/*

 * 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;