Gravis Ultrasound GF1 sound card emulation (malc).

git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@3921 c046a42c-6fe2-441c-8c8c-71466251a162

5 files changed, 1329 insertions, 0 deletions

diff --git a/hw/gus.c b/hw/gus.c
new file mode 100644
index 0000000000..57753a7f5c
--- /dev/null
+++ b/hw/gus.c
@@ -0,0 +1,300 @@
+/*
+ * QEMU Proxy for Gravis Ultrasound GF1 emulation by Tibor "TS" Schütz
+ *
+ * Copyright (c) 2002-2005 Vassili Karpov (malc)
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+#include "hw.h"
+#include "audiodev.h"
+#include "audio/audio.h"
+#include "isa.h"
+#include "gusemu.h"
+#include "gustate.h"
+
+#define dolog(...) AUD_log ("audio", __VA_ARGS__)
+#ifdef DEBUG
+#define ldebug(...) dolog (__VA_ARGS__)
+#else
+#define ldebug(...)
+#endif
+
+#ifdef WORDS_BIGENDIAN
+#define GUS_ENDIANNESS 1
+#else
+#define GUS_ENDIANNESS 0
+#endif
+
+#define IO_READ_PROTO(name) \
+    uint32_t name (void *opaque, uint32_t nport)
+#define IO_WRITE_PROTO(name) \
+    void name (void *opaque, uint32_t nport, uint32_t val)
+
+static struct {
+    int port;
+    int irq;
+    int dma;
+    int freq;
+} conf = {0x240, 7, 3, 44100};
+
+typedef struct GUSState {
+    GUSEmuState emu;
+    QEMUSoundCard card;
+    int freq;
+    int pos, left, shift, irqs;
+    uint16_t *mixbuf;
+    uint8_t himem[1024 * 1024 + 32 + 4096];
+    int samples;
+    SWVoiceOut *voice;
+    int64_t last_ticks;
+    qemu_irq *pic;
+} GUSState;
+
+IO_READ_PROTO (gus_readb)
+{
+    GUSState *s = opaque;
+
+    return gus_read (&s->emu, nport, 1);
+}
+
+IO_READ_PROTO (gus_readw)
+{
+    GUSState *s = opaque;
+
+    return gus_read (&s->emu, nport, 2);
+}
+
+IO_WRITE_PROTO (gus_writeb)
+{
+    GUSState *s = opaque;
+
+    gus_write (&s->emu, nport, 1, val);
+}
+
+IO_WRITE_PROTO (gus_writew)
+{
+    GUSState *s = opaque;
+
+    gus_write (&s->emu, nport, 2, val);
+}
+
+static int write_audio (GUSState *s, int samples)
+{
+    int net = 0;
+    int pos = s->pos;
+
+    while (samples) {
+        int nbytes, wbytes, wsampl;
+
+        nbytes = samples << s->shift;
+        wbytes = AUD_write (
+            s->voice,
+            s->mixbuf + (pos << (s->shift - 1)),
+            nbytes
+            );
+
+        if (wbytes) {
+            wsampl = wbytes >> s->shift;
+
+            samples -= wsampl;
+            pos = (pos + wsampl) % s->samples;
+
+            net += wsampl;
+        }
+        else {
+            break;
+        }
+    }
+
+    return net;
+}
+
+static void GUS_callback (void *opaque, int free)
+{
+    int samples, to_play, net = 0;
+    GUSState *s = opaque;
+
+    samples = free >> s->shift;
+    to_play = audio_MIN (samples, s->left);
+
+    while (to_play) {
+        int written = write_audio (s, to_play);
+
+        if (!written) {
+            goto reset;
+        }
+
+        s->left -= written;
+        to_play -= written;
+        samples -= written;
+        net += written;
+    }
+
+    samples = audio_MIN (samples, s->samples);
+    if (samples) {
+        gus_mixvoices (&s->emu, s->freq, samples, s->mixbuf);
+
+        while (samples) {
+            int written = write_audio (s, samples);
+            if (!written) {
+                break;
+            }
+            samples -= written;
+            net += written;
+        }
+    }
+    s->left = samples;
+
+reset:
+    gus_irqgen (&s->emu, (double) (net * 1000000) / s->freq);
+}
+
+int GUS_irqrequest (GUSEmuState *emu, int hwirq, int n)
+{
+    GUSState *s = emu->opaque;
+    /* qemu_irq_lower (s->pic[hwirq]); */
+    qemu_irq_raise (s->pic[hwirq]);
+    s->irqs += n;
+    ldebug ("irqrequest %d %d %d\n", hwirq, n, s->irqs);
+    return n;
+}
+
+void GUS_irqclear (GUSEmuState *emu, int hwirq)
+{
+    GUSState *s = emu->opaque;
+    ldebug ("irqclear %d %d\n", hwirq, s->irqs);
+    qemu_irq_lower (s->pic[hwirq]);
+    s->irqs -= 1;
+#ifdef IRQ_STORM
+    if (s->irqs > 0) {
+        qemu_irq_raise (s->pic[hwirq]);
+    }
+#endif
+}
+
+void GUS_dmarequest (GUSEmuState *der)
+{
+    /* GUSState *s = (GUSState *) der; */
+    ldebug ("dma request %d\n", der->gusdma);
+    DMA_hold_DREQ (der->gusdma);
+}
+
+int GUS_read_DMA (void *opaque, int nchan, int dma_pos, int dma_len)
+{
+    GUSState *s = opaque;
+    int8_t tmpbuf[4096];
+    int pos = dma_pos, mode, left = dma_len - dma_pos;
+
+    ldebug ("read DMA %#x %d\n", dma_pos, dma_len);
+    mode = DMA_get_channel_mode (s->emu.gusdma);
+    while (left) {
+        int to_copy = audio_MIN ((size_t) left, sizeof (tmpbuf));
+        int copied;
+
+        ldebug ("left=%d to_copy=%d pos=%d\n", left, to_copy, pos);
+        copied = DMA_read_memory (nchan, tmpbuf, pos, to_copy);
+        gus_dma_transferdata (&s->emu, tmpbuf, copied, left == copied);
+        left -= copied;
+        pos += copied;
+    }
+
+    if (0 == ((mode >> 4) & 1)) {
+        DMA_release_DREQ (s->emu.gusdma);
+    }
+    return dma_len;
+}
+
+int GUS_init (AudioState *audio, qemu_irq *pic)
+{
+    GUSState *s;
+    audsettings_t as;
+
+    if (!audio) {
+        dolog ("No audio state\n");
+        return -1;
+    }
+
+    s = qemu_mallocz (sizeof (*s));
+    if (!s) {
+        dolog ("Could not allocate memory for GUS (%zu bytes)\n",
+               sizeof (*s));
+        return -1;
+    }
+
+    AUD_register_card (audio, "gus", &s->card);
+
+    as.freq = conf.freq;
+    as.nchannels = 2;
+    as.fmt = AUD_FMT_S16;
+    as.endianness = GUS_ENDIANNESS;
+
+    s->voice = AUD_open_out (
+        &s->card,
+        NULL,
+        "gus",
+        s,
+        GUS_callback,
+        &as
+        );
+
+    if (!s->voice) {
+        AUD_remove_card (&s->card);
+        qemu_free (s);
+        return -1;
+    }
+
+    s->shift = 2;
+    s->samples = AUD_get_buffer_size_out (s->voice) >> s->shift;
+    s->mixbuf = qemu_mallocz (s->samples << s->shift);
+    if (!s->mixbuf) {
+        AUD_close_out (&s->card, s->voice);
+        AUD_remove_card (&s->card);
+        qemu_free (s);
+        return -1;
+    }
+
+    register_ioport_write (conf.port, 1, 1, gus_writeb, s);
