AHX.c

/*
# _____     ___ ____     ___ ____
#  ____|   |    ____|   |        | |____|
# |     ___|   |____ ___|    ____| |    \    PS2DEV Open Source Project.
#-----------------------------------------------------------------------
# Copyright 2001-2004, ps2dev - http://www.ps2dev.org
# Licenced under Academic Free License version 2.0
# Review ps2sdk README & LICENSE files for further details.
*/
 
#include <stdio.h>
#include <sysclib.h>
#include <sysmem.h>
#include "ahx.h"
 
// if this is defined the irx will be compiled without PRINTF output
#define COMPACT_CODE
 
#define malloc(size) \
    (AllocSysMemory(0, size, NULL))
 
#define free(ptr) \
    (FreeSysMemory(ptr))
 
#define Period2Freq(period) (3579545 / (period)) // accurate enough ;)
#define min(a, b)           (((a) < (b)) ? (a) : (b))
#define AHXOF_BOOST         0
#define AHXOI_OVERSAMPLING  1
 
int VibratoTable[] = {
    0, 24, 49, 74, 97, 120, 141, 161, 180, 197, 212, 224, 235, 244, 250, 253, 255,
    253, 250, 244, 235, 224, 212, 197, 180, 161, 141, 120, 97, 74, 49, 24,
    0, -24, -49, -74, -97, -120, -141, -161, -180, -197, -212, -224, -235, -244, -250, -253, -255,
    -253, -250, -244, -235, -224, -212, -197, -180, -161, -141, -120, -97, -74, -49, -24};
 
int PeriodTable[] = {
    0x0000, 0x0D60, 0x0CA0, 0x0BE8, 0x0B40, 0x0A98, 0x0A00, 0x0970,
    0x08E8, 0x0868, 0x07F0, 0x0780, 0x0714, 0x06B0, 0x0650, 0x05F4,
    0x05A0, 0x054C, 0x0500, 0x04B8, 0x0474, 0x0434, 0x03F8, 0x03C0,
    0x038A, 0x0358, 0x0328, 0x02FA, 0x02D0, 0x02A6, 0x0280, 0x025C,
    0x023A, 0x021A, 0x01FC, 0x01E0, 0x01C5, 0x01AC, 0x0194, 0x017D,
    0x0168, 0x0153, 0x0140, 0x012E, 0x011D, 0x010D, 0x00FE, 0x00F0,
    0x00E2, 0x00D6, 0x00CA, 0x00BE, 0x00B4, 0x00AA, 0x00A0, 0x0097,
    0x008F, 0x0087, 0x007F, 0x0078, 0x0071};
 
int Offsets[] = {0x00, 0x04, 0x04 + 0x08, 0x04 + 0x08 + 0x10, 0x04 + 0x08 + 0x10 + 0x20, 0x04 + 0x08 + 0x10 + 0x20 + 0x40};
 
int *MixingBuffer;
int BlockLen;
int VolumeTable[65][256];
char VoiceBuffer[0x281]; // for oversampling optimization!
char *WaveformTab[4];
struct AHXVoice Voices[4];
struct AHXSong Song;
struct AHXWaves *Waves;
struct AHXPosition *Positions;
struct AHXStep **Tracks;
struct AHXInstrument *Instruments;
 
short insrument_count = 0;
short position_count  = 0;
short step_count      = 0;
 
int pos[4] = {0, 0, 0, 0}; // global to retain 'static' properties
 
// Player vars
int StepWaitFrames, GetNewPosition, SongEndReached, TimingValue;
int PatternBreak;
int MainVolume;
int Playing, Tempo;
int PosNr, PosJump;
int NoteNr, PosJumpNote;
int WNRandom;
int PlayingTime;
 
// Output vars
int Oversampling = 0;
int Boost        = 0;
#define Bits      16
#define Frequency 48000
#define MixLen    2
#define Hz        50
#define BlockLen  3840
int Paused;
 
// AHXWaves ////////////////////////////////////////////////////////////////////////////////////////////////
 
void GenerateTriangle(char *Buffer, int Len)
{
    int d2    = Len;
    int d5    = d2 >> 2;
    int d1    = 128 / d5;
    int d4    = -(d2 >> 1);
    char *edi = Buffer;
    char *esi;
    int eax = 0;
    int ecx;
    for (ecx = 0; ecx < d5; ecx++) {
        *edi++ = eax;
        eax += d1;
    }
    *edi++ = 0x7f;
    if (d5 != 1) {
        eax = 128;
        for (ecx = 0; ecx < d5 - 1; ecx++) {
            eax -= d1;
            *edi++ = eax;
        }
    }
    esi = edi + d4;
    for (ecx = 0; ecx < d5 * 2; ecx++) {
        *edi++ = *esi++;
        if (edi[-1] == 0x7f)
            edi[-1] = 0x80;
        else
            edi[-1] = -edi[-1];
    }
}
 
void GenerateSquare(char *Buffer)
{
    char *edi = Buffer;
    int ebx, ecx;
    for (ebx = 1; ebx <= 0x20; ebx++) {
        for (ecx = 0; ecx < (0x40 - ebx) * 2; ecx++)
            *edi++ = 0x80;
        for (ecx = 0; ecx < ebx * 2; ecx++)
            *edi++ = 0x7f;
    }
}
 
void GenerateSawtooth(char *Buffer, int Len)
{
    char *edi = Buffer;
    int ecx;
    int ebx = 256 / (Len - 1), eax = -128;
    for (ecx = 0; ecx < Len; ecx++) {
        *edi++ = eax;
        eax += ebx;
    }
}
 
void GenerateWhiteNoise(char *Buffer, int Len)
{
    unsigned int Seed = 0x41595321;
 
    while (Len--) {
        if (Seed & 0x100)
            *Buffer = (char)(Seed & 0xff);
        else if (!(Seed & 0xffff))
            *Buffer = 0x80;
        else
            *Buffer = 0x7f;
 
        Buffer++;
        unsigned int tmp = Seed; // ror 5
        Seed >>= 5;
        tmp <<= 31 - 5;
        Seed |= tmp;
        Seed              = Seed ^ 0x9a;
        unsigned int tmp2 = tmp = Seed; // rol 2
        Seed <<= 2;
        tmp >>= 31 - 2;
        Seed |= tmp;
        Seed += tmp2;
        tmp = Seed ^ tmp2; // ror 5
        Seed >>= 3;
        tmp <<= 31 - 3;
        Seed |= tmp;
    }
}
 
