static u32 TrackReadU24(struct SNDTrack *track) {
+    u32 retval;
+
+    retval = TrackReadU8(track);
+    retval |= TrackReadU8(track) << 8;
+    retval |= TrackReadU8(track) << 16;
+
+    return retval;
+}
+
+static int TrackReadVLV(struct SNDTrack *track) {
+    int retval = 0;
+    int b;
+
+    do {
+        b = TrackReadU8(track);
+        retval = (retval << 7) | (b & 0x7F);
+    } while(b & 0x80);
+
+    return retval;
+}
+
+static int TrackParseValue(struct SNDTrack *track, struct SNDPlayer *player, int valueType) {
+    int retval;
+    int hi;
+    int lo;
+    int ran;
+    s16 *var;
+
+    // BUG: undefined behavior if invalid valueType is passed (uninitialized return value)
+
+    switch (valueType) {
+    case SND_SEQ_VAL_U8:
+        retval = TrackReadU8(track);
+        break;
+    case SND_SEQ_VAL_U16:
+        retval = TrackReadU16(track);
+        break;
+    case SND_SEQ_VAL_VLV:
+        retval = TrackReadVLV(track);
+        break;
+    case SND_SEQ_VAL_VAR:
+        var = PlayerGetVariablePointer(player, TrackReadU8(track));
+        if (var)
+            retval = *var;
+        break;
+    case SND_SEQ_VAL_RAN:
+        lo = TrackReadU16(track) << 16;
+        hi = (s16)TrackReadU16(track);
+        ran = SND_CalcRandom();
+        retval = hi - (lo >> 16);
+        retval += 1;
+        retval = (ran * retval) >> 16;
+        retval += lo >> 16;
+        break;
+    }
+    
+    return retval;
+}
+
+// TODO make static
+void TrackInit(struct SNDTrack *track) {
+    track->base = NULL;
+    track->cur = NULL;
+
+    track->flags.noteWait = TRUE;
+    track->flags.muted = FALSE;
+    track->flags.tie = FALSE;
+    track->flags.noteFinishWait = FALSE;
+    track->flags.portamento = FALSE;
+    track->flags.cmp = TRUE;
+    track->flags.channelMask = FALSE;
+
+    track->callStackDepth = 0;
+    track->program = 0;
+    track->priority = 64;
+    track->volume = 127;
+    track->expression = 127;
+    track->extFader = 0;
+    track->pan = 0;
+    track->extPan = 0;
+    track->pitchBend = 0;
+    track->extPitch = 0;
+    track->envAttack = 255;
+    track->envDecay = 255;
+    track->envSustain = 255;
+    track->envRelease = 255;
+    track->panRange = 127;
+    track->bendRange = 2;
+    track->portamentoKey = 60;
+    track->portamentoTime = 0;
+    track->sweepPitch = 0;
+    track->transpose = 0;
+    track->channelMask = 0xFFFF;
+    SND_InitLfoParam(&track->mod);
+    track->wait = 0;
+    track->channelLLHead = NULL;
+}
+
+// TODO make static
+void TrackStart(struct SNDTrack *track, const void *seq, u32 offset) {
+    track->base = (const u8 *)seq;
+    track->cur = &track->base[offset];
+}
+
+// TODO make static later
+void PlayerInit(struct SNDPlayer *player, struct SNDBankData *bank) {
+    player->flags.paused = FALSE;
+    player->bank = bank;
+    player->tempo = 120;
+    player->tempoRatio = 256;
+    player->tempoCounter = SND_TIMER_RATE;
+    player->volume = 0x7F;
+    player->extFader = 0;
+    player->prio = 64;
+
+    for (int i = 0; i < SND_TRACK_COUNT_PER_PLAYER; i++) {
+        player->tracks[i] = 0xFF;
+    }
+
+    if (SNDi_SharedWork) {
+        SNDi_SharedWork->players[player->playerId].tickCounter = 0;
+
+        for (int i = 0; i < SND_TRACK_COUNT_PER_PLAYER; i++) {
+            SNDi_SharedWork->players[player->playerId].localVars[i] = -1;
+        }
+    }
+}
+
+// TODO make static
+void TrackReleaseChannels(struct SNDTrack *track, struct SNDPlayer *player, int release) {
+    TrackUpdateChannel(track, player, 0);
+
+    for (struct SNDExChannel *chn = track->channelLLHead; chn; chn = chn->channelLLNext) {
+        if (SND_IsExChannelActive(chn)) {
+            if (release >= 0)
+                SND_SetExChannelRelease(chn, release & 0xFF);
+            chn->priority = 1;
+            SND_ReleaseExChannel(chn);
+        }
+    }
+}
+
+// TODO make static
+void TrackFreeChannels(struct SNDTrack *track) {
+    for (struct SNDExChannel *chn = track->channelLLHead; chn; chn = chn->channelLLNext) {
+        SND_FreeExChannel(chn);
+    }
+
+    track->channelLLHead = NULL;
