86Box/src/sound/snd_mpu401.c

/*
 * 86Box	A hypervisor and IBM PC system emulator that specializes in
 *		running old operating systems and software designed for IBM
 *		PC systems and compatibles from 1981 through fairly recent
 *		system designs based on the PCI bus.
 *
 *		This file is part of the 86Box distribution.
 *
 *		Roland MPU-401 emulation.
 *
 * Version:	@(#)snd_mpu401.c	1.0.14	2018/09/11
 *
 * Authors:	Sarah Walker, <http://pcem-emulator.co.uk/>
 *		DOSBox Team,
 *		Miran Grca, <mgrca8@gmail.com>
 *		TheCollector1995, <mariogplayer@gmail.com>
 *
 *		Copyright 2008-2018 Sarah Walker.
 *		Copyright 2008-2018 DOSBox Team.
 *		Copyright 2016-2018 Miran Grca.
 */
#include <stdarg.h>
#include <stdint.h>
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <stdarg.h>
#include <wchar.h>
#define HAVE_STDARG_H
#include "../86box.h"
#include "../device.h"
#include "../io.h"
#include "../mca.h"
#include "../pic.h"
#include "../timer.h"
#include "sound.h"
#include "snd_mpu401.h"
#include "midi.h"


enum {
    STATUS_OUTPUT_NOT_READY = 0x40,
    STATUS_INPUT_NOT_READY  = 0x80
};


int mpu401_standalone_enable = 0;

static int64_t mpu401_event_callback = 0LL;
static int64_t mpu401_eoi_callback = 0LL;
static int64_t mpu401_reset_callback = 0LL;


static void MPU401_WriteCommand(mpu_t *mpu, uint8_t val);
static void MPU401_EOIHandlerDispatch(void *p);


#ifdef ENABLE_MPU401_LOG
int mpu401_do_log = ENABLE_MPU401_LOG;
#endif


static void
mpu401_log(const char *fmt, ...)
{
#ifdef ENABLE_MPU401_LOG
    va_list ap;

    if (mpu401_do_log) {
	va_start(ap, fmt);
	pclog_ex(fmt, ap);
	va_end(ap);
    }
#endif
}

int mca_version = 0;

static void
QueueByte(mpu_t *mpu, uint8_t data) 
{
    if (mpu->state.block_ack) {
	mpu->state.block_ack = 0;
	return;
    }
	
    if ((mpu->queue_used == 0) && (mpu->mode == M_INTELLIGENT)) {
	mpu->state.irq_pending = 1;
	picint(1 << mpu->irq);
    }
    if (mpu->queue_used < MPU401_QUEUE) {
	int pos = mpu->queue_used+mpu->queue_pos;

	if (mpu->queue_pos >= MPU401_QUEUE) 
		mpu->queue_pos -= MPU401_QUEUE;

	if (pos>=MPU401_QUEUE) 
		pos-=MPU401_QUEUE;

	mpu->queue_used++;
	mpu->queue[pos] = data;
    } else
	mpu401_log("MPU401:Data queue full\n");
}


static void
ClrQueue(mpu_t *mpu) 
{
    mpu->queue_used=0;
    mpu->queue_pos=0;
}


static void
MPU401_Reset(mpu_t *mpu) 
{
    uint8_t i;

    picintc(1 << mpu->irq);

    mpu->mode = M_INTELLIGENT;
    mpu->state.eoi_scheduled = 0;
    mpu->state.wsd = 0;
    mpu->state.wsm = 0;
    mpu->state.conductor = 0;
    mpu->state.cond_req = 0;
    mpu->state.cond_set = 0;
    mpu->state.playing = 0;
    mpu->state.run_irq = 0;
    mpu->state.irq_pending = 0;
    mpu->state.cmask = 0xff;
    mpu->state.amask = mpu->state.tmask = 0;
    mpu->state.midi_mask = 0xffff;
    mpu->state.data_onoff = 0;
    mpu->state.command_byte = 0;
    mpu->state.block_ack = 0;
    mpu->clock.tempo = mpu->clock.old_tempo = 100;
    mpu->clock.timebase = mpu->clock.old_timebase = 120;
    mpu->clock.tempo_rel = mpu->clock.old_tempo_rel = 40;
    mpu->clock.tempo_grad = 0;
    mpu->clock.clock_to_host = 0;
    mpu->clock.cth_rate = 60;
    mpu->clock.cth_counter = 0;