+    register_ioport_write (conf.port, 1, 2, gus_writew, s);
+
+    register_ioport_read ((conf.port + 0x100) & 0xf00, 1, 1, gus_readb, s);
+    register_ioport_read ((conf.port + 0x100) & 0xf00, 1, 2, gus_readw, s);
+
+    register_ioport_write (conf.port + 6, 10, 1, gus_writeb, s);
+    register_ioport_write (conf.port + 6, 10, 2, gus_writew, s);
+    register_ioport_read (conf.port + 6, 10, 1, gus_readb, s);
+    register_ioport_read (conf.port + 6, 10, 2, gus_readw, s);
+
+
+    register_ioport_write (conf.port + 0x100, 8, 1, gus_writeb, s);
+    register_ioport_write (conf.port + 0x100, 8, 2, gus_writew, s);
+    register_ioport_read (conf.port + 0x100, 8, 1, gus_readb, s);
+    register_ioport_read (conf.port + 0x100, 8, 2, gus_readw, s);
+
+    DMA_register_channel (conf.dma, GUS_read_DMA, s);
+    s->emu.gusirq = conf.irq;
+    s->emu.gusdma = conf.dma;
+    s->emu.himemaddr = s->himem;
+    s->emu.gusdatapos = s->emu.himemaddr + 1024 * 1024 + 32;
+    s->emu.opaque = s;
+    s->freq = conf.freq;
+    s->pic = pic;
+
+    AUD_set_active_out (s->voice, 1);
+    return 0;
+}
diff --git a/hw/gusemu.h b/hw/gusemu.h
new file mode 100644
index 0000000000..2e9c1c0c77
--- /dev/null
+++ b/hw/gusemu.h
@@ -0,0 +1,103 @@
+/*
+ * GUSEMU32 - API
+ *
+ * Copyright (C) 2000-2007 Tibor "TS" Schütz
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+#ifndef GUSEMU_H
+#define GUSEMU_H
+
+/* data types (need to be adjusted if neither a VC6 nor a C99 compatible compiler is used) */
+
+#if defined _WIN32 && defined _MSC_VER /* doesnt support other win32 compilers yet, do it yourself... */
+ typedef unsigned char GUSbyte;
+ typedef unsigned short GUSword;
+ typedef unsigned int GUSdword;
+ typedef signed char GUSchar;
+#else
+ #include <stdint.h>
+ typedef int8_t GUSchar;
+ typedef uint8_t GUSbyte;
+ typedef uint16_t GUSword;
+ typedef uint32_t GUSdword;
+#endif
+
+typedef struct _GUSEmuState
+{
+ GUSbyte *himemaddr; /* 1024*1024 bytes used for storing uploaded samples (+32 additional bytes for read padding) */
+ GUSbyte *gusdatapos; /* (gusdataend-gusdata) bytes used for storing emulated GF1/mixer register states (32*32+4 bytes in initial GUSemu32 version) */
+ int gusirq;
+ int gusdma;
+ unsigned int timer1fraction;
+ unsigned int timer2fraction;
+ void *opaque;
+} GUSEmuState;
+
+/* ** Callback functions needed: */
+/* NMI is defined as hwirq=-1 (not supported (yet?)) */
+/* GUS_irqrequest returns the number of IRQs actually scheduled into the virtual machine */
+/* Level triggered IRQ simulations normally return 1 */
+/* Event triggered IRQ simulation can safely ignore GUS_irqclear calls */
+int  GUS_irqrequest(GUSEmuState *state, int hwirq, int num);/* needed in both mixer and bus emulation functions. */
+void GUS_irqclear(  GUSEmuState *state, int hwirq); /* used by gus_write() only - can be left empty for mixer functions */
+void GUS_dmarequest(GUSEmuState *state);            /* used by gus_write() only - can be left empty for mixer functions */
+
+/* ** ISA bus interface functions: */
+
+/* Port I/O handlers */
+/* support the following ports: */
+/* 2x0,2x6,2x8...2xF,3x0...3x7;  */
+/* optional: 388,389 (at least writes should be forwarded or some GUS detection algorithms will fail) */
+/* data is passed in host byte order */
+unsigned int gus_read( GUSEmuState *state, int port, int size);
+void         gus_write(GUSEmuState *state, int port, int size, unsigned int data);
+/* size is given in bytes (1 for byte, 2 for word) */
+
+/* DMA data transfer function */
+/* data pointed to is passed in native x86 order */
+void gus_dma_transferdata(GUSEmuState *state, char *dma_addr, unsigned int count, int TC);
+/* Called back by GUS_start_DMA as soon as the emulated DMA controller is ready for a transfer to or from GUS */
+/* (might be immediately if the DMA controller was programmed first) */
+/* dma_addr is an already translated address directly pointing to the beginning of the memory block */
+/* do not forget to update DMA states after the call, including the DREQ and TC flags */
+/* it is possible to break down a single transfer into multiple ones, but take care that: */
+/* -dma_count is actually count-1 */
+/* -before and during a transfer, DREQ is set and TC cleared */
+/* -when calling gus_dma_transferdata(), TC is only set true for call transfering the last byte */
+/* -after the last transfer, DREQ is cleared and TC is set */
+
+/* ** GF1 mixer emulation functions: */
+/* Usually, gus_irqgen should be called directly after gus_mixvoices if you can meet the recommended ranges. */
+/* If the interrupts are executed immediately (i.e., are synchronous), it may be useful to break this */
+/* down into a sequence of gus_mixvoice();gus_irqgen(); calls while mixing an audio block. */
+/* If the interrupts are asynchronous, it may be needed to use a separate thread mixing into a temporary */
+/* audio buffer in order to avoid quality loss caused by large numsamples and elapsed_time values. */
+
+void gus_mixvoices(GUSEmuState *state, unsigned int playback_freq, unsigned int numsamples, short *bufferpos);
+/* recommended range: 10 < numsamples < 100 */
+/* lower values may result in increased rounding error, higher values often cause audible timing delays */
+
+void gus_irqgen(GUSEmuState *state, unsigned int elapsed_time);
+/* recommended range: 80us < elapsed_time < max(1000us, numsamples/playback_freq) */
+/* lower values won´t provide any benefit at all, higher values can cause audible timing delays */
+/* note: masked timers are also calculated by this function, thus it might be needed even without any IRQs in use! */
+
+#endif  /* gusemu.h */
diff --git a/hw/gusemu_hal.c b/hw/gusemu_hal.c
new file mode 100644
index 0000000000..c6f9537483
--- /dev/null
+++ b/hw/gusemu_hal.c
@@ -0,0 +1,554 @@
+/*
+ * GUSEMU32 - bus interface part
+ *
+ * Copyright (C) 2000-2007 Tibor "TS" Schütz
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+/*
+ * TODO: check mixer: see 7.20 of sdk for panning pos (applies to all gus models?)?