+}
+
+void PlayerSeqMain(struct SNDPlayer *player) {
+    int ticks = 0;
+    int tempoInc;
+    int i;
+
+    while (player->tempoCounter >= SND_TIMER_RATE) {
+        player->tempoCounter -= SND_TIMER_RATE;
+        ticks++;
+    }
+
+    for (i = 0; i < ticks; i++) {
+        if (PlayerStepTicks(player, SND_PROC_PLAY_NOTES)) {
+            PlayerStop(player);
+            break;
+        }
+    }
+
+    if (SNDi_SharedWork) {
+        SNDi_SharedWork->players[player->playerId].tickCounter += i;
+    }
+
+    tempoInc = player->tempo;
+    tempoInc *= player->tempoRatio;
+    tempoInc >>= 8;
+
+    player->tempoCounter += tempoInc;
+}
+
+struct SNDTrack *PlayerGetTrack(struct SNDPlayer *player, int track) {
+    if (track > (SND_TRACK_COUNT_PER_PLAYER - 1))
+        return NULL;
+    
+    if (player->tracks[track] == 0xFF)
+        return NULL;
+    
+    return &SNDi_Work.tracks[player->tracks[track]];
+}
+
+static void TrackStop(struct SNDTrack *track, struct SNDPlayer *player) {
+    TrackReleaseChannels(track, player, -1);
+    TrackFreeChannels(track);
+}
+
+static void PlayerStopTrack(struct SNDPlayer *player, int trackIdx) {
+    struct SNDTrack *track = PlayerGetTrack(player, trackIdx);
+
+    if (track == NULL)
+        return;
+    
+    TrackStop(track, player);
+    SNDi_Work.tracks[player->tracks[trackIdx]].flags.active = FALSE;
+    player->tracks[trackIdx] = 0xFF;
+}
+
+void PlayerStop(struct SNDPlayer *player) {
+    for (int i = 0; i < SND_TRACK_COUNT_PER_PLAYER; i++) {
+        PlayerStopTrack(player, i);
+    }
+    player->flags.active = FALSE;
+}
+
+static void ChannelCallback(struct SNDExChannel *chn, int status, void *track_) {
+    struct SNDExChannel *cur;
+    struct SNDTrack *track;
+    
+    track = (struct SNDTrack *)track_;
+
+    if (status == 1) {
+        chn->priority = 0;
+        SND_FreeExChannel(chn);
+    }
+
+    if (track->channelLLHead == chn) {
+        track->channelLLHead = chn->channelLLNext;
+    } else {
+        cur = track->channelLLHead;
+
+        while (cur->channelLLNext) {
+            if (cur->channelLLNext == chn) {
+                cur->channelLLNext = chn->channelLLNext;
+                return;
+            }
+            cur = cur->channelLLNext;
+        }
+    }
+}
+
+static void TrackUpdateChannel(struct SNDTrack *track, struct SNDPlayer *player, int release) {
+    int vol;
+    int fader;
+    int pan;
+    int pitch;
+
+    vol = SNDi_DecibelSquareTable[track->volume] +
+        SNDi_DecibelSquareTable[track->expression] +
+        SNDi_DecibelSquareTable[player->volume];
+
+    fader = track->extFader + player->extFader;
+
+    pitch = track->pitchBend;
+    pitch *= track->bendRange << 6;
+    pitch >>= 7;
+    pitch += track->extPitch;
+
+    pan = track->pan;
+
+    if (track->panRange != 127)
+        pan = (pan * track->panRange + 0x40) >> 7;
+    
+    pan += track->extPan;
+
+    if (vol < -0x8000)
+        vol = -0x8000;
+    
+    if (fader < -0x8000)
+        fader = -0x8000;
+    
+    if (pan < -128)
+        pan = -128;
+    else if (pan > 127)
+        pan = 127;
+    
+    for (struct SNDExChannel *chn = track->channelLLHead; chn != NULL; chn = chn->channelLLNext) {
+        chn->userDecay2 = (short)fader;
+
+        if (chn->envStatus == 3)
+            continue;
+
+        chn->userDecay = (s16)vol;
+        chn->userPitch = (s16)pitch;
+        chn->userPan = (s8)pan;
+        chn->panRange = track->panRange;
+        chn->lfo.param = track->mod;
+
+        if (chn->length == 0 && release != 0) {
+            chn->priority = 1;
+            SND_ReleaseExChannel(chn);
+        }
+    }
+}
+
+// TODO make static
+void PlayerUpdateChannel(struct SNDPlayer *player) {
+    for (int i = 0; i < SND_TRACK_COUNT_PER_PLAYER; i++) {
+        struct SNDTrack *trk = PlayerGetTrack(player, i);
+        if (trk) {
+            TrackUpdateChannel(trk, player, 1);
+        }
+    }
+}
+
+static void TrackPlayNote(struct SNDTrack *track, struct SNDPlayer *player, int midiKey, int velocity, int length) {
+    struct SNDExChannel *chn = NULL;