// AHXVoice ////////////////////////////////////////////////////////////////////////////////////////////////
 
void AHXVoice_Init(struct AHXVoice *pVoice)
{
    memset(pVoice, 0, sizeof(struct AHXVoice));
    memset(pVoice->VoiceBuffer, 0, 0x281);
    pVoice->TrackOn           = 1;
    pVoice->TrackMasterVolume = 0x40;
}
 
void AHXVoice_CalcADSR(struct AHXVoice *pVoice)
{
    pVoice->ADSR.aFrames = pVoice->Instrument->Envelope.aFrames;
    pVoice->ADSR.aVolume = pVoice->Instrument->Envelope.aVolume * 256 / pVoice->ADSR.aFrames;
    pVoice->ADSR.dFrames = pVoice->Instrument->Envelope.dFrames;
    pVoice->ADSR.dVolume = (pVoice->Instrument->Envelope.dVolume - pVoice->Instrument->Envelope.aVolume) * 256 / pVoice->ADSR.dFrames;
    pVoice->ADSR.sFrames = pVoice->Instrument->Envelope.sFrames;
    pVoice->ADSR.rFrames = pVoice->Instrument->Envelope.rFrames;
    pVoice->ADSR.rVolume = (pVoice->Instrument->Envelope.rVolume - pVoice->Instrument->Envelope.dVolume) * 256 / pVoice->ADSR.rFrames;
}
 
// AHXPlayer ///////////////////////////////////////////////////////////////////////////////////////////////
 
#ifdef WIN32
#pragma warning(disable : 4309 4305)
#endif
 
#define FIXEDPOINT 16 // 16 = 32-FIXEDPOINT.FIXEDPOINT
 
void clipint(int *x)
{
    if (*x > (int)((u32)(127) << FIXEDPOINT)) {
        *x = (int)((u32)(127) << FIXEDPOINT);
        return;
    }
    if (*x < (int)((u32)(-128) << FIXEDPOINT)) {
        *x = (int)((u32)(-128) << FIXEDPOINT);
        return;
    }
}
 
void GenerateFilterWaveforms(char *Buffer, char *Low, char *High)
{
    const int LengthTable[] = {3, 7, 0xf, 0x1f, 0x3f, 0x7f, 3, 7, 0xf, 0x1f, 0x3f, 0x7f,
                               0x7f, 0x7f, 0x7f, 0x7f, 0x7f, 0x7f, 0x7f, 0x7f, 0x7f, 0x7f, 0x7f, 0x7f, 0x7f, 0x7f, 0x7f, 0x7f, 0x7f, 0x7f, 0x7f, 0x7f,
                               0x7f, 0x7f, 0x7f, 0x7f, 0x7f, 0x7f, 0x7f, 0x7f, 0x7f, 0x7f, 0x7f, 0x7f,
                               (0x280 * 3) - 1};
    int temp, freq, waves, i, highint, midint, lowint;
 
    for (temp = 0, freq = 8; temp < 31; temp++, freq += 3) {
        char *a0 = Buffer;
        // fre        = ((freq * 1.25f) / 100);
        int v125   = (1 << FIXEDPOINT) + ((1 << FIXEDPOINT) / 4);
        int freint = ((freq * v125) / 100);                  // 0x14000 ~ 1.25
        for (waves = 0; waves < 6 + 6 + 0x20 + 1; waves++) { // 0 - 44
            // mid    = 0.f;
            // low    = 0.f;
            midint = 0;
            lowint = 0;
 
            for (i = 0; i <= LengthTable[waves]; i++) {
                // high = a0[i] - mid - low;
                // clip(&high);
                // mid += high * fre;
                // clip(&mid);
                // low += mid * fre;
                // clip(&low);
 
                highint = (((int)(a0[i])) << FIXEDPOINT) - midint - lowint;
                clipint(&highint);
                midint += (highint * (freint >> (FIXEDPOINT / 2)) >> (FIXEDPOINT / 2));
                clipint(&midint);
                lowint += (midint * (freint >> (FIXEDPOINT / 2)) >> (FIXEDPOINT / 2));
                clipint(&lowint);
            }
            for (i = 0; i <= LengthTable[waves]; i++) {
                // high = a0[i] - mid - low;
                // clip(&high);
                // mid += high * fre;
                // clip(&mid);
                // low += mid * fre;
                // clip(&low);
                // *Low++  = (char)low;
                // *High++ = (char)high;
 
                highint = (((int)(a0[i])) << FIXEDPOINT) - midint - lowint;
                clipint(&highint);
                midint += (highint * (freint >> (FIXEDPOINT / 2)) >> (FIXEDPOINT / 2));
                clipint(&midint);
                lowint += (midint * (freint >> (FIXEDPOINT / 2)) >> (FIXEDPOINT / 2));
                clipint(&lowint);
 
                char low_  = (lowint >> FIXEDPOINT);
                char high_ = (highint >> FIXEDPOINT);
 
                *Low++  = low_;
                *High++ = high_;
            }
            a0 += LengthTable[waves] + 1;
            // printf("start = %d, a0 = %d\n", start, a0);
        }
    }
}
 
int AHXOutput_SetOption(int Option, int Value)
{
 
    switch (Option) {
        case AHXOF_BOOST: {
            // Initialize volume table
            for (int i = 0; i < 65; i++) {
                for (int j = -128; j < 128; j++) {
                    VolumeTable[i][j + 128] = (int)(i * j * Value) / 64;
                }
            }
            Boost = Value;
        }
            return 1;
        default:
            return 0;
    }
}
 
void AHXPlayer_Init()
{
    Waves          = (struct AHXWaves *)malloc(sizeof(struct AHXWaves));
    WaveformTab[0] = Waves->Triangle04;
    WaveformTab[1] = Waves->Sawtooth04;
    WaveformTab[3] = Waves->WhiteNoiseBig;
 
    GenerateSawtooth(Waves->Sawtooth04, 0x04);
    GenerateSawtooth(Waves->Sawtooth08, 0x08);
    GenerateSawtooth(Waves->Sawtooth10, 0x10);
    GenerateSawtooth(Waves->Sawtooth20, 0x20);
    GenerateSawtooth(Waves->Sawtooth40, 0x40);
    GenerateSawtooth(Waves->Sawtooth80, 0x80);
    GenerateTriangle(Waves->Triangle04, 0x04);
    GenerateTriangle(Waves->Triangle08, 0x08);
    GenerateTriangle(Waves->Triangle10, 0x10);
    GenerateTriangle(Waves->Triangle20, 0x20);
    GenerateTriangle(Waves->Triangle40, 0x40);
    GenerateTriangle(Waves->Triangle80, 0x80);
    GenerateSquare(Waves->Squares);
    GenerateWhiteNoise(Waves->WhiteNoiseBig, 0x280 * 3);
    GenerateFilterWaveforms(Waves->Triangle04, Waves->LowPasses, Waves->HighPasses);
 