+ */
+
+#include "gustate.h"
+#include "gusemu.h"
+
+#define GUSregb(position) (*            (gusptr+(position)))
+#define GUSregw(position) (*(GUSword *) (gusptr+(position)))
+#define GUSregd(position) (*(GUSdword *)(gusptr+(position)))
+
+/* size given in bytes */
+unsigned int gus_read(GUSEmuState * state, int port, int size)
+{
+    int             value_read = 0;
+
+    GUSbyte        *gusptr;
+    gusptr = state->gusdatapos;
+    GUSregd(portaccesses)++;
+
+    switch (port & 0xff0f)
+    {
+        /* MixerCtrlReg (read not supported on GUS classic) */
+        /* case 0x200: return GUSregb(MixerCtrlReg2x0); */
+    case 0x206:                          /* IRQstatReg / SB2x6IRQ */
+        /* adlib/sb bits set in port handlers */
+        /* timer/voice bits set in gus_irqgen() */
+        /* dma bit set in gus_dma_transferdata */
+        /* midi not implemented yet */
+        return GUSregb(IRQStatReg2x6);
+    /* case 0x308:                       */ /* AdLib388 */
+    case 0x208:
+        if (GUSregb(GUS45TimerCtrl) & 1)
+            return GUSregb(TimerStatus2x8);
+        return GUSregb(AdLibStatus2x8);  /* AdLibStatus */
+    case 0x309:                          /* AdLib389 */
+    case 0x209:
+        return GUSregb(AdLibData2x9);    /* AdLibData */
+    case 0x20A:
+        return GUSregb(AdLibCommand2xA); /* AdLib2x8_2xA */
+
+#if 0
+    case 0x20B:                          /* GUS hidden registers (read not supported on GUS classic) */
+        switch (GUSregb(RegCtrl_2xF) & 0x07)
+        {
+        case 0:                                 /* IRQ/DMA select */
+            if (GUSregb(MixerCtrlReg2x0) & 0x40)
+                return GUSregb(IRQ_2xB);        /* control register select bit */
+            else
+                return GUSregb(DMA_2xB);
+            /* case 1-5:                        */ /* general purpose emulation regs  */
+            /*  return ...                      */ /* + status reset reg (write only) */
+        case 6:
+            return GUSregb(Jumper_2xB);         /* Joystick/MIDI enable (JumperReg) */
+        default:;
+        }
+        break;
+#endif
+
+    case 0x20C:                          /* SB2xCd */
+        value_read = GUSregb(SB2xCd);
+        if (GUSregb(StatRead_2xF) & 0x20)
+            GUSregb(SB2xCd) ^= 0x80; /* toggle MSB on read */
+        return value_read;
+        /* case 0x20D:                   */ /* SB2xD is write only -> 2xE writes to it*/
+    case 0x20E:
+        if (GUSregb(RegCtrl_2xF) & 0x80) /* 2xE read IRQ enabled? */
+        {
+            GUSregb(StatRead_2xF) |= 0x80;
+            GUS_irqrequest(state, state->gusirq, 1);
+        }
+        return GUSregb(SB2xE);           /* SB2xE */
+    case 0x20F:                          /* StatRead_2xF */
+        /*set/clear fixed bits */
+        /*value_read = (GUSregb(StatRead_2xF) & 0xf9)|1; */ /*(LSB not set on GUS classic!)*/
+        value_read = (GUSregb(StatRead_2xF) & 0xf9);
+        if (GUSregb(MixerCtrlReg2x0) & 0x08)
+            value_read |= 2;    /* DMA/IRQ enabled flag */
+        return value_read;
+    /* case 0x300:                      */ /* MIDI (not implemented) */
+    /* case 0x301:                      */ /* MIDI (not implemented) */
+    case 0x302:
+        return GUSregb(VoiceSelReg3x2); /* VoiceSelReg */
+    case 0x303:
+        return GUSregb(FunkSelReg3x3);  /* FunkSelReg */
+    case 0x304:                         /* DataRegLoByte3x4 + DataRegWord3x4 */
+    case 0x305:                         /* DataRegHiByte3x5 */
+        switch (GUSregb(FunkSelReg3x3))
+        {
+    /* common functions */
+        case 0x41:                      /* DramDMAContrReg */
+            value_read = GUSregb(GUS41DMACtrl); /* &0xfb */
+            GUSregb(GUS41DMACtrl) &= 0xbb;
+            if (state->gusdma >= 4)
+                value_read |= 0x04;
+            if (GUSregb(IRQStatReg2x6) & 0x80)
+            {
+                value_read |= 0x40;
+                GUSregb(IRQStatReg2x6) &= 0x7f;
+                if (!GUSregb(IRQStatReg2x6))
+                    GUS_irqclear(state, state->gusirq);
+            }
+            return (GUSbyte) value_read;
+            /* DramDMAmemPosReg */
+            /* case 0x42: value_read=GUSregw(GUS42DMAStart); break;*/
+            /* 43h+44h write only */
+        case 0x45:
+            return GUSregb(GUS45TimerCtrl);         /* TimerCtrlReg */
+            /* 46h+47h write only */
+            /* 48h: samp freq - write only */
+        case 0x49:
+            return GUSregb(GUS49SampCtrl) & 0xbf;   /* SampCtrlReg */
+        /* case 4bh:                                */ /* joystick trim not supported */
+        /* case 0x4c: return GUSregb(GUS4cReset);   */ /* GUSreset: write only*/
+    /* voice specific functions */
+        case 0x80:
+        case 0x81:
+        case 0x82:
+        case 0x83:
+        case 0x84:
+        case 0x85:
+        case 0x86:
+        case 0x87:
+        case 0x88:
+        case 0x89:
+        case 0x8a:
+        case 0x8b:
+        case 0x8c:
+        case 0x8d:
+            {
+                int             offset = 2 * (GUSregb(FunkSelReg3x3) & 0x0f);
+                offset += ((int) GUSregb(VoiceSelReg3x2) & 0x1f) << 5; /* = Voice*32 + Funktion*2 */
+                value_read = GUSregw(offset);
+            }
+            break;
+    /* voice unspecific functions */
+        case 0x8e:                                  /* NumVoice */
+            return GUSregb(NumVoices);
+        case 0x8f:                                  /* irqstatreg */
+            /* (pseudo IRQ-FIFO is processed during a gus_write(0x3X3,0x8f)) */
+            return GUSregb(SynVoiceIRQ8f);
+        default:
+            return 0xffff;
+        }
+        if (size == 1)
+        {
+            if ((port & 0xff0f) == 0x305)
+                value_read = value_read >> 8;
+            value_read &= 0xff;
+        }
+        return (GUSword) value_read;
+    /* case 0x306:                                  */ /* Mixer/Version info */
+        /*  return 0xff; */ /* Pre 3.6 boards, ICS mixer NOT present */
+    case 0x307:                                     /* DRAMaccess */
+        {
+            GUSbyte        *adr;
+            adr = state->himemaddr + (GUSregd(GUSDRAMPOS24bit) & 0xfffff);
+            return *adr;
+        }
+    default:;
+    }
+    return 0xffff;
+}
+
+void gus_write(GUSEmuState * state, int port, int size, unsigned int data)
+{
+    GUSbyte        *gusptr;
+    gusptr = state->gusdatapos;
+    GUSregd(portaccesses)++;
+
+    switch (port & 0xff0f)