+
+    if (track->flags.tie) {
+        chn = track->channelLLHead;
+        if (chn) {
+            chn->midiKey = (u8)midiKey;
+            chn->velocity = (u8)velocity;
+        }
+    }
+
+    if (chn == NULL) {
+        struct SNDInstData inst;
+        if (!SND_ReadInstData(player->bank, track->program, midiKey, &inst))
+            return;
+
+        u32 allowedChannels;
+
+        switch (inst.type) {
+        case SND_INST_PCM:
+        case SND_INST_DIRECTPCM:
+            // all channels support PCM
+            allowedChannels = 0xFFFF;
+            break;
+        case SND_INST_PSG:
+            // only channels 8, 9, 10, 11, 12, 13 support PSG
+            allowedChannels = 0x3F00;
+            break;
+        case SND_INST_NOISE:
+            // only channels 14 and 15 support noise
+            allowedChannels = 0xC000;
+            break;
+        default:
+            return;
+        }
+
+        allowedChannels &= track->channelMask;
+
+        chn = SND_AllocExChannel(allowedChannels, player->prio + track->priority, track->flags.channelMask, ChannelCallback, track);
+        if (chn == NULL)
+            return;
+        
+        if (!SND_NoteOn(chn, midiKey, velocity, track->flags.tie ? -1 : length, player->bank, &inst)) {
+            chn->priority = 0;
+            SND_FreeExChannel(chn);
+            return;
+        }
+
+        chn->channelLLNext = track->channelLLHead;
+        track->channelLLHead = chn;
+    }
+
+    if (track->envAttack != 0xFF)
+        SND_SetExChannelAttack(chn, track->envAttack);
+    
+    if (track->envDecay != 0xFF)
+        SND_SetExChannelDecay(chn, track->envDecay);
+
+    if (track->envSustain != 0xFF)
+        SND_SetExChannelSustain(chn, track->envSustain);
+
+    if (track->envRelease != 0xFF)
+        SND_SetExChannelRelease(chn, track->envRelease);
+    
+    chn->sweepPitch = track->sweepPitch;
+    if (track->flags.portamento)
+        chn->sweepPitch += (short)((track->portamentoKey - midiKey) << 6);
+    
+    if (track->portamentoTime == 0) {
+        chn->sweepLength = length;
+        chn->flags.autoSweep = FALSE;
+    } else {
+        int swp = track->portamentoTime * track->portamentoTime;
+        swp *= chn->sweepPitch < 0 ? -chn->sweepPitch : chn->sweepPitch;
+        swp >>= 11;
+        chn->sweepLength = swp;
+    }
+
+    chn->sweepCounter = 0;
+}
+
+static int TrackStepTicks(struct SNDTrack *track, struct SNDPlayer *player, int trackIdx, u32 playNotes) {
+    (void)trackIdx;
+
+    struct SNDExChannel *chn;
+    u8 cmd;
+    enum SNDSeqVal valueType;
+    BOOL specialValueType;
+    BOOL runCmd;
+    s32 length;
+    int midiKey;
+
+    s32 par;
+
+
+    for (chn = track->channelLLHead; chn; chn = chn->channelLLNext) {
+        if (chn->length > 0)
+            chn->length--;
+        
+        if (!chn->flags.autoSweep && chn->sweepCounter < chn->sweepLength)
+            chn->sweepCounter++;
+    }
+
+    if (track->flags.noteFinishWait) {
+        if (track->channelLLHead)
+            return 0;
+        track->flags.noteFinishWait = FALSE;
+    }
+
+    if (track->wait > 0) {
+        track->wait--;
+        if (track->wait > 0)
+            return 0;
+    }
+
+    SeqCacheFetch(track->cur);
+
+    while (track->wait == 0 && !track->flags.noteFinishWait) {
+        specialValueType = FALSE;
+        runCmd = TRUE;
+
+        cmd = TrackReadU8(track);
+
+        if (cmd == 0xA2) {
+            cmd = TrackReadU8(track);
+            runCmd = track->flags.cmp;
+        }
+
+        if (cmd == 0xA0) {
+            cmd = TrackReadU8(track);
+            valueType = SND_SEQ_VAL_RAN;
+            specialValueType = TRUE;
+        }
+
+        if (cmd == 0xA1) {
+            cmd = TrackReadU8(track);
+            valueType = SND_SEQ_VAL_VAR;
+            specialValueType = TRUE;
+        }
+
+        if ((cmd & 0x80) == 0) {
+            par = TrackReadU8(track);
+
+            length = TrackParseValue(track, player, specialValueType ? valueType : SND_SEQ_VAL_VLV);
+            midiKey = cmd + track->transpose;
+
+            if (!runCmd)
