119 lines
3 KiB
C++
119 lines
3 KiB
C++
/*
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* Copyright (C) 2002 The DOSBox Team
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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,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU Library 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 Free Software
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* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
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*/
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#include "dosbox.h"
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#include "timer.h"
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#include "pic.h"
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#include "inout.h"
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#include "config.h"
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static struct {
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Bit8u regs[0x40];
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bool nmi;
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Bit8u reg;
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struct {
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bool enabled;
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Bit8u div;
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Bitu micro;
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} timer;
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Bit8u status_c;
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bool ack;
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bool update_ended;
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} cmos;
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static void cmos_timerevent(void) {
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PIC_ActivateIRQ(8);
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if (cmos.ack) {
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PIC_AddEvent(cmos_timerevent,cmos.timer.micro);
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cmos.status_c=0x20;
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cmos.ack=false;
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}
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}
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static void cmos_checktimer(void) {
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PIC_RemoveEvents(cmos_timerevent);
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if (!cmos.timer.div && !cmos.timer.enabled) return;
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if (cmos.timer.div<=2) cmos.timer.div+=7;
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cmos.timer.micro=(Bitu) (10000000.0/(32768.0 / (1 << (cmos.timer.div - 1))));
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LOG_DEBUG("RTC Timer at %f hz",1000000.0/cmos.timer.micro);
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PIC_AddEvent(cmos_timerevent,cmos.timer.micro);
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}
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void cmos_selreg(Bit32u port,Bit8u val) {
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cmos.reg=val & 0x3f;
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cmos.nmi=(val & 0x80)>0;
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}
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static void cmos_writereg(Bit32u port,Bit8u val) {
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switch (cmos.reg) {
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case 0x00: /* Seconds */
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case 0x01: /* Seconds Alarm */
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case 0x02: /* Minutes */
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case 0x03: /* Minutes Alarm */
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case 0x04: /* Hours */
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case 0x05: /* Hours Alarm */
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case 0x06: /* Day of week */
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case 0x07: /* Date of month */
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case 0x08: /* Month */
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case 0x09: /* Year */
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cmos.regs[cmos.reg]=val;
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break;
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case 0x0a: /* Status reg A */
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cmos.regs[cmos.reg]=val & 0x7f;
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if (val & 0x70!=0x20) LOG_DEBUG("CMOS Illegal 22 stage divider value");
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cmos.timer.div=(val & 0xf);
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cmos_checktimer();
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break;
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case 0x0b: /* Status reg B */
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cmos.regs[cmos.reg]=val & 0x7f;
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cmos.timer.enabled=(val & 0x40)>0;
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if (val&0x10) LOG_DEBUG("CMOS:Updated ended interrupt not supported yet");
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cmos_checktimer();
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break;
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default:
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cmos.regs[cmos.reg]=val & 0x7f;
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LOG_DEBUG("CMOS:Unhandled register %x",cmos.reg);
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}
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}
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static Bit8u cmos_readreg(Bit32u port) {
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if (cmos.reg>0x3f) {
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LOG_DEBUG("CMOS:Read from illegal register %x",cmos.reg);
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return 0xff;
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}
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switch (cmos.reg) {
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case 0x0c:
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if (cmos.ack) return 0;
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else {
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cmos.ack=true;
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return 0x80|cmos.status_c;
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}
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default:
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return cmos.regs[cmos.reg];
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}
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}
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void CMOS_Init(Section* sec) {
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IO_RegisterWriteHandler(0x70,cmos_selreg,"CMOS");
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IO_RegisterWriteHandler(0x71,cmos_writereg,"CMOS");
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IO_RegisterReadHandler(0x71,cmos_readreg,"CMOS");
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cmos.timer.enabled=false;
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}
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