+    {
+    case 0x200:                 /* MixerCtrlReg */
+        GUSregb(MixerCtrlReg2x0) = (GUSbyte) data;
+        break;
+    case 0x206:                 /* IRQstatReg / SB2x6IRQ */
+        if (GUSregb(GUS45TimerCtrl) & 0x20) /* SB IRQ enabled? -> set 2x6IRQ bit */
+        {
+            GUSregb(TimerStatus2x8) |= 0x08;
+            GUSregb(IRQStatReg2x6) = 0x10;
+            GUS_irqrequest(state, state->gusirq, 1);
+        }
+        break;
+    case 0x308:                /* AdLib 388h */
+    case 0x208:                /* AdLibCommandReg */
+        GUSregb(AdLibCommand2xA) = (GUSbyte) data;
+        break;
+    case 0x309:                /* AdLib 389h */
+    case 0x209:                /* AdLibDataReg */
+        if ((GUSregb(AdLibCommand2xA) == 0x04) && (!(GUSregb(GUS45TimerCtrl) & 1))) /* GUS auto timer mode enabled? */
+        {
+            if (data & 0x80)
+                GUSregb(TimerStatus2x8) &= 0x1f; /* AdLib IRQ reset? -> clear maskable adl. timer int regs */
+            else
+                GUSregb(TimerDataReg2x9) = (GUSbyte) data;
+        }
+        else
+        {
+            GUSregb(AdLibData2x9) = (GUSbyte) data;
+            if (GUSregb(GUS45TimerCtrl) & 0x02)
+            {
+                GUSregb(TimerStatus2x8) |= 0x01;
+                GUSregb(IRQStatReg2x6) = 0x10;
+                GUS_irqrequest(state, state->gusirq, 1);
+            }
+        }
+        break;
+    case 0x20A:
+        GUSregb(AdLibStatus2x8) = (GUSbyte) data;
+        break;                 /* AdLibStatus2x8 */
+    case 0x20B:                /* GUS hidden registers */
+        switch (GUSregb(RegCtrl_2xF) & 0x7)
+        {
+        case 0:
+            if (GUSregb(MixerCtrlReg2x0) & 0x40)
+                GUSregb(IRQ_2xB) = (GUSbyte) data; /* control register select bit */
+            else
+                GUSregb(DMA_2xB) = (GUSbyte) data;
+            break;
+            /* case 1-4: general purpose emulation regs */
+        case 5:                                    /* clear stat reg 2xF */
+            GUSregb(StatRead_2xF) = 0; /* ToDo: is this identical with GUS classic? */
+            if (!GUSregb(IRQStatReg2x6))
+                GUS_irqclear(state, state->gusirq);
+            break;
+        case 6:                                    /* Jumper reg (Joystick/MIDI enable) */
+            GUSregb(Jumper_2xB) = (GUSbyte) data;
+            break;
+        default:;
+        }
+        break;
+    case 0x20C:                /* SB2xCd */
+        if (GUSregb(GUS45TimerCtrl) & 0x20)
+        {
+            GUSregb(TimerStatus2x8) |= 0x10; /* SB IRQ enabled? -> set 2xCIRQ bit */
+            GUSregb(IRQStatReg2x6) = 0x10;
+            GUS_irqrequest(state, state->gusirq, 1);
+        }
+    case 0x20D:                /* SB2xCd no IRQ */
+        GUSregb(SB2xCd) = (GUSbyte) data;
+        break;
+    case 0x20E:                /* SB2xE */
+        GUSregb(SB2xE) = (GUSbyte) data;
+        break;
+    case 0x20F:
+        GUSregb(RegCtrl_2xF) = (GUSbyte) data;
+        break;                 /* CtrlReg2xF */
+    case 0x302:                /* VoiceSelReg */
+        GUSregb(VoiceSelReg3x2) = (GUSbyte) data;
+        break;
+    case 0x303:                /* FunkSelReg */
+        GUSregb(FunkSelReg3x3) = (GUSbyte) data;
+        if ((GUSbyte) data == 0x8f) /* set irqstatreg, get voicereg and clear IRQ */
+        {
+            int             voice;
+            if (GUSregd(voicewavetableirq)) /* WavetableIRQ */
+            {
+                for (voice = 0; voice < 31; voice++)
+                {
+                    if (GUSregd(voicewavetableirq) & (1 << voice))
+                    {
+                        GUSregd(voicewavetableirq) ^= (1 << voice); /* clear IRQ bit */
+                        GUSregb(voice << 5) &= 0x7f; /* clear voice reg irq bit */
+                        if (!GUSregd(voicewavetableirq))
+                            GUSregb(IRQStatReg2x6) &= 0xdf;
+                        if (!GUSregb(IRQStatReg2x6))
+                            GUS_irqclear(state, state->gusirq);
+                        GUSregb(SynVoiceIRQ8f) = voice | 0x60; /* (bit==0 => IRQ wartend) */
+                        return;
+                    }
+                }
+            }
+            else if (GUSregd(voicevolrampirq)) /* VolRamp IRQ */
+            {
+                for (voice = 0; voice < 31; voice++)
+                {
+                    if (GUSregd(voicevolrampirq) & (1 << voice))
+                    {
+                        GUSregd(voicevolrampirq) ^= (1 << voice); /* clear IRQ bit */
+                        GUSregb((voice << 5) + VSRVolRampControl) &= 0x7f; /* clear voice volume reg irq bit */
+                        if (!GUSregd(voicevolrampirq))
+                            GUSregb(IRQStatReg2x6) &= 0xbf;
+                        if (!GUSregb(IRQStatReg2x6))
+                            GUS_irqclear(state, state->gusirq);
+                        GUSregb(SynVoiceIRQ8f) = voice | 0x80; /* (bit==0 => IRQ wartend) */
+                        return;
+                    }
+                }
+            }
+            GUSregb(SynVoiceIRQ8f) = 0xe8; /* kein IRQ wartet */
+        }
+        break;
+    case 0x304:
+    case 0x305:
+        {
+            GUSword         writedata = (GUSword) data;
+            GUSword         readmask = 0x0000;
+            if (size == 1)
+            {
+                readmask = 0xff00;
+                writedata &= 0xff;
+                if ((port & 0xff0f) == 0x305)
+                {
+                    writedata = (GUSword) (writedata << 8);
+                    readmask = 0x00ff;
+                }
+            }
+            switch (GUSregb(FunkSelReg3x3))
+            {
+                /* voice specific functions */
+            case 0x00:
+            case 0x01:
+            case 0x02:
+            case 0x03:
+            case 0x04:
+            case 0x05:
+            case 0x06:
+            case 0x07:
+            case 0x08:
+            case 0x09:
+            case 0x0a:
+            case 0x0b:
+            case 0x0c:
+            case 0x0d:
+                {
+                    int             offset;
+                    if (!(GUSregb(GUS4cReset) & 0x01))
+                        break;  /* reset flag active? */
+                    offset = 2 * (GUSregb(FunkSelReg3x3) & 0x0f);
+                    offset += (GUSregb(VoiceSelReg3x2) & 0x1f) << 5; /*  = Voice*32 + Funktion*2 */
+                    GUSregw(offset) = (GUSword) ((GUSregw(offset) & readmask) | writedata);
+                }