+                continue;
+            
+            if (midiKey < 0)
+                midiKey = 0;
+            else if (midiKey > 127) {
+                midiKey = 127;
+            }
+
+            if (!track->flags.muted && playNotes != 0) {
+                TrackPlayNote(track, player, midiKey, par, (length > 0) ? length : -1);
+            }
+            
+            track->portamentoKey = (u8)midiKey;
+
+            if (track->flags.noteWait) {
+                track->wait = length;
+                if (length == 0) {
+                    track->flags.noteFinishWait = TRUE;
+                }
+            }
+
+            continue;
+        }
+
+        switch (cmd & 0xF0) {
+        case 0x80:
+            par = TrackParseValue(track, player, specialValueType ? valueType : SND_SEQ_VAL_VLV);
+            if (!runCmd)
+                break;
+            
+            switch (cmd) {
+            case 0x80:
+                track->wait = par;
+                break;
+            case 0x81:
+                if (par < 0x10000)
+                    track->program = (u16)par;
+                break;
+            }
+            break;
+        case 0x90:
+            switch (cmd) {
+            case 0x93:
+                {
+                    u32 off;
+                    struct SNDTrack *newTrack;
+
+                    par = TrackReadU8(track);
+                    off = TrackReadU24(track);
+                    if (!runCmd)
+                        break;
+
+                    newTrack = PlayerGetTrack(player, par);
+                    if (newTrack && newTrack != track) {
+                        TrackStop(newTrack, player);
+                        TrackStart(newTrack, track->base, off);
+                    }
+                }
+                break;
+            case 0x94:
+                {
+                    u32 off = TrackReadU24(track);
+                    if (!runCmd)
+                        break;
+                    track->cur = &track->base[off];
+                }
+                break;
+            case 0x95:
+                {
+                    u32 off = TrackReadU24(track);
+                    if (!runCmd)
+                        break;
+
+                    if (track->callStackDepth < SND_TRACK_MAX_CALL) {
+                        track->posCallStack[track->callStackDepth] = track->cur;
+                        track->callStackDepth++;
+                        track->cur = &track->base[off];
+                    }
+                    break;
+                }
+            }
+            break;
+        case 0xC0:
+        case 0xD0:
+            {
+                union {
+                    u8 _u8;
+                    s8 _s8;
+                } par;
+                par._u8 = (u8)TrackParseValue(track, player, specialValueType ? valueType : SND_SEQ_VAL_U8);
+                if (!runCmd)
+                    break;
+
+                switch (cmd) {
+                case 0xC1:
+                    track->volume = par._u8;
+                    break;
+                case 0xD5:
+                    track->expression = par._u8;
+                    break;
+                case 0xC2:
+                    player->volume = par._u8;
+                    break;
+                case 0xC5:
+                    track->bendRange = par._u8;
+                    break;
+                case 0xC6:
+                    track->priority = par._u8;
+                    break;
+                case 0xC7:
+                    track->flags.noteWait = par._u8;
+                    break;
+                case 0xCF:
+                    track->portamentoTime = par._u8;
+                    break;
+                case 0xCA:
+                    track->mod.depth = par._u8;
+                    break;
+                case 0xCB:
+                    track->mod.speed = par._u8;
+                    break;
+                case 0xCC:
+                    track->mod.target = par._u8;
+                    break;
+                case 0xCD:
+                    track->mod.range = par._u8;