    ClrQueue(mpu);

    mpu->state.req_mask = 0;
    mpu->condbuf.counter = 0;
    mpu->condbuf.type = T_OVERFLOW;

    for (i=0;i<8;i++) {
	mpu->playbuf[i].type = T_OVERFLOW;
	mpu->playbuf[i].counter = 0;
    }
}


static void
MPU401_ResetDone(void *priv) 
{
    mpu_t *mpu = (mpu_t *)priv;

    mpu401_log("MPU-401 reset callback\n");

    mpu401_reset_callback = 0LL;

    mpu->state.reset = 0;
    if (mpu->state.cmd_pending) {
	MPU401_WriteCommand(mpu, mpu->state.cmd_pending - 1);
	mpu->state.cmd_pending = 0;
    }
}


static void
MPU401_WriteCommand(mpu_t *mpu, uint8_t val)
{	
    uint8_t i, was_uart;

    if (mpu->state.reset)
	mpu->state.cmd_pending = val + 1;

    if ((val != 0x3f) && (val != 0xff) && !mpu->intelligent)
	return;

    if (val <= 0x2f) {
	switch (val&3) { /* MIDI stop, start, continue */
		case 1:
			midi_write(0xfc);
			break;

		case 2:
			midi_write(0xfa);
			break;

		case 3:
			midi_write(0xfb);
			break;
	}

	switch (val & 0xc) {
		case  0x4:	/* Stop */
			mpu->state.playing = 0;
			mpu401_event_callback = 0LL;

			for (i = 0xb0; i < 0xbf; i++) {
				/* All notes off */
				midi_write(i);
				midi_write(0x7b);
				midi_write(0);
			}
			break;

		case 0x8:	/* Play */
			mpu->state.playing = 1;
			mpu401_event_callback = (MPU401_TIMECONSTANT / (mpu->clock.tempo*mpu->clock.timebase)) * 1000LL * TIMER_USEC;
			ClrQueue(mpu);
			break;
	}
    } else if ((val >= 0xa0) && (val <= 0xa7)) {	/* Request play counter */
	if (mpu->state.cmask & (1 << (val&7)))
		QueueByte(mpu, mpu->playbuf[val&7].counter);
    } else if ((val >= 0xd0) && (val <= 0xd7)) {	/* Send data */
	mpu->state.old_chan = mpu->state.channel;
	mpu->state.channel= val & 7;
	mpu->state.wsd = 1;
	mpu->state.wsm = 0;
	mpu->state.wsd_start = 1;
    } else switch (val) {
	case 0xdf:	/* Send system message */
		mpu->state.wsd = 0;
		mpu->state.wsm = 1;
		mpu->state.wsd_start = 1;
		break;

	case 0x8e:	/* Conductor */
		mpu->state.cond_set = 0;
		break;

	case 0x8f:
		mpu->state.cond_set = 1;
		break;

	case 0x94: /* Clock to host */
		mpu->clock.clock_to_host = 0;
		break;

	case 0x95:
		mpu->clock.clock_to_host = 1;
		break;

	case 0xc2: /* Internal timebase */
		mpu->clock.timebase = 48;
		break;

	case 0xc3:
		mpu->clock.timebase = 72;
		break;

	case 0xc4:
		mpu->clock.timebase = 96;
		break;

	case 0xc5:
		mpu->clock.timebase = 120;
		break;

	case 0xc6:
		mpu->clock.timebase = 144;
		break;

	case 0xc7:
		mpu->clock.timebase = 168;
		break;
	case 0xc8:
		mpu->clock.timebase = 192;
		break;