+                break;
+                /* voice unspecific functions */
+            case 0x0e:         /* NumVoices */
+                GUSregb(NumVoices) = (GUSbyte) data;
+                break;
+            /* case 0x0f:      */ /* read only */
+                /* common functions */
+            case 0x41:         /* DramDMAContrReg */
+                GUSregb(GUS41DMACtrl) = (GUSbyte) data;
+                if (data & 0x01)
+                    GUS_dmarequest(state);
+                break;
+            case 0x42:         /* DramDMAmemPosReg */
+                GUSregw(GUS42DMAStart) = (GUSregw(GUS42DMAStart) & readmask) | writedata;
+                GUSregb(GUS50DMAHigh) &= 0xf; /* compatibility stuff... */
+                break;
+            case 0x43:         /* DRAMaddrLo */
+                GUSregd(GUSDRAMPOS24bit) =
+                    (GUSregd(GUSDRAMPOS24bit) & (readmask | 0xff0000)) | writedata;
+                break;
+            case 0x44:         /* DRAMaddrHi */
+                GUSregd(GUSDRAMPOS24bit) =
+                    (GUSregd(GUSDRAMPOS24bit) & 0xffff) | ((data & 0x0f) << 16);
+                break;
+            case 0x45:         /* TCtrlReg */
+                GUSregb(GUS45TimerCtrl) = (GUSbyte) data;
+                if (!(data & 0x20))
+                    GUSregb(TimerStatus2x8) &= 0xe7;    /* sb IRQ dis? -> clear 2x8/2xC sb IRQ flags */
+                if (!(data & 0x02))
+                    GUSregb(TimerStatus2x8) &= 0xfe;    /* adlib data IRQ dis? -> clear 2x8 adlib IRQ flag */
+                if (!(GUSregb(TimerStatus2x8) & 0x19))
+                    GUSregb(IRQStatReg2x6) &= 0xef;     /* 0xe6; $$clear IRQ if both IRQ bits are inactive or cleared */
+                /* catch up delayed timer IRQs: */
+                if ((GUSregw(TimerIRQs) > 1) && (GUSregb(TimerDataReg2x9) & 3))
+                {
+                    if (GUSregb(TimerDataReg2x9) & 1)   /* start timer 1 (80us decrement rate) */
+                    {
+                        if (!(GUSregb(TimerDataReg2x9) & 0x40))
+                            GUSregb(TimerStatus2x8) |= 0xc0;    /* maskable bits */
+                        if (data & 4) /* timer1 irq enable */
+                        {
+                            GUSregb(TimerStatus2x8) |= 4;       /* nonmaskable bit */
+                            GUSregb(IRQStatReg2x6) |= 4;        /* timer 1 irq pending */
+                        }
+                    }
+                    if (GUSregb(TimerDataReg2x9) & 2)   /* start timer 2 (320us decrement rate) */
+                    {
+                        if (!(GUSregb(TimerDataReg2x9) & 0x20))
+                            GUSregb(TimerStatus2x8) |= 0xa0;    /* maskable bits */
+                        if (data & 8) /* timer2 irq enable */
+                        {
+                            GUSregb(TimerStatus2x8) |= 2;       /* nonmaskable bit */
+                            GUSregb(IRQStatReg2x6) |= 8;        /* timer 2 irq pending */
+                        }
+                    }
+                    GUSregw(TimerIRQs)--;
+                    if (GUSregw(BusyTimerIRQs) > 1)
+                        GUSregw(BusyTimerIRQs)--;
+                    else
+                        GUSregw(BusyTimerIRQs) =
+                            GUS_irqrequest(state, state->gusirq, GUSregw(TimerIRQs));
+                }
+                else
+                    GUSregw(TimerIRQs) = 0;
+
+                if (!(data & 0x04))
+                {
+                    GUSregb(TimerStatus2x8) &= 0xfb; /* clear non-maskable timer1 bit */
+                    GUSregb(IRQStatReg2x6)  &= 0xfb;
+                }
+                if (!(data & 0x08))
+                {
+                    GUSregb(TimerStatus2x8) &= 0xfd; /* clear non-maskable timer2 bit */
+                    GUSregb(IRQStatReg2x6)  &= 0xf7;
+                }
+                if (!GUSregb(IRQStatReg2x6))
+                    GUS_irqclear(state, state->gusirq);
+                break;
+            case 0x46:          /* Counter1 */
+                GUSregb(GUS46Counter1) = (GUSbyte) data;
+                break;
+            case 0x47:          /* Counter2 */
+                GUSregb(GUS47Counter2) = (GUSbyte) data;
+                break;
+            /* case 0x48:       */ /* sampling freq reg not emulated (same as interwave) */
+            case 0x49:          /* SampCtrlReg */
+                GUSregb(GUS49SampCtrl) = (GUSbyte) data;
+                break;
+            /* case 0x4b:       */ /* joystick trim not emulated */
+            case 0x4c:          /* GUSreset */
+                GUSregb(GUS4cReset) = (GUSbyte) data;
+                if (!(GUSregb(GUS4cReset) & 1)) /* reset... */
+                {
+                    GUSregd(voicewavetableirq) = 0;
+                    GUSregd(voicevolrampirq) = 0;
+                    GUSregw(TimerIRQs) = 0;
+                    GUSregw(BusyTimerIRQs) = 0;
+                    GUSregb(NumVoices) = 0xcd;
+                    GUSregb(IRQStatReg2x6) = 0;
+                    GUSregb(TimerStatus2x8) = 0;
+                    GUSregb(AdLibData2x9) = 0;
+                    GUSregb(TimerDataReg2x9) = 0;
+                    GUSregb(GUS41DMACtrl) = 0;
+                    GUSregb(GUS45TimerCtrl) = 0;
+                    GUSregb(GUS49SampCtrl) = 0;
+                    GUSregb(GUS4cReset) &= 0xf9; /* clear IRQ and DAC enable bits */
+                    GUS_irqclear(state, state->gusirq);
+                }
+                /* IRQ enable bit checked elsewhere */
+                /* EnableDAC bit may be used by external callers */
+                break;
+            }
+        }
+        break;
+    case 0x307:                /* DRAMaccess */
+        {
+            GUSbyte        *adr;
+            adr = state->himemaddr + (GUSregd(GUSDRAMPOS24bit) & 0xfffff);
+            *adr = (GUSbyte) data;
+        }
+        break;
+    }
+}
+
+/* Attention when breaking up a single DMA transfer to multiple ones:
+ * it may lead to multiple terminal count interrupts and broken transfers:
+ *
+ * 1. Whenever you transfer a piece of data, the gusemu callback is invoked
+ * 2. The callback may generate a TC irq (if the register was set up to do so)
+ * 3. The irq may result in the program using the GUS to reprogram the GUS
+ *
+ * Some programs also decide to upload by just checking if TC occurs
+ * (via interrupt or a cleared GUS dma flag)
+ * and then start the next transfer, without checking DMA state
+ *
+ * Thus: Always make sure to set the TC flag correctly!