    MixingBuffer = (int *)malloc(sizeof(int) * (MixLen * Frequency / Hz));
 
    AHXOutput_SetOption(AHXOF_BOOST, Boost + 1);
}
 
void AHXPlayer_FreeMem()
{
    int i;
    // free old mem in reverse order
    // printf("1 Memory Allocated. %d bytes left.\n", QueryTotalFreeMemSize());
    for (i = 1; i < Song.InstrumentNr + 1; i++) {
        free(Instruments[i].PList.Entries);
        free(Instruments[i].Name);
    }
    free(Instruments);
 
    for (i = 0; i < Song.TrackNr + 1; i++) {
        free(Tracks[i]);
    }
    free(Tracks);
    free(Positions);
    free(Song.Subsongs);
    free(Song.Name);
    // printf("2 Memory Allocated. %d bytes left.\n", QueryTotalFreeMemSize());
}
 
int AHXPlayer_LoadSongBuffer(void *Buffer, int Len)
{
    int SongLength = Len;
    int i, j, MaxTrack;
    unsigned char *SongBuffer = (unsigned char *)Buffer;
    unsigned char *SBPtr      = &SongBuffer[14];
    char *NamePtr;
 
    AHXPlayer_FreeMem();
 
    if (SongLength < 14 || SongLength == 65536)
        return 0;
 
    if (SongBuffer[0] != 'T' && SongBuffer[1] != 'H' && SongBuffer[2] != 'X')
        return 0;
    Song.Revision = SongBuffer[3];
    if (Song.Revision > 1)
        return 0;
 
    // Header ////////////////////////////////////////////
    // Songname
    NamePtr   = (char *)&SongBuffer[(SongBuffer[4] << 8) | SongBuffer[5]];
    Song.Name = (char *)malloc(strlen(NamePtr) + 1);
    strcpy(Song.Name, NamePtr);
    NamePtr += strlen(NamePtr) + 1;
    Song.SpeedMultiplier = ((SongBuffer[6] >> 5) & 3) + 1;
 
    Song.PositionNr   = ((SongBuffer[6] & 0xf) << 8) | SongBuffer[7];
    Song.Restart      = (SongBuffer[8] << 8) | SongBuffer[9];
    Song.TrackLength  = SongBuffer[10];
    Song.TrackNr      = SongBuffer[11];
    Song.InstrumentNr = SongBuffer[12];
    Song.SubsongNr    = SongBuffer[13];
 
    // Subsongs //////////////////////////////////////////
    Song.Subsongs = (int *)malloc(sizeof(int) * Song.SubsongNr);
#ifndef COMPACT_CODE
    printf("name length = %d\n", strlen(NamePtr) + 1);
    printf("playing: %s\n", NamePtr);
    printf("subsongs = %d\n", Song.SubsongNr);
    printf("Positions = %d\n", Song.PositionNr);
    printf("Tracks = %d\n", (MaxTrack + 1));
#endif
    for (i = 0; i < Song.SubsongNr; i++) {
        if (SBPtr - SongBuffer > SongLength)
            return 0;
        Song.Subsongs[i] = (SBPtr[0] << 8) | SBPtr[1];
        SBPtr += 2;
    }
 
    // Position List /////////////////////////////////////
    Positions = (struct AHXPosition *)malloc(sizeof(struct AHXPosition) * Song.PositionNr);
    for (i = 0; i < Song.PositionNr; i++) {
        for (j = 0; j < 4; j++) {
            if (SBPtr - SongBuffer > SongLength)
                return 0;
            Positions[i].Track[j]     = *SBPtr++;
            Positions[i].Transpose[j] = *(signed char *)SBPtr++;
        }
    }
 
    // Tracks ////////////////////////////////////////////
    MaxTrack = Song.TrackNr;
    Tracks   = (struct AHXStep **)malloc(sizeof(struct AHXStep) * (MaxTrack + 1));
    for (i = 0; i < MaxTrack + 1; i++) {
        Tracks[i] = (struct AHXStep *)malloc(sizeof(struct AHXStep) * Song.TrackLength);
        if ((SongBuffer[6] & 0x80) == 0x80 && i == 0) {
            memset(Tracks[i], 0, Song.TrackLength * sizeof(struct AHXStep));
            continue;
        }
        for (j = 0; j < Song.TrackLength; j++) {
            if (SBPtr - SongBuffer > SongLength)
                return 0;
            Tracks[i][j].Note       = (SBPtr[0] >> 2) & 0x3f;
            Tracks[i][j].Instrument = ((SBPtr[0] & 0x3) << 4) | (SBPtr[1] >> 4);
            Tracks[i][j].FX         = SBPtr[1] & 0xf;
            Tracks[i][j].FXParam    = SBPtr[2];
            SBPtr += 3;
        }
    }
 
    // Instruments ///////////////////////////////////////
    Instruments = (struct AHXInstrument *)malloc(sizeof(struct AHXInstrument) * (Song.InstrumentNr + 1));
    for (i = 1; i < Song.InstrumentNr + 1; i++) {
        Instruments[i].Name = (char *)malloc(strlen(NamePtr) + 1);
        strcpy(Instruments[i].Name, NamePtr);
        NamePtr += strlen(NamePtr) + 1;
        if (SBPtr - SongBuffer > SongLength)
            return 0;
        Instruments[i].Volume               = SBPtr[0];
        Instruments[i].FilterSpeed          = ((SBPtr[1] >> 3) & 0x1f) | ((SBPtr[12] >> 2) & 0x20);
        Instruments[i].WaveLength           = SBPtr[1] & 0x7;
        Instruments[i].Envelope.aFrames     = SBPtr[2];
        Instruments[i].Envelope.aVolume     = SBPtr[3];
        Instruments[i].Envelope.dFrames     = SBPtr[4]; // 4
        Instruments[i].Envelope.dVolume     = SBPtr[5];
        Instruments[i].Envelope.sFrames     = SBPtr[6];
        Instruments[i].Envelope.rFrames     = SBPtr[7]; // 7
        Instruments[i].Envelope.rVolume     = SBPtr[8];
        Instruments[i].FilterLowerLimit     = SBPtr[12] & 0x7f;
        Instruments[i].VibratoDelay         = SBPtr[13]; // 13
        Instruments[i].HardCutReleaseFrames = (SBPtr[14] >> 4) & 7;
        Instruments[i].HardCutRelease       = SBPtr[14] & 0x80 ? 1 : 0;
        Instruments[i].VibratoDepth         = SBPtr[14] & 0xf; // 14
        Instruments[i].VibratoSpeed         = SBPtr[15];
        Instruments[i].SquareLowerLimit     = SBPtr[16];
        Instruments[i].SquareUpperLimit     = SBPtr[17]; // 17
        Instruments[i].SquareSpeed          = SBPtr[18];
        Instruments[i].FilterUpperLimit     = SBPtr[19] & 0x3f; // 19
        Instruments[i].PList.Speed          = SBPtr[20];
        Instruments[i].PList.Length         = SBPtr[21];
        SBPtr += 22;
        Instruments[i].PList.Entries = (struct AHXPListEntry *)malloc(sizeof(struct AHXPListEntry) * Instruments[i].PList.Length);
        for (j = 0; j < Instruments[i].PList.Length; j++) {
            if (SBPtr - SongBuffer > SongLength)
                return 0;
            Instruments[i].PList.Entries[j].FX[1]      = (SBPtr[0] >> 5) & 7;
            Instruments[i].PList.Entries[j].FX[0]      = (SBPtr[0] >> 2) & 7;
            Instruments[i].PList.Entries[j].Waveform   = ((SBPtr[0] << 1) & 6) | (SBPtr[1] >> 7);
            Instruments[i].PList.Entries[j].Fixed      = (SBPtr[1] >> 6) & 1;
            Instruments[i].PList.Entries[j].Note       = SBPtr[1] & 0x3f;
            Instruments[i].PList.Entries[j].FXParam[0] = SBPtr[2];
            Instruments[i].PList.Entries[j].FXParam[1] = SBPtr[3];
            SBPtr += 4;
        }
    }
    return Song.SubsongNr;
}
 
