a505894a10
- 86Box's own headers go to /86box - munt's public interface goes to /mt32emu - all slirp headers go to /slirp (might want to consider using only its public inteface) - single file headers from other projects go in include root
134 lines
2.5 KiB
C
134 lines
2.5 KiB
C
/*
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* 86Box A hypervisor and IBM PC system emulator that specializes in
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* running old operating systems and software designed for IBM
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* PC systems and compatibles from 1981 through fairly recent
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* system designs based on the PCI bus.
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*
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* This file is part of the 86Box distribution.
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*
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* ICS2595 clock chip emulation. Used by ATI Mach64.
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*
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*
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*
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* Authors: Sarah Walker, <http://pcem-emulator.co.uk/>
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* Miran Grca, <mgrca8@gmail.com>
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*
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* Copyright 2008-2018 Sarah Walker.
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* Copyright 2016-2018 Miran Grca.
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*/
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#include <stdio.h>
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#include <stdint.h>
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#include <stdlib.h>
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#include <string.h>
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#include <wchar.h>
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#include <86box/86box.h>
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#include <86box/device.h>
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typedef struct ics2595_t
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{
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int oldfs3, oldfs2;
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int dat;
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int pos, state;
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double clocks[16];
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double output_clock;
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} ics2595_t;
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enum
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{
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ICS2595_IDLE = 0,
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ICS2595_WRITE,
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ICS2595_READ
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};
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static int ics2595_div[4] = {8, 4, 2, 1};
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void
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ics2595_write(void *p, int strobe, int dat)
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{
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ics2595_t *ics2595 = (ics2595_t *) p;
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int d, n;
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int l;
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if (strobe) {
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if ((dat & 8) && !ics2595->oldfs3) { /*Data clock*/
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switch (ics2595->state) {
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case ICS2595_IDLE:
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ics2595->state = (dat & 4) ? ICS2595_WRITE : ICS2595_IDLE;
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ics2595->pos = 0;
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break;
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case ICS2595_WRITE:
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ics2595->dat = (ics2595->dat >> 1);
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if (dat & 4)
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ics2595->dat |= (1 << 19);
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ics2595->pos++;
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if (ics2595->pos == 20) {
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l = (ics2595->dat >> 2) & 0xf;
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n = ((ics2595->dat >> 7) & 255) + 257;
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d = ics2595_div[(ics2595->dat >> 16) & 3];
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ics2595->clocks[l] = (14318181.8 * ((double)n / 46.0)) / (double)d;
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ics2595->state = ICS2595_IDLE;
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}
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break;
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}
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}
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ics2595->oldfs2 = dat & 4;
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ics2595->oldfs3 = dat & 8;
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}
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ics2595->output_clock = ics2595->clocks[dat];
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}
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static void *
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ics2595_init(const device_t *info)
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{
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ics2595_t *ics2595 = (ics2595_t *) malloc(sizeof(ics2595_t));
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memset(ics2595, 0, sizeof(ics2595_t));
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return ics2595;
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}
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static void
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ics2595_close(void *priv)
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{
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ics2595_t *ics2595 = (ics2595_t *) priv;
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if (ics2595)
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free(ics2595);
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}
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double
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ics2595_getclock(void *p)
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{
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ics2595_t *ics2595 = (ics2595_t *) p;
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return ics2595->output_clock;
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}
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void
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ics2595_setclock(void *p, double clock)
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{
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ics2595_t *ics2595 = (ics2595_t *) p;
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ics2595->output_clock = clock;
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}
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const device_t ics2595_device =
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{
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"ICS2595 clock chip",
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0, 0,
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ics2595_init, ics2595_close,
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NULL, NULL, NULL, NULL
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};
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