+ *
+ * Note that the genuine GUS had a granularity of 16 bytes/words for low/high DMA
+ * while later cards had atomic granularity provided by an additional GUS50DMAHigh register
+ * GUSemu also uses this register to support byte-granular transfers for better compatibility
+ * with emulators other than GUSemu32
+ */
+
+void gus_dma_transferdata(GUSEmuState * state, char *dma_addr, unsigned int count, int TC)
+{
+    /* this function gets called by the callback function as soon as a DMA transfer is about to start
+     * dma_addr is a translated address within accessible memory, not the physical one,
+     * count is (real dma count register)+1
+     * note that the amount of bytes transfered is fully determined by values in the DMA registers
+     * do not forget to update DMA states after transferring the entire block:
+     * DREQ cleared & TC asserted after the _whole_ transfer */
+
+    char           *srcaddr;
+    char           *destaddr;
+    char            msbmask = 0;
+    GUSbyte        *gusptr;
+    gusptr = state->gusdatapos;
+
+    srcaddr = dma_addr; /* system memory address */
+    {
+        int             offset = (GUSregw(GUS42DMAStart) << 4) + (GUSregb(GUS50DMAHigh) & 0xf);
+        if (state->gusdma >= 4)
+            offset = (offset & 0xc0000) + (2 * (offset & 0x1fff0)); /* 16 bit address translation */
+        destaddr = (char *) state->himemaddr + offset; /* wavetable RAM adress */
+    }
+
+    GUSregw(GUS42DMAStart) += (GUSword)  (count >> 4);                           /* ToDo: add 16bit GUS page limit? */
+    GUSregb(GUS50DMAHigh)   = (GUSbyte) ((count + GUSregb(GUS50DMAHigh)) & 0xf); /* ToDo: add 16bit GUS page limit? */
+
+    if (GUSregb(GUS41DMACtrl) & 0x02)   /* direction, 0 := sysram->gusram */
+    {
+        char           *tmpaddr = destaddr;
+        destaddr = srcaddr;
+        srcaddr = tmpaddr;
+    }
+
+    if ((GUSregb(GUS41DMACtrl) & 0x80) && (!(GUSregb(GUS41DMACtrl) & 0x02)))
+        msbmask = (const char) 0x80;    /* invert MSB */
+    for (; count > 0; count--)
+    {
+        if (GUSregb(GUS41DMACtrl) & 0x40)
+            *(destaddr++) = *(srcaddr++);               /* 16 bit lobyte */
+        else
+            *(destaddr++) = (msbmask ^ (*(srcaddr++))); /* 8 bit */
+        if (state->gusdma >= 4)
+            *(destaddr++) = (msbmask ^ (*(srcaddr++))); /* 16 bit hibyte */
+    }
+
+    if (TC)
+    {
+        (GUSregb(GUS41DMACtrl)) &= 0xfe;        /* clear DMA request bit */
+        if (GUSregb(GUS41DMACtrl) & 0x20)       /* DMA terminal count IRQ */
+        {
+            GUSregb(IRQStatReg2x6) |= 0x80;
+            GUS_irqrequest(state, state->gusirq, 1);
+        }
+    }
+}
diff --git a/hw/gusemu_mixer.c b/hw/gusemu_mixer.c
new file mode 100644
index 0000000000..b3b5aa5d79
--- /dev/null
+++ b/hw/gusemu_mixer.c
@@ -0,0 +1,240 @@
+/*
+ * GUSEMU32 - mixing engine (similar to Interwave GF1 compatibility)
+ *
+ * Copyright (C) 2000-2007 Tibor "TS" Schütz
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+#include "gusemu.h"
+#include "gustate.h"
+
+#define GUSregb(position)  (*            (gusptr+(position)))
+#define GUSregw(position)  (*(GUSword *) (gusptr+(position)))
+#define GUSregd(position)  (*(GUSdword *)(gusptr+(position)))
+
+#define GUSvoice(position) (*(GUSword *)(voiceptr+(position)))
+
+/* samples are always 16bit stereo (4 bytes each, first right then left interleaved) */
+void gus_mixvoices(GUSEmuState * state, unsigned int playback_freq, unsigned int numsamples,
+                   short *bufferpos)
+{
+    /* note that byte registers are stored in the upper half of each voice register! */
+    GUSbyte        *gusptr;
+    int             Voice;
+    GUSword        *voiceptr;
+
+    unsigned int    count;
+    for (count = 0; count < numsamples * 2; count++)
+        *(bufferpos + count) = 0;       /* clear */
+
+    gusptr = state->gusdatapos;
+    voiceptr = (GUSword *) gusptr;
+    if (!(GUSregb(GUS4cReset) & 0x01))  /* reset flag active? */
+        return;
+
+    for (Voice = 0; Voice <= (GUSregb(NumVoices) & 31); Voice++)
+    {
+        if (GUSvoice(wVSRControl)        &  0x200)
+            GUSvoice(wVSRControl)        |= 0x100; /* voice stop request */
+        if (GUSvoice(wVSRVolRampControl) &  0x200)
+            GUSvoice(wVSRVolRampControl) |= 0x100; /* Volume ramp stop request */
+        if (!(GUSvoice(wVSRControl) & GUSvoice(wVSRVolRampControl) & 0x100)) /* neither voice nor volume calculation active - save some time here ;) */
+        {
+            unsigned int    sample;
+
+            unsigned int    LoopStart = (GUSvoice(wVSRLoopStartHi) << 16) | GUSvoice(wVSRLoopStartLo); /* 23.9 format */
+            unsigned int    LoopEnd   = (GUSvoice(wVSRLoopEndHi)   << 16) | GUSvoice(wVSRLoopEndLo);   /* 23.9 format */
+            unsigned int    CurrPos   = (GUSvoice(wVSRCurrPosHi)   << 16) | GUSvoice(wVSRCurrPosLo);   /* 23.9 format */
+            int             VoiceIncrement = ((((unsigned long) GUSvoice(wVSRFreq) * 44100) / playback_freq) * (14 >> 1)) /
+                                             ((GUSregb(NumVoices) & 31) + 1); /* 6.10 increment/frame to 23.9 increment/sample */
+
+            int             PanningPos = (GUSvoice(wVSRPanning) >> 8) & 0xf;
+
+            unsigned int    Volume32   = 32 * GUSvoice(wVSRCurrVol); /* 32 times larger than original gus for maintaining precision while ramping */
+            unsigned int    StartVol32 = (GUSvoice(wVSRVolRampStartVol) & 0xff00) * 32;
+            unsigned int    EndVol32   = (GUSvoice(wVSRVolRampEndVol)   & 0xff00) * 32;
+            int             VolumeIncrement32 = (32 * 16 * (GUSvoice(wVSRVolRampRate) & 0x3f00) >> 8) >> ((((GUSvoice(wVSRVolRampRate) & 0xc000) >> 8) >> 6) * 3); /* including 1/8/64/512 volume speed divisor */
+            VolumeIncrement32 = (((VolumeIncrement32 * 44100 / 2) / playback_freq) * 14) / ((GUSregb(NumVoices) & 31) + 1); /* adjust ramping speed to playback speed */
+
+            if (GUSvoice(wVSRControl) & 0x4000)
+                VoiceIncrement    = -VoiceIncrement;    /* reverse playback */
+            if (GUSvoice(wVSRVolRampControl) & 0x4000)