+                    break;
+                case 0xD0:
+                    track->envAttack = par._u8;
+                    break;
+                case 0xD1:
+                    track->envDecay = par._u8;
+                    break;
+                case 0xD2:
+                    track->envSustain = par._u8;
+                    break;
+                case 0xD3:
+                    track->envRelease = par._u8;
+                    break;
+                case 0xD4:
+                    if (track->callStackDepth < SND_TRACK_MAX_CALL) {
+                        track->posCallStack[track->callStackDepth] = track->cur;
+                        track->loopCount[track->callStackDepth] = par._u8;
+                        track->callStackDepth++;
+                    }
+                    break;
+                case 0xC8:
+                    track->flags.tie = par._u8;
+                    TrackReleaseChannels(track, player, -1);
+                    TrackFreeChannels(track);
+                    break;
+                case 0xD7:
+                    TrackMute(track, player, par._u8);
+                    break;
+                case 0xC9:
+                    track->portamentoKey = (u8)(par._u8 + track->transpose);
+                    track->flags.portamento = TRUE;
+                    break;
+                case 0xCE:
+                    track->flags.portamento = par._u8;
+                    break;
+                case 0xC3:
+                    track->transpose = par._s8;
+                    break;
+                case 0xC4:
+                    track->pitchBend = par._s8;
+                    break;
+                case 0xC0:
+                    track->pan = (s8)(par._u8 - 0x40);
+                    break;
+                case 0xD6:
+                    {
+                        s16 *varPtr;
+
+                        if (sPrintEnabled) {
+                            varPtr = PlayerGetVariablePointer(player, par._u8);
+                        }
+                    }
+                    break;
+                }
+            }
+            break;
+        case 0xE0:
+            {
+                s16 par = (s16)TrackParseValue(track, player, specialValueType ? valueType : SND_SEQ_VAL_U16);
+                if (!runCmd)
+                    break;
+
+                switch (cmd) {
+                case 0xE3:
+                    track->sweepPitch = par;
+                    break;
+                case 0xE1:
+                    player->tempo = (u16)par;
+                    break;
+                case 0xE0:
+                    track->mod.delay = (u16)par;
+                    break;
+                }
+            }
+            break;
+        case 0xB0:
+            {
+                // TODO fix refalloc -> stack on varNum
+                int varNum = TrackReadU8(track);
+
+                s16 par = (s16)TrackParseValue(track, player, specialValueType ? valueType : SND_SEQ_VAL_U16);
+                s16 *varPtr = PlayerGetVariablePointer(player, varNum);
+
+                if (!runCmd)
+                    break;
+
+                if (varPtr == NULL)
+                    break;
+
+                switch (cmd) {
+                case 0xB0:
+                    *varPtr = par;
+                    break;
+                case 0xB1:
+                    *varPtr += par;
+                    break;
+                case 0xB2:
+                    *varPtr -= par;
+                    break;
+                case 0xB3:
+                    *varPtr *= par;
+                    break;
+                case 0xB4:
+                    if (par != 0)
+                        *varPtr /= par;
+                    break;
+                case 0xB5:
+                    if (par >= 0)
+                        *varPtr <<= par;
+                    else
+                        *varPtr >>= -par;
+                    break;
+                case 0xB6:
+                    {
+                        BOOL neg = FALSE;
+                        if (par < 0) {
+                            neg = TRUE;