	/* Commands with data byte */
	case 0xe0: case 0xe1: case 0xe2: case 0xe4: case 0xe6: 
	case 0xe7: case 0xec: case 0xed: case 0xee: case 0xef:
		mpu->state.command_byte = val;
		break;

	/* Commands 0xa# returning data */
	case 0xab:	/* Request and clear recording counter */
		QueueByte(mpu, MSG_MPU_ACK);
		QueueByte(mpu, 0);
		return;

	case 0xac:	/* Request version */
		QueueByte(mpu, MSG_MPU_ACK);
		QueueByte(mpu, MPU401_VERSION);
		return;

	case 0xad:	/* Request revision */
		QueueByte(mpu, MSG_MPU_ACK);
		QueueByte(mpu, MPU401_REVISION);
		return;

	case 0xaf:	/* Request tempo */
		QueueByte(mpu, MSG_MPU_ACK);
		QueueByte(mpu, mpu->clock.tempo);
		return;

	case 0xb1:	/* Reset relative tempo */
		mpu->clock.old_tempo_rel = mpu->clock.tempo_rel;
		mpu->clock.tempo_rel = 40;
		break;

	case 0xb9:	/* Clear play map */
	case 0xb8:	/* Clear play counters */
		for (i = 0xb0; i < 0xbf; i++) {
			/* All notes off */
			midi_write(i);
			midi_write(0x7b);
			midi_write(0);
		}
		for (i = 0; i < 8; i++) {
			mpu->playbuf[i].counter = 0;
			mpu->playbuf[i].type = T_OVERFLOW;
		}
		mpu->condbuf.counter = 0;
		mpu->condbuf.type = T_OVERFLOW;
		if (!(mpu->state.conductor=mpu->state.cond_set))
					mpu->state.cond_req = 0;
		mpu->state.amask = mpu->state.tmask;
		mpu->state.req_mask = 0;
		mpu->state.irq_pending = 1;
		break;

	case 0xff:	/* Reset MPU-401 */
		mpu401_log("MPU-401:Reset %X\n",val);
		mpu401_reset_callback = MPU401_RESETBUSY * 33LL * TIMER_USEC;
		mpu->state.reset = 1;
		was_uart = (mpu->mode == M_UART);
		MPU401_Reset(mpu);
		if (was_uart)
			return;		/* do not send ack in UART mode */
		break;

	case 0x3f:	/* UART mode */
		mpu401_log("MPU-401:Set UART mode %X\n",val);
		QueueByte(mpu, MSG_MPU_ACK);
		mpu->mode = M_UART;
		return;

	/* default:
		mpu401_log("MPU-401:Unhandled command %X",val); */
    }

    QueueByte(mpu, MSG_MPU_ACK);
}


static void
MPU401_WriteData(mpu_t *mpu, uint8_t val) 
{
    static int length, cnt, posd;

    if (mpu->mode == M_UART) {
	midi_write(val);
	return;
    }

    if (!mpu->intelligent) {
	mpu->state.command_byte = 0;
	return;
    }
	
    switch (mpu->state.command_byte) {	/* 0xe# command data */
	case 0x00:
		break;

	case 0xe0:	/* Set tempo */
		mpu->state.command_byte = 0;
		mpu->clock.tempo = val;
		return;

	case 0xe1:	/* Set relative tempo */
		mpu->state.command_byte = 0;
		mpu->clock.old_tempo_rel = mpu->clock.tempo_rel;
		mpu->clock.tempo_rel = val;
		return;

	case 0xe7:	/* Set internal clock to host interval */
		mpu->state.command_byte = 0;
		mpu->clock.cth_rate = val >> 2;
		return;

	case 0xec:	/* Set active track mask */
		mpu->state.command_byte = 0;
		mpu->state.tmask = val;
		return;