+                VolumeIncrement32 = -VolumeIncrement32; /* reverse ramping */
+
+            for (sample = 0; sample < numsamples; sample++)
+            {
+                int             sample1, sample2, Volume;
+                if (GUSvoice(wVSRControl) & 0x400)      /* 16bit */
+                {
+                    int offset = ((CurrPos >> 9) & 0xc0000) + (((CurrPos >> 9) & 0x1ffff) << 1);
+                    GUSchar *adr;
+                    adr = (GUSchar *) state->himemaddr + offset;
+                    sample1 = (*adr & 0xff) + (*(adr + 1) * 256);
+                    sample2 = (*(adr + 2) & 0xff) + (*(adr + 2 + 1) * 256);
+                }
+                else            /* 8bit */
+                {
+                    int offset = (CurrPos >> 9) & 0xfffff;
+                    GUSchar *adr;
+                    adr = (GUSchar *) state->himemaddr + offset;
+                    sample1 = (*adr) * 256;
+                    sample2 = (*(adr + 1)) * 256;
+                }
+
+                Volume = ((((Volume32 >> (4 + 5)) & 0xff) + 256) << (Volume32 >> ((4 + 8) + 5))) / 512; /* semi-logarithmic volume, +5 due to additional precision */
+                sample1 = (((sample1 * Volume) >> 16) * (512 - (CurrPos % 512))) / 512;
+                sample2 = (((sample2 * Volume) >> 16) * (CurrPos % 512)) / 512;
+                sample1 += sample2;
+
+                if (!(GUSvoice(wVSRVolRampControl) & 0x100))
+                {
+                    Volume32 += VolumeIncrement32;
+                    if ((GUSvoice(wVSRVolRampControl) & 0x4000) ? (Volume32 <= StartVol32) : (Volume32 >= EndVol32)) /* ramp up boundary cross */
+                    {
+                        if (GUSvoice(wVSRVolRampControl) & 0x2000)
+                            GUSvoice(wVSRVolRampControl) |= 0x8000;     /* volramp IRQ enabled? -> IRQ wait flag */
+                        if (GUSvoice(wVSRVolRampControl) & 0x800)       /* loop enabled */
+                        {
+                            if (GUSvoice(wVSRVolRampControl) & 0x1000)  /* bidir. loop */
+                            {
+                                GUSvoice(wVSRVolRampControl) ^= 0x4000; /* toggle dir */
+                                VolumeIncrement32 = -VolumeIncrement32;
+                            }
+                            else
+                                Volume32 = (GUSvoice(wVSRVolRampControl) & 0x4000) ? EndVol32 : StartVol32; /* unidir. loop ramp */
+                        }
+                        else
+                        {
+                            GUSvoice(wVSRVolRampControl) |= 0x100;
+                            Volume32 =
+                                (GUSvoice(wVSRVolRampControl) & 0x4000) ? StartVol32 : EndVol32;
+                        }
+                    }
+                }
+                if ((GUSvoice(wVSRVolRampControl) & 0xa000) == 0xa000)  /* volramp IRQ set and enabled? */
+                {
+                    GUSregd(voicevolrampirq) |= 1 << Voice;             /* set irq slot */
+                }
+                else
+                {
+                    GUSregd(voicevolrampirq) &= (~(1 << Voice));        /* clear irq slot */
+                    GUSvoice(wVSRVolRampControl) &= 0x7f00;
+                }
+
+                if (!(GUSvoice(wVSRControl) & 0x100))
+                {
+                    CurrPos += VoiceIncrement;
+                    if ((GUSvoice(wVSRControl) & 0x4000) ? (CurrPos <= LoopStart) : (CurrPos >= LoopEnd)) /* playback boundary cross */
+                    {
+                        if (GUSvoice(wVSRControl) & 0x2000)
+                            GUSvoice(wVSRControl) |= 0x8000;       /* voice IRQ enabled -> IRQ wait flag */
+                        if (GUSvoice(wVSRControl) & 0x800)         /* loop enabled */
+                        {
+                            if (GUSvoice(wVSRControl) & 0x1000)    /* pingpong loop */
+                            {
+                                GUSvoice(wVSRControl) ^= 0x4000;   /* toggle dir */
+                                VoiceIncrement = -VoiceIncrement;
+                            }
+                            else
+                                CurrPos = (GUSvoice(wVSRControl) & 0x4000) ? LoopEnd : LoopStart; /* unidir. loop */
+                        }
+                        else if (!(GUSvoice(wVSRVolRampControl) & 0x400))
+                            GUSvoice(wVSRControl) |= 0x100;        /* loop disabled, rollover check */
+                    }
+                }
+                if ((GUSvoice(wVSRControl) & 0xa000) == 0xa000)    /* wavetable IRQ set and enabled? */
+                {
+                    GUSregd(voicewavetableirq) |= 1 << Voice;      /* set irq slot */
+                }
+                else
+                {
+                    GUSregd(voicewavetableirq) &= (~(1 << Voice)); /* clear irq slot */
+                    GUSvoice(wVSRControl) &= 0x7f00;
+                }
+
+                /* mix samples into buffer */
+                *(bufferpos + 2 * sample)     += (short) ((sample1 * PanningPos) >> 4);        /* right */
+                *(bufferpos + 2 * sample + 1) += (short) ((sample1 * (15 - PanningPos)) >> 4); /* left */
+            }
+            /* write back voice and volume */
+            GUSvoice(wVSRCurrVol)   = Volume32 / 32;
+            GUSvoice(wVSRCurrPosHi) = CurrPos >> 16;
+            GUSvoice(wVSRCurrPosLo) = CurrPos & 0xffff;
+        }
+        voiceptr += 16; /* next voice */
+    }
+}
+
+void gus_irqgen(GUSEmuState * state, unsigned int elapsed_time)
+/* time given in microseconds */
+{
+    int             requestedIRQs = 0;
+    GUSbyte        *gusptr;
+    gusptr = state->gusdatapos;
+    if (GUSregb(TimerDataReg2x9) & 1) /* start timer 1 (80us decrement rate) */
+    {
+        unsigned int    timer1fraction = state->timer1fraction;
+        int             newtimerirqs;
+        newtimerirqs          = (elapsed_time + timer1fraction) / (80 * (256 - GUSregb(GUS46Counter1)));
+        state->timer1fraction = (elapsed_time + timer1fraction) % (80 * (256 - GUSregb(GUS46Counter1)));
+        if (newtimerirqs)
+        {