#ifdef WIN32
int AHXPlayer_LoadSong(char *Filename)
{
    int SongLength;
    FILE *f;
    unsigned char SongBuffer[65536];
    f = fopen(Filename, "rb");
    if (!f)
        return 0;
    SongLength = fread(SongBuffer, 1, 65536, f);
    fclose(f);
    return AHXPlayer_LoadSongBuffer(SongBuffer, SongLength);
}
#endif
 
int AHXPlayer_InitSubsong(int Nr)
{
    int v;
 
    if (Nr > Song.SubsongNr)
        return 0;
 
    if (Nr == 0)
        PosNr = 0;
    else
        PosNr = Song.Subsongs[Nr - 1];
 
    PosJump      = 0;
    PatternBreak = 0;
    MainVolume   = 0x40;
    Playing      = 1;
    NoteNr = PosJumpNote = 0;
    Tempo                = 6;
    StepWaitFrames       = 0;
    GetNewPosition       = 1;
    SongEndReached       = 0;
    TimingValue = PlayingTime = 0;
 
    for (v = 0; v < 4; v++) {
        AHXVoice_Init(&Voices[v]);
    }
 
    return 1;
}
 
void AHXPlayer_NextPosition()
{
    PosNr++;
    if (PosNr == Song.PositionNr)
        PosNr = 0;
    StepWaitFrames = 0;
    GetNewPosition = 1;
}
 
void AHXPlayer_PrevPosition()
{
    PosNr--;
    if (PosNr < 0)
        PosNr = 0;
    StepWaitFrames = 0;
    GetNewPosition = 1;
}
 
void AHXPlayer_ProcessStep(int v)
{
    int Note, Instrument, FX, FXParam, SquareLower, SquareUpper, d3, d4, d6, Neue, Alte, i;
 
    if (!Voices[v].TrackOn)
        return;
    Voices[v].VolumeSlideUp = Voices[v].VolumeSlideDown = 0;
 
    Note       = Tracks[Positions[PosNr].Track[v]][NoteNr].Note;
    Instrument = Tracks[Positions[PosNr].Track[v]][NoteNr].Instrument;
    FX         = Tracks[Positions[PosNr].Track[v]][NoteNr].FX;
    FXParam    = Tracks[Positions[PosNr].Track[v]][NoteNr].FXParam;
 
    switch (FX) {
        case 0x0: // Position Jump HI
            if ((FXParam & 0xf) > 0 && (FXParam & 0xf) <= 9)
                PosJump = FXParam & 0xf;
            break;
        case 0x5: // Volume Slide + Tone Portamento
        case 0xa: // Volume Slide
            Voices[v].VolumeSlideDown = FXParam & 0x0f;
            Voices[v].VolumeSlideUp   = FXParam >> 4;
            break;
        case 0xb: // Position Jump
            PosJump      = PosJump * 100 + (FXParam & 0x0f) + (FXParam >> 4) * 10;
            PatternBreak = 1;
            break;
        case 0xd: // Patternbreak
            PosJump     = PosNr + 1;
            PosJumpNote = (FXParam & 0x0f) + (FXParam >> 4) * 10;
            if (PosJumpNote > Song.TrackLength)
                PosJumpNote = 0;
            PatternBreak = 1;
            break;
        case 0xe: // Enhanced commands
            switch (FXParam >> 4) {
                case 0xc: // Note Cut
                    if ((FXParam & 0x0f) < Tempo) {
                        Voices[v].NoteCutWait = FXParam & 0x0f;
                        if (Voices[v].NoteCutWait) {
                            Voices[v].NoteCutOn      = 1;
                            Voices[v].HardCutRelease = 0;
                        }
                    }
                    break;
                case 0xd: // Note Delay
                    if (Voices[v].NoteDelayOn) {
                        Voices[v].NoteDelayOn = 0;
                    } else {
                        if ((FXParam & 0x0f) < Tempo) {
                            Voices[v].NoteDelayWait = FXParam & 0x0f;
                            if (Voices[v].NoteDelayWait) {
                                Voices[v].NoteDelayOn = 1;
                                return;
                            }
                        }
                    }
                    break;
            }
            break;
        case 0xf: // Speed
            Tempo = FXParam;
            break;
    }
    if (Instrument) {
        Voices[v].PerfSubVolume    = 0x40;
        Voices[v].PeriodSlideSpeed = Voices[v].PeriodSlidePeriod = Voices[v].PeriodSlideLimit = 0;
        Voices[v].ADSRVolume                                                                  = 0;
        Voices[v].Instrument                                                                  = &Instruments[Instrument];
        AHXVoice_CalcADSR(&Voices[v]);
        // InitOnInstrument
        Voices[v].WaveLength    = Voices[v].Instrument->WaveLength;
        Voices[v].NoteMaxVolume = Voices[v].Instrument->Volume;
        // InitVibrato
        Voices[v].VibratoCurrent = 0;
        Voices[v].VibratoDelay   = Voices[v].Instrument->VibratoDelay;
        Voices[v].VibratoDepth   = Voices[v].Instrument->VibratoDepth;
        Voices[v].VibratoSpeed   = Voices[v].Instrument->VibratoSpeed;
        Voices[v].VibratoPeriod  = 0;
        // InitHardCut
        Voices[v].HardCutRelease = Voices[v].Instrument->HardCutRelease;
        Voices[v].HardCut        = Voices[v].Instrument->HardCutReleaseFrames;
        // InitSquare
        Voices[v].IgnoreSquare = Voices[v].SquareSlidingIn = 0;
        Voices[v].SquareWait = Voices[v].SquareOn = 0;
        SquareLower                               = Voices[v].Instrument->SquareLowerLimit >> (5 - Voices[v].WaveLength);
        SquareUpper                               = Voices[v].Instrument->SquareUpperLimit >> (5 - Voices[v].WaveLength);
        if (SquareUpper < SquareLower) {
            int t       = SquareUpper;
            SquareUpper = SquareLower;
            SquareLower = t;
        }
        Voices[v].SquareUpperLimit = SquareUpper;
        Voices[v].SquareLowerLimit = SquareLower;
        // InitFilter
        Voices[v].IgnoreFilter = Voices[v].FilterWait = Voices[v].FilterOn = 0;
        Voices[v].FilterSlidingIn                                          = 0;
        d6                                                                 = Voices[v].Instrument->FilterSpeed;
        d3                                                                 = Voices[v].Instrument->FilterLowerLimit;
        d4                                                                 = Voices[v].Instrument->FilterUpperLimit;
        if (d3 & 0x80)
            d6 |= 0x20;
        if (d4 & 0x80)
            d6 |= 0x40;
        Voices[v].FilterSpeed = d6;
        d3 &= ~0x80;
        d4 &= ~0x80;
        if (d3 > d4) {
            int t = d3;
            d3    = d4;
            d4    = t;
        }
        Voices[v].FilterUpperLimit = d4;
        Voices[v].FilterLowerLimit = d3;
        Voices[v].FilterPos        = 32;
        // Init PerfList
        Voices[v].PerfWait = Voices[v].PerfCurrent = 0;
        Voices[v].PerfSpeed                        = Voices[v].Instrument->PList.Speed;
        Voices[v].PerfList                         = &Voices[v].Instrument->PList;
    }
    // NoInstrument
    Voices[v].PeriodSlideOn = 0;
 