	case 0xed: /* Set play counter mask */
		mpu->state.command_byte = 0;
		mpu->state.cmask = val;
		return;

	case 0xee: /* Set 1-8 MIDI channel mask */
		mpu->state.command_byte = 0;
		mpu->state.midi_mask &= 0xff00;
		mpu->state.midi_mask |= val;
		return;

	case 0xef: /* Set 9-16 MIDI channel mask */
		mpu->state.command_byte = 0;
		mpu->state.midi_mask &= 0x00ff;
		mpu->state.midi_mask |= ((uint16_t) val) << 8;
		return;

	default:
		mpu->state.command_byte = 0;
		return;
    }

    if (mpu->state.wsd) {
	/* Directly send MIDI message */
	if (mpu->state.wsd_start) {
		mpu->state.wsd_start = 0;
		cnt = 0;
		switch (val & 0xf0) {
			case 0xc0: case 0xd0:
				mpu->playbuf[mpu->state.channel].value[0] = val;
				length = 2;
				break;

			case 0x80: case 0x90: case 0xa0: case 0xb0:case 0xe0:
				mpu->playbuf[mpu->state.channel].value[0] = val;
				length = 3;
				break;

			case 0xf0:
				/* mpu401_log("MPU-401:Illegal WSD byte\n"); */
				mpu->state.wsd = 0;
				mpu->state.channel = mpu->state.old_chan;
				return;

			default: /* MIDI with running status */
				cnt++;
				midi_write(mpu->playbuf[mpu->state.channel].value[0]);
		}
	}

	if (cnt < length) {
		midi_write(val);
		cnt++;
	}

	if (cnt == length) {
		mpu->state.wsd = 0;
		mpu->state.channel = mpu->state.old_chan;
	}

	return;
    }

    if (mpu->state.wsm) {	/* Directly send system message */
	if (val == MSG_EOX) {
		midi_write(MSG_EOX);
		mpu->state.wsm = 0;
		return;
	}
	if (mpu->state.wsd_start) {
		mpu->state.wsd_start = 0;
		cnt = 0;
		switch (val) {
			case 0xf2:
				length = 3;
				break;

			case 0xf3:
				length = 2;
				break;

			case 0xf6:
				length = 1;
				break;

			case 0xf0:
				length = 0;
				break;

			default:
				length = 0;
		}
	}

	if (!length || (cnt < length)) {
		midi_write(val);
		cnt++;
	}

	if (cnt == length)
		mpu->state.wsm = 0;

	return;
    }

    if (mpu->state.cond_req) {
	/* Command */
	switch (mpu->state.data_onoff) {
		case -1:
			return;

		case  0: /* Timing byte */
			mpu->condbuf.vlength = 0;
			if (val < 0xf0)
				mpu->state.data_onoff++;
			else {
				mpu->state.data_onoff = -1;
				MPU401_EOIHandlerDispatch(mpu);
				return;
			}

			mpu->state.send_now = !val ? 1 : 0;
			mpu->condbuf.counter = val;
			break;

		case  1: /* Command byte #1 */
			mpu->condbuf.type = T_COMMAND;
			if ((val == 0xf8) || (val == 0xf9))
				mpu->condbuf.type = T_OVERFLOW;
			mpu->condbuf.value[mpu->condbuf.vlength] = val;
			mpu->condbuf.vlength++;
			if ((val & 0xf0) != 0xe0)
				MPU401_EOIHandlerDispatch(mpu);
			else
				mpu->state.data_onoff++;
			break;

		case  2:/* Command byte #2 */
			mpu->condbuf.value[mpu->condbuf.vlength]=val;
			mpu->condbuf.vlength++;
			MPU401_EOIHandlerDispatch(mpu);
			break;
	}
	return;
    }

    switch (mpu->state.data_onoff) {
	/* Data */
	case -1:
		return;