+                            par = (s16)(-par);
+                        }
+                        s32 random = SND_CalcRandom();
+                        random = (random * (par + 1)) >> 16;
+                        if (neg)
+                            random = -random;
+                        *varPtr = (s16)random;
+                    }
+                    break;
+                case 0xB7:
+                    break;
+                case 0xB8:
+                    track->flags.cmp = *varPtr == par;
+                    break;
+                case 0xB9:
+                    track->flags.cmp = *varPtr >= par;
+                    break;
+                case 0xBA:
+                    track->flags.cmp = *varPtr > par;
+                    break;
+                case 0xBB:
+                    track->flags.cmp = *varPtr <= par;
+                    break;
+                case 0xBC:
+                    track->flags.cmp = *varPtr < par;
+                    break;
+                case 0xBD:
+                    track->flags.cmp = *varPtr != par;
+                    break;
+                }
+            }
+            break;
+        case 0xF0:
+            if (!runCmd)
+                break;
+            
+            switch (cmd) {
+            case 0xFD:
+                if (track->callStackDepth != 0) {
+                    track->callStackDepth--;
+                    track->cur = track->posCallStack[track->callStackDepth];
+                }
+                break;
+            case 0xFC:
+                {
+                    if (track->callStackDepth == 0)
+                        break;
+
+                    // gosh, this was nasty to figure out
+                    u8 loopCount = track->loopCount[track->callStackDepth - 1];
+                    if (loopCount != 0) {
+                        loopCount--;
+                        if (loopCount == 0) {
+                            track->callStackDepth--;
+                            break;
+                        }
+                    }
+                    track->loopCount[track->callStackDepth - 1] = loopCount;
+                    track->cur = track->posCallStack[track->callStackDepth - 1];
+                }
+                break;
+            case 0xFE:
+                break;
+            case 0xFF:
+                return -1;
+            }
+            break;
+        }
+    }
+
+    return 0;
+}
+
+BOOL PlayerStepTicks(struct SNDPlayer *player, u32 ticks) {
+    BOOL isPlaying = FALSE;
+
+    for (int i = 0; i < SND_TRACK_COUNT_PER_PLAYER; i++) {
+        struct SNDTrack *trk = PlayerGetTrack(player, i);
+
+        if (trk && trk->cur) {
+            if (TrackStepTicks(trk, player, i, ticks))
+                PlayerStopTrack(player, i);
+            else
+                isPlaying = TRUE;
+        }
+    }
+
+    return !isPlaying;
+}
+
+static s16 *PlayerGetVariablePointer(const struct SNDPlayer *player, int var) {
+    if (SNDi_SharedWork == NULL)
+        return NULL;
+    else if (var < 16) {
+        return &SNDi_SharedWork->players[player->playerId].localVars[var];
+    } else {
+        return &SNDi_SharedWork->globalVars[var - 16];
+    }
+}
+
+int AllocateTrack(void) {
+    for (int i = 0; i < SND_TRACK_COUNT; i++) {
+        if (!SNDi_Work.tracks[i].flags.active) {
+            SNDi_Work.tracks[i].flags.active = TRUE;
+            return i;
+        }
+    }
+
+    return -1;
+}
+
+// TODO make static after merging with SND_seq
+void TrackMute(struct SNDTrack *track, struct SNDPlayer *player, int muteMode) {
+    switch (muteMode) {
+    case SND_TRACK_MUTE_MODE_UNMUTE:
+        track->flags.muted = FALSE;
+        break;
+    case SND_TRACK_MUTE_MODE_MUTE:
+        track->flags.muted = TRUE;
+        break;
+    case SND_TRACK_MUTE_MODE_MUTE_RELEASE:
+        track->flags.muted = TRUE;
+        TrackReleaseChannels(track, player, -1);
+        break;
+    case SND_TRACK_MUTE_MODE_MUTE_STOP:
+        track->flags.muted = TRUE;
+        TrackReleaseChannels(track, player, 127);
+        TrackFreeChannels(track);
+        break;
+    }
+}