    switch (FX) {
        case 0x4: // Override filter
            break;
        case 0x9: // Set Squarewave-Offset
            Voices[v].SquarePos    = FXParam >> (5 - Voices[v].WaveLength);
            Voices[v].PlantSquare  = 1;
            Voices[v].IgnoreSquare = 1;
            break;
        case 0x5: // Tone Portamento + Volume Slide
        case 0x3: // Tone Portamento (Period Slide Up/Down w/ Limit)
            if (FXParam != 0)
                Voices[v].PeriodSlideSpeed = FXParam;
            if (Note) {
                Neue = PeriodTable[Note];
                Alte = PeriodTable[Voices[v].TrackPeriod];
                Alte -= Neue;
                Neue = Alte + Voices[v].PeriodSlidePeriod;
                if (Neue)
                    Voices[v].PeriodSlideLimit = -Alte;
            }
            Voices[v].PeriodSlideOn        = 1;
            Voices[v].PeriodSlideWithLimit = 1;
            goto NoNote;
    }
 
    // Note anschlagen
    if (Note) {
        Voices[v].TrackPeriod = Note;
        Voices[v].PlantPeriod = 1;
    }
NoNote:
    switch (FX) {
        case 0x1: // Portamento up (Period slide down)
            Voices[v].PeriodSlideSpeed     = -FXParam;
            Voices[v].PeriodSlideOn        = 1;
            Voices[v].PeriodSlideWithLimit = 0;
            break;
        case 0x2: // Portamento down (Period slide up)
            Voices[v].PeriodSlideSpeed     = FXParam;
            Voices[v].PeriodSlideOn        = 1;
            Voices[v].PeriodSlideWithLimit = 0;
            break;
        case 0xc: // Volume
            if (FXParam <= 0x40)
                Voices[v].NoteMaxVolume = FXParam;
            else {
                FXParam -= 0x50;
                if (FXParam <= 0x40)
                    for (i = 0; i < 4; i++)
                        Voices[i].TrackMasterVolume = FXParam;
                else {
                    FXParam -= 0xa0 - 0x50;
                    if (FXParam <= 0x40)
                        Voices[v].TrackMasterVolume = FXParam;
                }
            }
            break;
        case 0xe: // Enhanced commands
            switch (FXParam >> 4) {
                case 0x1: // Fineslide up (Period fineslide down)
                    Voices[v].PeriodSlidePeriod = -(FXParam & 0x0f);
                    Voices[v].PlantPeriod       = 1;
                    break;
                case 0x2: // Fineslide down (Period fineslide up)
                    Voices[v].PeriodSlidePeriod = FXParam & 0x0f;
                    Voices[v].PlantPeriod       = 1;
                    break;
                case 0x4: // Vibrato control
                    Voices[v].VibratoDepth = FXParam & 0x0f;
                    break;
                case 0xa: // Finevolume up
                    Voices[v].NoteMaxVolume += FXParam & 0x0f;
                    if (Voices[v].NoteMaxVolume > 0x40)
                        Voices[v].NoteMaxVolume = 0x40;
                    break;
                case 0xb: // Finevolume down
                    Voices[v].NoteMaxVolume -= FXParam & 0x0f;
                    if (Voices[v].NoteMaxVolume < 0)
                        Voices[v].NoteMaxVolume = 0;
                    break;
            }
            break;
    }
}
 
void AHXPlayer_PListCommandParse(int v, int FX, int FXParam)
{
    switch (FX) {
        case 0:
            if (Song.Revision > 0 && FXParam != 0) {
                if (Voices[v].IgnoreFilter) {
                    Voices[v].FilterPos    = Voices[v].IgnoreFilter;
                    Voices[v].IgnoreFilter = 0;
                } else
                    Voices[v].FilterPos = FXParam;
                Voices[v].NewWaveform = 1;
            }
            break;
        case 1:
            Voices[v].PeriodPerfSlideSpeed = FXParam;
            Voices[v].PeriodPerfSlideOn    = 1;
            break;
        case 2:
            Voices[v].PeriodPerfSlideSpeed = -FXParam;
            Voices[v].PeriodPerfSlideOn    = 1;
            break;
        case 3: // Init Square Modulation
            if (!Voices[v].IgnoreSquare) {
                Voices[v].SquarePos = FXParam >> (5 - Voices[v].WaveLength);
            } else
                Voices[v].IgnoreSquare = 0;
            break;
        case 4: // Start/Stop Modulation
            if (Song.Revision == 0 || FXParam == 0) {
                Voices[v].SquareInit = (Voices[v].SquareOn ^= 1);
                Voices[v].SquareSign = 1;
            } else {
                if (FXParam & 0x0f) {
                    Voices[v].SquareInit = (Voices[v].SquareOn ^= 1);
                    Voices[v].SquareSign = 1;
                    if ((FXParam & 0x0f) == 0x0f)
                        Voices[v].SquareSign = -1;
                }
                if (FXParam & 0xf0) {
                    Voices[v].FilterInit = (Voices[v].FilterOn ^= 1);
                    Voices[v].FilterSign = 1;
                    if ((FXParam & 0xf0) == 0xf0)
                        Voices[v].FilterSign = -1;
                }
            }
            break;
        case 5: // Jump to Step [xx]
            Voices[v].PerfCurrent = FXParam;
            break;
        case 6: // Set Volume
            if (FXParam > 0x40) {
                if ((FXParam -= 0x50) >= 0) {
                    if (FXParam <= 0x40)
                        Voices[v].PerfSubVolume = FXParam;
                    else if ((FXParam -= 0xa0 - 0x50) >= 0)
                        if (FXParam <= 0x40)
                            Voices[v].TrackMasterVolume = FXParam;
                }
            } else
                Voices[v].NoteMaxVolume = FXParam;
            break;
        case 7: // set speed
            Voices[v].PerfSpeed = Voices[v].PerfWait = FXParam;
            break;
    }
}
 