	case 0: /* Timing byte */
		if (val < 0xf0)
			mpu->state.data_onoff = 1;
		else {
			mpu->state.data_onoff = -1;
			MPU401_EOIHandlerDispatch(mpu);
			return;
		}
		mpu->state.send_now = !val ? 1 : 0;
		mpu->playbuf[mpu->state.channel].counter = val;
		break;

	case 1: /* MIDI */
		mpu->playbuf[mpu->state.channel].vlength++;
		posd=mpu->playbuf[mpu->state.channel].vlength;
		if (posd == 1)  switch (val&0xf0) {
			case 0xf0: /* System message or mark */
				if (val > 0xf7) {
					mpu->playbuf[mpu->state.channel].type = T_MARK;
					mpu->playbuf[mpu->state.channel].sys_val = val;
				} else {
					/* mpu401_log("MPU-401:Illegal message"); */
					mpu->playbuf[mpu->state.channel].type = T_MIDI_SYS;
					mpu->playbuf[mpu->state.channel].sys_val = val;
				}
				length = 1;
				break;

			case 0xc0: case 0xd0: /* MIDI Message */
				mpu->playbuf[mpu->state.channel].type = T_MIDI_NORM;
				length = mpu->playbuf[mpu->state.channel].length = 2;
				break;

			case 0x80: case 0x90: case 0xa0:  case 0xb0: case 0xe0: 
				mpu->playbuf[mpu->state.channel].type = T_MIDI_NORM;
				length = mpu->playbuf[mpu->state.channel].length = 3;
				break;

			default: /* MIDI data with running status */
				posd++;
				mpu->playbuf[mpu->state.channel].vlength++;
				mpu->playbuf[mpu->state.channel].type = T_MIDI_NORM;
				length = mpu->playbuf[mpu->state.channel].length;
				break;
		}

		if (!((posd == 1) && (val >= 0xf0)))
			mpu->playbuf[mpu->state.channel].value[posd-1] = val;
		if (posd == length)
			MPU401_EOIHandlerDispatch(mpu);
    }
}


static void
MPU401_IntelligentOut(mpu_t *mpu, uint8_t chan) 
{
    uint8_t val;
    uint8_t i;

    switch (mpu->playbuf[chan].type) {
	case T_OVERFLOW:
		break;

	case T_MARK:
		val=mpu->playbuf[chan].sys_val;
		if (val==0xfc) {
			midi_write(val);
			mpu->state.amask &= ~(1<<chan);
			mpu->state.req_mask &= ~(1<<chan);
		}
		break;

	case T_MIDI_NORM:
		for (i = 0; i < mpu->playbuf[chan].vlength; i++)
			midi_write(mpu->playbuf[chan].value[i]);
		break;

	default:
		break;
    }
}


static void
UpdateTrack(mpu_t *mpu, uint8_t chan) 
{
    MPU401_IntelligentOut(mpu, chan);

    if (mpu->state.amask&(1<<chan)) {
	mpu->playbuf[chan].vlength = 0;
	mpu->playbuf[chan].type = T_OVERFLOW;
	mpu->playbuf[chan].counter = 0xf0;
	mpu->state.req_mask |= (1 << chan);
    } else {
	if ((mpu->state.amask == 0) && !mpu->state.conductor)
		mpu->state.req_mask |= (1 << 12);
    }
}


static void
UpdateConductor(mpu_t *mpu) 
{
    if (mpu->condbuf.value[0] == 0xfc) {
	mpu->condbuf.value[0] = 0;
	mpu->state.conductor = 0;
	mpu->state.req_mask &= ~(1 << 9);
	if (mpu->state.amask == 0)
		mpu->state.req_mask |= (1 << 12);
	return;
    }

    mpu->condbuf.vlength = 0;
    mpu->condbuf.counter = 0xf0;
    mpu->state.req_mask |= (1 << 9);
}


