86Box/src/chipset/opti495.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.
 *
 *		Implementation of the OPTi 82C493/82C495 chipset.
 *
 *
 *
 * Authors:	Tiseno100,
 *		Miran Grca, <mgrca8@gmail.com>
 *
 *		Copyright 2008-2020 Tiseno100.
 *		Copyright 2016-2020 Miran Grca.
 */
#include <stdarg.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <wchar.h>
#define HAVE_STDARG_H
#include <86box/86box.h>
#include "cpu.h"
#include <86box/io.h>
#include <86box/device.h>
#include <86box/mem.h>
#include <86box/port_92.h>
#include <86box/chipset.h>


typedef struct
{
    uint8_t	idx,
		regs[256],
		scratch[2];
} opti495_t;


#ifdef ENABLE_OPTI495_LOG
int opti495_do_log = ENABLE_OPTI495_LOG;


static void
opti495_log(const char *fmt, ...)
{
    va_list ap;

    if (opti495_do_log) {
	va_start(ap, fmt);
	pclog_ex(fmt, ap);
	va_end(ap);
    }
}
#else
#define opti495_log(fmt, ...)
#endif


static void
opti495_recalc(opti495_t *dev)
{
    uint32_t base;
    uint32_t i, shflags = 0;

    shadowbios = 0;
    shadowbios_write = 0;

    if (dev->regs[0x22] & 0x80) {
	shadowbios = 1;
	shadowbios_write = 0;
	shflags = MEM_READ_EXTANY | MEM_WRITE_INTERNAL;
    } else {
	shadowbios = 0;
	shadowbios_write = 1;
	shflags = MEM_READ_INTERNAL | MEM_WRITE_DISABLED;
    }

    mem_set_mem_state_both(0xf0000, 0x10000, shflags);

    for (i = 0; i < 8; i++) {
	base = 0xd0000 + (i << 14);

	if ((dev->regs[0x22] & ((base >= 0xe0000) ? 0x20 : 0x40)) &&
	    (dev->regs[0x23] & (1 << i))) {
		shflags = MEM_READ_INTERNAL;
		shflags |= (dev->regs[0x22] & ((base >= 0xe0000) ? 0x08 : 0x10)) ? MEM_WRITE_DISABLED : MEM_WRITE_INTERNAL;
	} else {
		if (dev->regs[0x26] & 0x40) {
			shflags = MEM_READ_EXTANY;
			shflags |= (dev->regs[0x22] & ((base >= 0xe0000) ? 0x08 : 0x10)) ? MEM_WRITE_DISABLED : MEM_WRITE_INTERNAL;
		} else
			shflags = MEM_READ_EXTANY | MEM_WRITE_EXTANY;
	}

	mem_set_mem_state_both(base, 0x4000, shflags);
    }

    for (i = 0; i < 4; i++) {
	base = 0xc0000 + (i << 14);

	if ((dev->regs[0x26] & 0x10) && (dev->regs[0x26] & (1 << i))) {
		shflags = MEM_READ_INTERNAL;
		shflags |= (dev->regs[0x26] & 0x20) ? MEM_WRITE_DISABLED : MEM_WRITE_INTERNAL;
	} else {
		if (dev->regs[0x26] & 0x40) {
			shflags = MEM_READ_EXTANY;
			shflags |= (dev->regs[0x26] & 0x20) ? MEM_WRITE_DISABLED : MEM_WRITE_INTERNAL;
		} else
			shflags = MEM_READ_EXTANY | MEM_WRITE_EXTANY;
	}

	mem_set_mem_state_both(base, 0x4000, shflags);
    }

    flushmmucache();
}


static void
opti495_write(uint16_t addr, uint8_t val, void *priv)
{
    opti495_t *dev = (opti495_t *) priv;

    switch (addr) {
	case 0x22:
		opti495_log("[%04X:%08X] [W] dev->idx = %02X\n", CS, cpu_state.pc, val);
		dev->idx = val;
		break;
	case 0x24:
		if ((dev->idx >= 0x20) && (dev->idx <= 0x2d)) {
			dev->regs[dev->idx] = val;
			opti495_log("[%04X:%08X] [W] dev->regs[%04X] = %02X\n", CS, cpu_state.pc, dev->idx, val);

			switch(dev->idx) {
				case 0x21:
					cpu_cache_ext_enabled = !!(dev->regs[0x21] & 0x10);
					cpu_update_waitstates();
					break;

				case 0x22:
				case 0x23:
				case 0x26:
					opti495_recalc(dev);
					break;
			}
		}
		break;

	case 0xe1:
	case 0xe2:
		dev->scratch[~addr & 0x01] = val;
		break;
    }
}


static uint8_t
opti495_read(uint16_t addr, void *priv)
{
    uint8_t ret = 0xff;
    opti495_t *dev = (opti495_t *) priv;

    switch (addr) {
	case 0x22:
		opti495_log("[%04X:%08X] [R] dev->idx = %02X\n", CS, cpu_state.pc, ret);
		break;
	case 0x24:
		if ((dev->idx >= 0x20) && (dev->idx <= 0x2d)) {
			ret = dev->regs[dev->idx];
			opti495_log("[%04X:%08X] [R] dev->regs[%04X] = %02X\n", CS, cpu_state.pc, dev->idx, ret);
		}
		break;
	case 0xe1:
	case 0xe2:
		ret = dev->scratch[~addr & 0x01];
		break;
    }

    return ret;
}


static void
opti495_close(void *priv)
{
    opti495_t *dev = (opti495_t *) priv;

    free(dev);
}


static void *
opti495_init(const device_t *info)
{
    opti495_t *dev = (opti495_t *) malloc(sizeof(opti495_t));
    memset(dev, 0, sizeof(opti495_t));

    device_add(&port_92_device);

    io_sethandler(0x0022, 0x0001, opti495_read, NULL, NULL, opti495_write, NULL, NULL, dev);
    io_sethandler(0x0024, 0x0001, opti495_read, NULL, NULL, opti495_write, NULL, NULL, dev);

    dev->scratch[0] = dev->scratch[1] = 0xff;

    if (info->local == 1) {
	/* 85C495 */
	dev->regs[0x20] = 0x02;
	dev->regs[0x21] = 0x20;
	dev->regs[0x22] = 0xe4;
	dev->regs[0x25] = 0xf0;
	dev->regs[0x26] = 0x80;
	dev->regs[0x27] = 0xb1;
	dev->regs[0x28] = 0x80;
	dev->regs[0x29] = 0x10;
    } else {
	/* 85C493 */
	dev->regs[0x20] = 0x40;
	dev->regs[0x22] = 0x84;
	dev->regs[0x24] = 0x87;
	dev->regs[0x25] = 0xf1;		/* Note: 0xf0 is also valid default. */
	dev->regs[0x27] = 0x91;
	dev->regs[0x28] = 0x80;
	dev->regs[0x29] = 0x10;
	dev->regs[0x2a] = 0x80;
	dev->regs[0x2b] = 0x10;
    }

    opti495_recalc(dev);

    io_sethandler(0x00e1, 0x0002, opti495_read, NULL, NULL, opti495_write, NULL, NULL, dev);

    return dev;
}


const device_t opti493_device = {
    "OPTi 82C493",
    0,
    0,
    opti495_init, opti495_close, NULL,
    { NULL }, NULL, NULL,
    NULL
};


const device_t opti495_device = {
    "OPTi 82C495",
    0,
    1,
    opti495_init, opti495_close, NULL,
    { NULL }, NULL, NULL,
    NULL
};