void AHXPlayer_ProcessFrame(int v)
{
    int i;
    char *AudioSource;
 
    if (!Voices[v].TrackOn)
        return;
 
    if (Voices[v].NoteDelayOn) {
        if (Voices[v].NoteDelayWait <= 0)
            AHXPlayer_ProcessStep(v);
        else
            Voices[v].NoteDelayWait--;
    }
    if (Voices[v].HardCut) {
        int NextInstrument;
        if (NoteNr + 1 < Song.TrackLength)
            NextInstrument = Tracks[Voices[v].Track][NoteNr + 1].Instrument;
        else
            NextInstrument = Tracks[Voices[v].NextTrack][0].Instrument;
        if (NextInstrument) {
            int d1 = Tempo - Voices[v].HardCut;
            if (d1 < 0)
                d1 = 0;
            if (!Voices[v].NoteCutOn) {
                Voices[v].NoteCutOn       = 1;
                Voices[v].NoteCutWait     = d1;
                Voices[v].HardCutReleaseF = -(d1 - Tempo);
            } else
                Voices[v].HardCut = 0;
        }
    }
    if (Voices[v].NoteCutOn) {
        if (Voices[v].NoteCutWait <= 0) {
            Voices[v].NoteCutOn = 0;
            if (Voices[v].HardCutRelease) {
                Voices[v].ADSR.rVolume = -(Voices[v].ADSRVolume - (Voices[v].Instrument->Envelope.rVolume << 8)) / Voices[v].HardCutReleaseF;
                Voices[v].ADSR.rFrames = Voices[v].HardCutReleaseF;
                Voices[v].ADSR.aFrames = Voices[v].ADSR.dFrames = Voices[v].ADSR.sFrames = 0;
            } else
                Voices[v].NoteMaxVolume = 0;
        } else
            Voices[v].NoteCutWait--;
    }
    // adsrEnvelope
    if (Voices[v].ADSR.aFrames) {
        Voices[v].ADSRVolume += Voices[v].ADSR.aVolume; // Delta
        if (--Voices[v].ADSR.aFrames <= 0)
            Voices[v].ADSRVolume = Voices[v].Instrument->Envelope.aVolume << 8;
    } else if (Voices[v].ADSR.dFrames) {
        Voices[v].ADSRVolume += Voices[v].ADSR.dVolume; // Delta
        if (--Voices[v].ADSR.dFrames <= 0)
            Voices[v].ADSRVolume = Voices[v].Instrument->Envelope.dVolume << 8;
    } else if (Voices[v].ADSR.sFrames) {
        Voices[v].ADSR.sFrames--;
    } else if (Voices[v].ADSR.rFrames) {
        Voices[v].ADSRVolume += Voices[v].ADSR.rVolume; // Delta
        if (--Voices[v].ADSR.rFrames <= 0)
            Voices[v].ADSRVolume = Voices[v].Instrument->Envelope.rVolume << 8;
    }
    // VolumeSlide
    Voices[v].NoteMaxVolume = Voices[v].NoteMaxVolume + Voices[v].VolumeSlideUp - Voices[v].VolumeSlideDown;
    if (Voices[v].NoteMaxVolume < 0)
        Voices[v].NoteMaxVolume = 0;
    if (Voices[v].NoteMaxVolume > 0x40)
        Voices[v].NoteMaxVolume = 0x40;
    // Portamento
    if (Voices[v].PeriodSlideOn) {
        if (Voices[v].PeriodSlideWithLimit) {
            int d0 = Voices[v].PeriodSlidePeriod - Voices[v].PeriodSlideLimit;
            int d2 = Voices[v].PeriodSlideSpeed;
            if (d0 > 0)
                d2 = -d2;
            if (d0) {
                int d3 = (d0 + d2) ^ d0;
                if (d3 >= 0)
                    d0 = Voices[v].PeriodSlidePeriod + d2;
                else
                    d0 = Voices[v].PeriodSlideLimit;
                Voices[v].PeriodSlidePeriod = d0;
                Voices[v].PlantPeriod       = 1;
            }
        } else {
            Voices[v].PeriodSlidePeriod += Voices[v].PeriodSlideSpeed;
            Voices[v].PlantPeriod = 1;
        }
    }
    // Vibrato
    if (Voices[v].VibratoDepth) {
        if (Voices[v].VibratoDelay <= 0) {
            Voices[v].VibratoPeriod  = (VibratoTable[Voices[v].VibratoCurrent] * Voices[v].VibratoDepth) >> 7;
            Voices[v].PlantPeriod    = 1;
            Voices[v].VibratoCurrent = (Voices[v].VibratoCurrent + Voices[v].VibratoSpeed) & 0x3f;
        } else
            Voices[v].VibratoDelay--;
    }
    // PList
    if (Voices[v].Instrument && Voices[v].PerfCurrent < Voices[v].Instrument->PList.Length) {
        if (--Voices[v].PerfWait <= 0) {
            int Cur            = Voices[v].PerfCurrent++;
            Voices[v].PerfWait = Voices[v].PerfSpeed;
            if (Voices[v].PerfList->Entries[Cur].Waveform) {
                Voices[v].Waveform             = Voices[v].PerfList->Entries[Cur].Waveform - 1;
                Voices[v].NewWaveform          = 1;
                Voices[v].PeriodPerfSlideSpeed = Voices[v].PeriodPerfSlidePeriod = 0;
            }
            // Holdwave
            Voices[v].PeriodPerfSlideOn = 0;
            for (i = 0; i < 2; i++)
                AHXPlayer_PListCommandParse(v, Voices[v].PerfList->Entries[Cur].FX[i], Voices[v].PerfList->Entries[Cur].FXParam[i]);
            // GetNote
            if (Voices[v].PerfList->Entries[Cur].Note) {
                Voices[v].InstrPeriod = Voices[v].PerfList->Entries[Cur].Note;
                Voices[v].PlantPeriod = 1;
                Voices[v].FixedNote   = Voices[v].PerfList->Entries[Cur].Fixed;
            }
        }
    } else {
        if (Voices[v].PerfWait)
            Voices[v].PerfWait--;
        else
            Voices[v].PeriodPerfSlideSpeed = 0;
    }
    // PerfPortamento
    if (Voices[v].PeriodPerfSlideOn) {
        Voices[v].PeriodPerfSlidePeriod -= Voices[v].PeriodPerfSlideSpeed;
        if (Voices[v].PeriodPerfSlidePeriod)
            Voices[v].PlantPeriod = 1;
    }
    if (Voices[v].Waveform == 3 - 1 && Voices[v].SquareOn) {
        if (--Voices[v].SquareWait <= 0) {
            int d1 = Voices[v].SquareLowerLimit;
            int d2 = Voices[v].SquareUpperLimit;
            int d3 = Voices[v].SquarePos;
            if (Voices[v].SquareInit) {
                Voices[v].SquareInit = 0;
                if (d3 <= d1) {
                    Voices[v].SquareSlidingIn = 1;
                    Voices[v].SquareSign      = 1;
                } else if (d3 >= d2) {
                    Voices[v].SquareSlidingIn = 1;
                    Voices[v].SquareSign      = -1;
                }
            }
            // NoSquareInit
            if (d1 == d3 || d2 == d3) {
                if (Voices[v].SquareSlidingIn) {
                    Voices[v].SquareSlidingIn = 0;
                } else {
                    Voices[v].SquareSign = -Voices[v].SquareSign;
                }
            }
            d3 += Voices[v].SquareSign;
            Voices[v].SquarePos   = d3;
            Voices[v].PlantSquare = 1;
            Voices[v].SquareWait  = Voices[v].Instrument->SquareSpeed;
        }
    }
    if (Voices[v].FilterOn && --Voices[v].FilterWait <= 0) {
        int d1 = Voices[v].FilterLowerLimit;
        int d2 = Voices[v].FilterUpperLimit;
        int d3 = Voices[v].FilterPos;
        if (Voices[v].FilterInit) {
            Voices[v].FilterInit = 0;
            if (d3 <= d1) {
                Voices[v].FilterSlidingIn = 1;
                Voices[v].FilterSign      = 1;
            } else if (d3 >= d2) {
                Voices[v].FilterSlidingIn = 1;
                Voices[v].FilterSign      = -1;
            }
        }
        // NoFilterInit
        int FMax = (Voices[v].FilterSpeed < 3) ? (5 - Voices[v].FilterSpeed) : 1;
        for (i = 0; i < FMax; i++) {
            if (d1 == d3 || d2 == d3) {
                if (Voices[v].FilterSlidingIn) {
                    Voices[v].FilterSlidingIn = 0;
                } else {
                    Voices[v].FilterSign = -Voices[v].FilterSign;
                }
            }
            d3 += Voices[v].FilterSign;
        }
        Voices[v].FilterPos   = d3;
        Voices[v].NewWaveform = 1;
        Voices[v].FilterWait  = Voices[v].FilterSpeed - 3;
        if (Voices[v].FilterWait < 1)
            Voices[v].FilterWait = 1;
    }
    if (Voices[v].Waveform == 3 - 1 || Voices[v].PlantSquare) {
        char *SquarePtr;
 