/* Updates counters and requests new data on "End of Input" */
static void
MPU401_EOIHandler(void *priv)
{
    mpu_t *mpu = (mpu_t *)priv;
    uint8_t i;

    mpu401_log("MPU-401 end of input callback\n");
	
    mpu401_eoi_callback = 0LL;
    mpu->state.eoi_scheduled = 0;
    if (mpu->state.send_now) {
	mpu->state.send_now = 0;
	if (mpu->state.cond_req) UpdateConductor(mpu);
	  else UpdateTrack(mpu, mpu->state.channel);
    }

    mpu->state.irq_pending = 0;

    if (!mpu->state.playing || !mpu->state.req_mask)
	return;

    i = 0;
    do {
	if (mpu->state.req_mask & (1 << i)) {
		QueueByte(mpu, 0xf0 + i);
		mpu->state.req_mask &= ~(1 << i);
		break;
	}
    } while ((i++) < 16);
}


static void
MPU401_EOIHandlerDispatch(void *priv) 
{
    mpu_t *mpu = (mpu_t *)priv;

    mpu401_log("EOI handler dispatch\n");
    if (mpu->state.send_now) {
	mpu->state.eoi_scheduled = 1;
	mpu401_eoi_callback = 60LL * TIMER_USEC; /* Possible a bit longer */
    } else if (!mpu->state.eoi_scheduled) 
	MPU401_EOIHandler(mpu);
}


static void
imf_write(uint16_t addr, uint8_t val, void *priv)
{
    mpu401_log("IMF:Wr %4X,%X\n", addr, val);
}


uint8_t
MPU401_ReadData(mpu_t *mpu)
{
    uint8_t ret;
	
    ret = MSG_MPU_ACK;
    if (mpu->queue_used) {
	if (mpu->queue_pos >= MPU401_QUEUE)
		mpu->queue_pos -= MPU401_QUEUE;
	ret = mpu->queue[mpu->queue_pos];
	mpu->queue_pos++;
	mpu->queue_used--;
    }

    /* Shouldn't this check mpu->mode? */
    if (mpu->mode == M_UART)
	return ret;

    if (mpu->queue_used == 0)
	picintc(1 << mpu->irq);

    if ((ret >= 0xf0) && (ret <= 0xf7)) {
	/* MIDI data request */
	mpu->state.channel = ret & 7;
	mpu->state.data_onoff = 0;
	mpu->state.cond_req = 0;
    }

    if (ret == MSG_MPU_COMMAND_REQ) {
	mpu->state.data_onoff = 0;
	mpu->state.cond_req = 1;
	if (mpu->condbuf.type != T_OVERFLOW) {
		mpu->state.block_ack = 1;
		MPU401_WriteCommand(mpu, mpu->condbuf.value[0]);
		if (mpu->state.command_byte)
			MPU401_WriteData(mpu, mpu->condbuf.value[1]);
	}
	mpu->condbuf.type = T_OVERFLOW;
    }

    if ((ret == MSG_MPU_END) || (ret == MSG_MPU_CLOCK) || (ret == MSG_MPU_ACK)) {
	mpu->state.data_onoff = -1;
	MPU401_EOIHandlerDispatch(mpu);
    }

    return(ret);
}


static void
mpu401_write(uint16_t addr, uint8_t val, void *priv)
{
    mpu_t *mpu = (mpu_t *)priv;
     
    /* mpu401_log("MPU401 Write Port %04X, val %x\n", addr, val); */
    switch (addr & 1) {
	case 0: /*Data*/
		MPU401_WriteData(mpu, val);
		mpu401_log("Write Data (0x330) %X\n", val);
		break;

	case 1: /*Command*/
		MPU401_WriteCommand(mpu, val);
		mpu401_log("Write Command (0x331) %x\n", val);
		break;
    }
}


static uint8_t
mpu401_read(uint16_t addr, void *priv)
{
    mpu_t *mpu = (mpu_t *)priv;
    uint8_t ret = 0;