+            if (!(GUSregb(TimerDataReg2x9) & 0x40))
+                GUSregb(TimerStatus2x8) |= 0xc0; /* maskable bits */
+            if (GUSregb(GUS45TimerCtrl) & 4)     /* timer1 irq enable */
+            {
+                GUSregb(TimerStatus2x8) |= 4;    /* nonmaskable bit */
+                GUSregb(IRQStatReg2x6)  |= 4;    /* timer 1 irq pending */
+                GUSregw(TimerIRQs) += newtimerirqs;
+                requestedIRQs += newtimerirqs;
+            }
+        }
+    }
+    if (GUSregb(TimerDataReg2x9) & 2) /* start timer 2 (320us decrement rate) */
+    {
+        unsigned int timer2fraction = state->timer2fraction;
+        int             newtimerirqs;
+        newtimerirqs          = (elapsed_time + timer2fraction) / (320 * (256 - GUSregb(GUS47Counter2)));
+        state->timer2fraction = (elapsed_time + timer2fraction) % (320 * (256 - GUSregb(GUS47Counter2)));
+        if (newtimerirqs)
+        {
+            if (!(GUSregb(TimerDataReg2x9) & 0x20))
+                GUSregb(TimerStatus2x8) |= 0xa0; /* maskable bits */
+            if (GUSregb(GUS45TimerCtrl) & 8)     /* timer2 irq enable */
+            {
+                GUSregb(TimerStatus2x8) |= 2;    /* nonmaskable bit */
+                GUSregb(IRQStatReg2x6)  |= 8;    /* timer 2 irq pending */
+                GUSregw(TimerIRQs) += newtimerirqs;
+                requestedIRQs += newtimerirqs;
+            }
+        }
+    }
+    if (GUSregb(GUS4cReset) & 0x4) /* synth IRQ enable */
+    {
+        if (GUSregd(voicewavetableirq))
+            GUSregb(IRQStatReg2x6) |= 0x20;
+        if (GUSregd(voicevolrampirq))
+            GUSregb(IRQStatReg2x6) |= 0x40;
+    }
+    if ((!requestedIRQs) && GUSregb(IRQStatReg2x6))
+        requestedIRQs++;
+    if (GUSregb(IRQStatReg2x6))
+        GUSregw(BusyTimerIRQs) = GUS_irqrequest(state, state->gusirq, requestedIRQs);
+}
diff --git a/hw/gustate.h b/hw/gustate.h
new file mode 100644
index 0000000000..ece903abb9
--- /dev/null
+++ b/hw/gustate.h
@@ -0,0 +1,132 @@
+/*
+ * GUSEMU32 - persistent GUS register state
+ *
+ * Copyright (C) 2000-2007 Tibor "TS" Schütz
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+#ifndef GUSTATE_H
+#define GUSTATE_H
+
+/*state block offset*/
+#define gusdata (0)
+
+/* data stored using this structure is in host byte order! */
+
+/*access type*/
+#define PortRead  (0)
+#define PortWrite (1)
+
+#define Port8Bitacc  (0)
+#define Port16Bitacc (1)
+
+/*voice register offsets (in bytes)*/
+#define VSRegs (0)
+#define VSRControl          (0)
+#define VSRegsEnd (VSRControl+VSRegs + 32*(16*2))
+#define VSRFreq             (2)
+#define VSRLoopStartHi      (4)
+#define VSRLoopStartLo      (6)
+#define VSRLoopEndHi        (8)
+#define VSRLoopEndLo       (10)
+#define VSRVolRampRate     (12)
+#define VSRVolRampStartVol (14)
+#define VSRVolRampEndVol   (16)
+#define VSRCurrVol         (18)
+#define VSRCurrPosHi       (20)
+#define VSRCurrPosLo       (22)
+#define VSRPanning         (24)
+#define VSRVolRampControl  (26)
+
+/*voice register offsets (in words)*/
+#define wVSRegs (0)
+#define wVSRControl         (0)
+#define wVSRegsEnd (wVSRControl+wVSRegs + 32*(16))
+#define wVSRFreq            (1)
+#define wVSRLoopStartHi     (2)
+#define wVSRLoopStartLo     (3)
+#define wVSRLoopEndHi       (4)
+#define wVSRLoopEndLo       (5)
+#define wVSRVolRampRate     (6)
+#define wVSRVolRampStartVol (7)
+#define wVSRVolRampEndVol   (8)
+#define wVSRCurrVol         (9)
+#define wVSRCurrPosHi      (10)
+#define wVSRCurrPosLo      (11)
+#define wVSRPanning        (12)
+#define wVSRVolRampControl (13)
+
+/*GUS register state block: 32 voices, padding filled with remaining registers*/
+#define DataRegLoByte3x4  (VSRVolRampControl+2)
+#define  DataRegWord3x4 (DataRegLoByte3x4)
+#define DataRegHiByte3x5  (VSRVolRampControl+2       +1)
+#define DMA_2xB (VSRVolRampControl+2+2)
+#define IRQ_2xB (VSRVolRampControl+2+3)
+
+#define RegCtrl_2xF       (VSRVolRampControl+2+(16*2))
+#define Jumper_2xB        (VSRVolRampControl+2+(16*2)+1)
+#define GUS42DMAStart     (VSRVolRampControl+2+(16*2)+2)
+
+#define GUS43DRAMIOlo     (VSRVolRampControl+2+(16*2)*2)
+#define  GUSDRAMPOS24bit (GUS43DRAMIOlo)
+#define GUS44DRAMIOhi     (VSRVolRampControl+2+(16*2)*2+2)
+
+#define voicewavetableirq (VSRVolRampControl+2+(16*2)*3) /* voice IRQ pseudoqueue: 1 bit per voice */
+
+#define voicevolrampirq   (VSRVolRampControl+2+(16*2)*4) /* voice IRQ pseudoqueue: 1 bit per voice */
+
+#define startvoices       (VSRVolRampControl+2+(16*2)*5) /* statistics / optimizations */
+
+#define IRQStatReg2x6     (VSRVolRampControl+2+(16*2)*6)
+#define TimerStatus2x8    (VSRVolRampControl+2+(16*2)*6+1)
+#define TimerDataReg2x9   (VSRVolRampControl+2+(16*2)*6+2)
+#define MixerCtrlReg2x0   (VSRVolRampControl+2+(16*2)*6+3)
+
+#define VoiceSelReg3x2    (VSRVolRampControl+2+(16*2)*7)
+#define FunkSelReg3x3     (VSRVolRampControl+2+(16*2)*7+1)
+#define AdLibStatus2x8    (VSRVolRampControl+2+(16*2)*7+2)
+#define StatRead_2xF      (VSRVolRampControl+2+(16*2)*7+3)
+
+#define GUS48SampSpeed    (VSRVolRampControl+2+(16*2)*8)
+#define GUS41DMACtrl      (VSRVolRampControl+2+(16*2)*8+1)
+#define GUS45TimerCtrl    (VSRVolRampControl+2+(16*2)*8+2)
+#define GUS46Counter1     (VSRVolRampControl+2+(16*2)*8+3)
+
+#define GUS47Counter2     (VSRVolRampControl+2+(16*2)*9)
+#define GUS49SampCtrl     (VSRVolRampControl+2+(16*2)*9+1)
+#define GUS4cReset        (VSRVolRampControl+2+(16*2)*9+2)
+#define NumVoices         (VSRVolRampControl+2+(16*2)*9+3)
+
+#define TimerIRQs         (VSRVolRampControl+2+(16*2)*10)   /* delayed IRQ, statistics */
+#define BusyTimerIRQs     (VSRVolRampControl+2+(16*2)*10+2) /* delayed IRQ, statistics */
+
+#define AdLibCommand2xA   (VSRVolRampControl+2+(16*2)*11)
+#define AdLibData2x9      (VSRVolRampControl+2+(16*2)*11+1)
+#define SB2xCd            (VSRVolRampControl+2+(16*2)*11+2)
+#define SB2xE             (VSRVolRampControl+2+(16*2)*11+3)
+
+#define SynVoiceIRQ8f     (VSRVolRampControl+2+(16*2)*12)
+#define GUS50DMAHigh      (VSRVolRampControl+2+(16*2)*12+1)
+
+#define portaccesses (VSRegsEnd) /* statistics / suspend mode */
+
+#define gusdataend (VSRegsEnd+4)
+
+#endif  /* gustate.h */