        // CalcSquare
        SquarePtr = &Waves->Squares[(Voices[v].FilterPos - 0x20) * (0xfc + 0xfc + 0x80 * 0x1f + 0x80 + 0x280 * 3)];
        int X     = Voices[v].SquarePos << (5 - Voices[v].WaveLength);
        if (X > 0x20) {
            X                       = 0x40 - X;
            Voices[v].SquareReverse = 1;
        }
        // OkDownSquare
        if (--X)
            SquarePtr += X << 7;
        int Delta      = 32 >> Voices[v].WaveLength;
        WaveformTab[2] = Voices[v].SquareTempBuffer;
        for (i = 0; i < (1 << Voices[v].WaveLength) * 4; i++) {
            Voices[v].SquareTempBuffer[i] = *SquarePtr;
            SquarePtr += Delta;
        }
        Voices[v].NewWaveform = 1;
        Voices[v].Waveform    = 3 - 1;
        Voices[v].PlantSquare = 0;
    }
    if (Voices[v].Waveform == 4 - 1)
        Voices[v].NewWaveform = 1;
 
    if (Voices[v].NewWaveform) {
        AudioSource = WaveformTab[Voices[v].Waveform];
        if (Voices[v].Waveform != 3 - 1) {
            AudioSource += (Voices[v].FilterPos - 0x20) * (0xfc + 0xfc + 0x80 * 0x1f + 0x80 + 0x280 * 3);
        }
        if (Voices[v].Waveform < 3 - 1) {
            AudioSource += Offsets[Voices[v].WaveLength];
        }
        if (Voices[v].Waveform == 4 - 1) {
            // AddRandomMoving
            AudioSource += (WNRandom & (2 * 0x280 - 1)) & ~1;
            // GoOnRandom
            WNRandom += 2239384;
            WNRandom = ((((WNRandom >> 8) | (WNRandom << 24)) + 782323) ^ 75) - 6735;
        }
        Voices[v].AudioSource = AudioSource;
    }
    // StillHoldWaveform
    // AudioInitPeriod
    Voices[v].AudioPeriod = Voices[v].InstrPeriod;
    if (!Voices[v].FixedNote)
        Voices[v].AudioPeriod += Voices[v].Transpose + Voices[v].TrackPeriod - 1;
    if (Voices[v].AudioPeriod > 5 * 12)
        Voices[v].AudioPeriod = 5 * 12;
    if (Voices[v].AudioPeriod < 0)
        Voices[v].AudioPeriod = 0;
    Voices[v].AudioPeriod = PeriodTable[Voices[v].AudioPeriod];
    if (!Voices[v].FixedNote)
        Voices[v].AudioPeriod += Voices[v].PeriodSlidePeriod;
    Voices[v].AudioPeriod += Voices[v].PeriodPerfSlidePeriod + Voices[v].VibratoPeriod;
    if (Voices[v].AudioPeriod > 0x0d60)
        Voices[v].AudioPeriod = 0x0d60;
    if (Voices[v].AudioPeriod < 0x0071)
        Voices[v].AudioPeriod = 0x0071;
    // AudioInitVolume
    Voices[v].AudioVolume = ((((((((Voices[v].ADSRVolume >> 8) * Voices[v].NoteMaxVolume) >> 6) * Voices[v].PerfSubVolume) >> 6) * Voices[v].TrackMasterVolume) >> 6) * MainVolume) >> 6;
}
 
void AHXPlayer_SetAudio(int v)
{
    if (!Voices[v].TrackOn) {
        Voices[v].VoiceVolume = 0;
        return;
    }
 
