158 lines
3.6 KiB
C
158 lines
3.6 KiB
C
/*
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* VARCem Virtual Archaelogical Computer EMulator.
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* An emulator of (mostly) x86-based PC systems and devices,
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* using the ISA,EISA,VLB,MCA and PCI system buses, roughly
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* spanning the era between 1981 and 1995.
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*
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* This file is part of the VARCem Project.
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*
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* Intel 82335 SX emulation, used by the Phoenix 386 clone.
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*
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* Version: @(#)i82335.c 1.0.1 2018/02/14
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*
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* Authors: Fred N. van Kempen, <decwiz@yahoo.com>
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* Miran Grca, <mgrca8@gmail.com>
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* Sarah Walker, <tommowalker@tommowalker.co.uk>
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*
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* Copyright 2017,2018 Fred N. van Kempen.
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* Copyright 2016-2018 Miran Grca.
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* Copyright 2008-2018 Sarah Walker.
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the:
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*
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* Free Software Foundation, Inc.
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* 59 Temple Place - Suite 330
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* Boston, MA 02111-1307
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* USA.
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*/
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#include <stdio.h>
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#include <stdint.h>
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#include <string.h>
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#include <wchar.h>
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#include "io.h"
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#include "mem.h"
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typedef struct {
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uint8_t reg_22;
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uint8_t reg_23;
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} i82335_t;
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static i82335_t i82335;
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static uint8_t
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i82335_read(uint16_t addr, void *priv)
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{
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// pclog("i82335_read(%04X)\n", addr);
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if (addr == 0x22) {
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return(i82335.reg_22);
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}
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if (addr == 0x23) {
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return(i82335.reg_23);
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}
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return(0);
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}
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static void
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i82335_write(uint16_t addr, uint8_t val, void *priv)
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{
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int mem_write = 0;
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int i = 0;
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// pclog("i82335_write(%04X, %02X)\n", addr, val);
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switch (addr) {
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case 0x22:
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if ((val ^ i82335.reg_22) & 1) {
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if (val & 1) {
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for (i=0; i<8; i++) {
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mem_set_mem_state(0xe0000, 0x20000, MEM_READ_INTERNAL | MEM_WRITE_INTERNAL);
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shadowbios = 1;
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}
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} else {
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for (i=0; i<8; i++) {
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mem_set_mem_state(0xe0000, 0x20000, MEM_READ_EXTERNAL | MEM_WRITE_EXTERNAL);
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shadowbios = 0;
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}
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}
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flushmmucache();
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}
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i82335.reg_22 = val | 0xd8;
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break;
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case 0x23:
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i82335.reg_23 = val;
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if ((val ^ i82335.reg_22) & 2) {
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if (val & 2) {
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for (i=0; i<8; i++) {
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mem_set_mem_state(0xc0000, 0x20000, MEM_READ_INTERNAL | MEM_WRITE_INTERNAL);
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shadowbios = 1;
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}
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} else {
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for (i=0; i<8; i++) {
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mem_set_mem_state(0xc0000, 0x20000, MEM_READ_EXTERNAL | MEM_WRITE_EXTERNAL);
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shadowbios = 0;
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}
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}
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}
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if ((val ^ i82335.reg_22) & 0xc) {
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if (val & 2) {
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for (i = 0; i < 8; i++) {
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mem_write = (val & 8) ? MEM_WRITE_DISABLED : MEM_WRITE_INTERNAL;
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mem_set_mem_state(0xa0000, 0x20000, MEM_READ_INTERNAL | mem_write);
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shadowbios = 1;
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}
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} else {
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for (i = 0; i < 8; i++) {
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mem_write = (val & 8) ? MEM_WRITE_DISABLED : MEM_WRITE_EXTERNAL;
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mem_set_mem_state(0xa0000, 0x20000, MEM_READ_EXTERNAL | mem_write);
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shadowbios = 0;
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}
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}
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}
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if ((val ^ i82335.reg_22) & 0xe) {
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flushmmucache();
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}
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if (val & 0x80) {
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io_removehandler(0x0022, 1,
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i82335_read,NULL,NULL,
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i82335_write,NULL,NULL, NULL);
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}
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break;
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}
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}
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void
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i82335_init(void)
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{
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memset(&i82335, 0x00, sizeof(i82335_t));
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i82335.reg_22 = 0xd8;
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io_sethandler(0x0022, 20,
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i82335_read,NULL,NULL, i82335_write,NULL,NULL, NULL);
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}
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