    switch (addr & 1) {	
	case 0:		/* Read Data */
		ret = MPU401_ReadData(mpu);
		mpu401_log("Read Data (0x330) %X\n", ret);
		break;

	case 1:		/* Read Status */
		if (mpu->state.cmd_pending) ret=STATUS_OUTPUT_NOT_READY;
		if (!mpu->queue_used) ret=STATUS_INPUT_NOT_READY;
		ret |= 0x3f;

		mpu401_log("Read Status (0x331) %x\n", ret);
		break;
    }

    /* mpu401_log("MPU401 Read Port %04X, ret %x\n", addr, ret); */
    return(ret);
}


static void
MPU401_Event(void *priv) 
{
    mpu_t *mpu = (mpu_t *)priv;
    int new_time;
    uint8_t i;

    mpu401_log("MPU-401 event callback\n");

    if (mpu->mode == M_UART) {
	mpu401_event_callback = 0LL;
	return;
    }

    if (mpu->state.irq_pending) goto next_event;

    for (i = 0; i < 8; i++) { /* Decrease counters */
	if (mpu->state.amask & (1 << i)) {
		mpu->playbuf[i].counter--;
		if (mpu->playbuf[i].counter <= 0) UpdateTrack(mpu, i);
	}
    }

    if (mpu->state.conductor) {
	mpu->condbuf.counter--;
	if (mpu->condbuf.counter <= 0) UpdateConductor(mpu);
    }

    if (mpu->clock.clock_to_host) {
	mpu->clock.cth_counter++;
	if (mpu->clock.cth_counter >= mpu->clock.cth_rate) {
		mpu->clock.cth_counter = 0;
		mpu->state.req_mask |= (1 << 13);
	}
    }

    if (!mpu->state.irq_pending && mpu->state.req_mask)
	MPU401_EOIHandler(mpu);

next_event:
    new_time = ((mpu->clock.tempo * mpu->clock.timebase * mpu->clock.tempo_rel) / 0x40);
    if (new_time == 0) {
	mpu401_event_callback = 0LL;
	return;
    } else {
	mpu401_event_callback += (MPU401_TIMECONSTANT / new_time) * 1000LL * TIMER_USEC;
	mpu401_log("Next event after %i us (time constant: %i)\n", (int) ((MPU401_TIMECONSTANT/new_time) * 1000 * TIMER_USEC), (int) MPU401_TIMECONSTANT);
    }
}


void
mpu401_init(mpu_t *mpu, uint16_t addr, int irq, int mode)
{
    mpu->status = STATUS_INPUT_NOT_READY;
    mpu->irq = irq;
    mpu->queue_used = 0;
    mpu->queue_pos = 0;
    mpu->mode = M_UART;

    /* Expalantion:
	MPU-401 starting in intelligent mode = Full MPU-401 intelligent mode capability;
	MPU-401 starting in UART mode = Reduced MPU-401 intelligent mode capability seen on the Sound Blaster 16/AWE32,
					only supporting commands 3F (set UART mode) and FF (reset). */
    mpu->intelligent = (mode == M_INTELLIGENT) ? 1 : 0;
    mpu401_log("Starting as %s (mode is %s)\n", mpu->intelligent ? "INTELLIGENT" : "UART", (mode == M_INTELLIGENT) ? "INTELLIGENT" : "UART");

    mpu401_event_callback = 0LL;
    mpu401_eoi_callback = 0LL;
    mpu401_reset_callback = 0LL;

    if (addr)
	io_sethandler(addr, 2,
		      mpu401_read, NULL, NULL, mpu401_write, NULL, NULL, mpu);
    io_sethandler(0x2A20, 16,
		  NULL, NULL, NULL, imf_write, NULL, NULL, mpu);
    timer_add(MPU401_Event, &mpu401_event_callback, &mpu401_event_callback, mpu);
    timer_add(MPU401_EOIHandler, &mpu401_eoi_callback, &mpu401_eoi_callback, mpu);
    timer_add(MPU401_ResetDone, &mpu401_reset_callback, &mpu401_reset_callback, mpu);