    Voices[v].VoiceVolume = Voices[v].AudioVolume;
    if (Voices[v].PlantPeriod) {
        Voices[v].PlantPeriod = 0;
        Voices[v].VoicePeriod = Voices[v].AudioPeriod;
    }
    if (Voices[v].NewWaveform) {
        if (Voices[v].Waveform == 4 - 1) {
            memcpy(Voices[v].VoiceBuffer, Voices[v].AudioSource, 0x280);
        } else {
            int i, WaveLoops;
 
            WaveLoops = (1 << (5 - Voices[v].WaveLength)) * 5;
            for (i = 0; i < WaveLoops; i++)
                memcpy(&Voices[v].VoiceBuffer[i * 4 * (1 << Voices[v].WaveLength)], Voices[v].AudioSource, 4 * (1 << Voices[v].WaveLength));
        }
        Voices[v].VoiceBuffer[0x280] = Voices[v].VoiceBuffer[0];
    }
}
 
void AHXPlayer_VoiceOnOff(int Voice, int OnOff)
{
    if (Voice < 0 || Voice > 3)
        return;
    Voices[Voice].TrackOn = OnOff;
}
 
// AHXOutput ///////////////////////////////////////////////////////////////////////////////////////////////
 
 
void AHXPlayer_PlayIRQ()
{
    int i, a;
    if (StepWaitFrames <= 0) {
        if (GetNewPosition) {
            int NextPos;
 
            NextPos = (PosNr + 1 == Song.PositionNr) ? 0 : (PosNr + 1);
            for (i = 0; i < 4; i++) {
                Voices[i].Track         = Positions[PosNr].Track[i];
                Voices[i].Transpose     = Positions[PosNr].Transpose[i];
                Voices[i].NextTrack     = Positions[NextPos].Track[i];
                Voices[i].NextTranspose = Positions[NextPos].Transpose[i];
            }
            GetNewPosition = 0;
        }
        for (i = 0; i < 4; i++)
            AHXPlayer_ProcessStep(i);
        StepWaitFrames = Tempo;
    }
    // DoFrameStuff
    for (i = 0; i < 4; i++)
        AHXPlayer_ProcessFrame(i);
    PlayingTime++;
    if (Tempo > 0 && --StepWaitFrames <= 0) {
        if (!PatternBreak) {
            NoteNr++;
            if (NoteNr >= Song.TrackLength) {
                PosJump      = PosNr + 1;
                PosJumpNote  = 0;
                PatternBreak = 1;
            }
        }
        if (PatternBreak) {
            PatternBreak = 0;
            NoteNr       = PosJumpNote;
            PosJumpNote  = 0;
            PosNr        = PosJump;
            PosJump      = 0;
            if (PosNr == Song.PositionNr) {
                SongEndReached = 1;
                PosNr          = Song.Restart;
            }
            GetNewPosition = 1;
        }
    }
    // RemainPosition
    for (a = 0; a < 4; a++)
        AHXPlayer_SetAudio(a);
}
 
void AHXPlayer_SetBoost(int boostval)
{
    Boost = boostval;
    AHXOutput_SetOption(AHXOF_BOOST, Boost + 1);
}
 
void AHXPlayer_SetOversampling(int enable)
{
    Oversampling = enable;
}
 
void AHXOutput_MixChunk(int NrSamples, int **mb)
{
    int v, delta, samples_to_mix, mixpos, *VolTab, i, offset, sample1, sample2, frac1, frac2, thiscount;
    long freq;
 
    for (v = 0; v < 4; v++) {
        if (Voices[v].VoiceVolume == 0)
            continue;
        freq           = Period2Freq(Voices[v].VoicePeriod);
        delta          = (int)(freq * (1 << 16) / Frequency);
        samples_to_mix = NrSamples;
        mixpos         = 0;
        while (samples_to_mix) {
            if (pos[v] > (0x280 << 16))
                pos[v] -= 0x280 << 16;
            thiscount = min(samples_to_mix, ((0x280 << 16) - pos[v] - 1) / delta + 1);
            samples_to_mix -= thiscount;
            VolTab = &VolumeTable[Voices[v].VoiceVolume][128];
            // INNER LOOP
            if (Oversampling) {
                for (i = 0; i < thiscount; i++) {
                    offset  = pos[v] >> 16;
                    sample1 = VolTab[(int)Voices[v].VoiceBuffer[offset]];
                    sample2 = VolTab[(int)Voices[v].VoiceBuffer[offset + 1]];
                    frac1   = pos[v] & ((1 << 16) - 1);
                    frac2   = (1 << 16) - frac1;
                    (*mb)[mixpos++] += ((sample1 * frac2) + (sample2 * frac1)) >> 16;
                    pos[v] += delta;
                }
            } else {
                for (i = 0; i < thiscount; i++) {
                    (*mb)[mixpos++] += VolTab[(int)Voices[v].VoiceBuffer[pos[v] >> 16]];
                    pos[v] += delta;
                }
            }
        } // while
    }     // v = 0-3
    *mb += NrSamples;
}
 
void AHXOutput_MixBuffer(short *target)
{
#define LOW_CLIP16 -0x8000
#define HI_CLIP16  0x7FFF
#define LOW_CLIP8  -0x80
#define HI_CLIP8   0x7F
    int f;
    int NrSamples = Frequency / Hz / Song.SpeedMultiplier;
    int *mb       = MixingBuffer;
    int s;
 
    memset(MixingBuffer, 0, MixLen * Frequency / Hz * sizeof(int));
    for (f = 0; f < MixLen * Song.SpeedMultiplier /* MixLen = # frames */; f++) {
        AHXPlayer_PlayIRQ();
        AHXOutput_MixChunk(NrSamples, &mb);
    } // frames
 
    for (s = 0; s < BlockLen / (16 / 8); s++) {
        int thissample;
 
        thissample = *(MixingBuffer + s) << 6; // 16 bit
        target[s]  = thissample < LOW_CLIP16 ? LOW_CLIP16 : thissample > HI_CLIP16 ? HI_CLIP16 :
                                                                                     thissample;
    }
}