    MPU401_Reset(mpu);
}


void
mpu401_device_add(void)
{
    char *n;

    if (!mpu401_standalone_enable) return;

    n = sound_card_get_internal_name(sound_card_current);
    if (n != NULL) {
	if (!strcmp(n, "ncraudio"))
		mca_version = 1;
	else
		mca_version = 0;

	if (!strcmp(n, "sb16") || !strcmp(n, "sbawe32") || !strcmp(n, "replysb16")) return;
    }

    if (mca_version)
	device_add(&mpu401_mca_device);
    else
	device_add(&mpu401_device);
}


static uint8_t
mpu401_mca_read(int port, void *p)
{
    mpu_t *mpu = (mpu_t *)p;

    return mpu->pos_regs[port & 7];
}


static void
mpu401_mca_write(int port, uint8_t val, void *p)
{
    mpu_t *mpu = (mpu_t *)p;
    uint16_t addr;

    if (port < 0x102)
	return;

    addr = (mpu->pos_regs[2] & 2) ? 0x0330 : 0x1330;

    port &= 7;

    mpu->pos_regs[port] = val;

    if (port == 2) {
	io_removehandler(addr, 2,
			 mpu401_read, NULL, NULL, mpu401_write, NULL, NULL, mpu);

	addr = (mpu->pos_regs[2] & 2) ? 0x1330 : 0x0330;

	io_sethandler(addr, 2,
		      mpu401_read, NULL, NULL, mpu401_write, NULL, NULL, mpu);
    }
}


static void *
mpu401_standalone_init(const device_t *info)
{
    mpu_t *mpu;
    int irq;
    uint16_t base;

    mpu = malloc(sizeof(mpu_t));
    memset(mpu, 0, sizeof(mpu_t));
 
    mpu401_log("mpu_init\n");

    if (info->flags & DEVICE_MCA) {
	mca_add(mpu401_mca_read, mpu401_mca_write, mpu);
	mpu->pos_regs[0] = 0x0F;
	mpu->pos_regs[1] = 0x6C;
	base = 0;	/* Tell mpu401_init() that this is the MCA variant. */
	irq = 2;	/* According to @6c0f.adf, the IRQ is fixed to 2. */
    } else {
	base = device_get_config_hex16("base");
	irq = device_get_config_int("irq");
    }

    mpu401_init(mpu, base, irq, M_INTELLIGENT);

    return(mpu);
}


static void
mpu401_standalone_close(void *priv)
{
    mpu_t *mpu = (mpu_t *)priv;

    free(mpu);
}


static const device_config_t mpu401_standalone_config[] =
{
        {
                "base", "MPU-401 Address", CONFIG_HEX16, "", 0x330,
                {
                        {
                                "0x300", 0x300
                        },
                        {
                                "0x330", 0x330
                        },
                        {
                                ""
                        }
                }
        },
        {
                "irq", "MPU-401 IRQ", CONFIG_SELECTION, "", 9,
                {
                        {
                                "IRQ 9", 9
                        },
                        {
                                "IRQ 3", 3
                        },
                        {
                                "IRQ 4", 4
                        },
                        {
                                "IRQ 5", 5
                        },
                        {
                                "IRQ 7", 7
                        },
                        {
                                "IRQ 10", 10
                        },
                        {
                                ""
                        }
                }
        },
        {
                "", "", -1
        }
};


const device_t mpu401_device = {
    "MPU-401 (Standalone)",
    DEVICE_ISA, 0,
    mpu401_standalone_init, mpu401_standalone_close, NULL,
    NULL,
    NULL,
    NULL,
    mpu401_standalone_config
};

const device_t mpu401_mca_device = {
    "Roland MPU-IMC",
    DEVICE_MCA, 0,
    mpu401_standalone_init, mpu401_standalone_close, NULL,
    NULL,
    NULL,
    NULL,
    NULL
};