117 lines
2.8 KiB
C
117 lines
2.8 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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* ICD2061 clock generator emulation.
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*
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* Used by ET4000w32/p (Diamond Stealth 32)
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*
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* Version: @(#)vid_icd2061.c 1.0.6 2018/10/02
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*
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* Authors: Miran Grca, <mgrca8@gmail.com>
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*
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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 <string.h>
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#include <wchar.h>
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#include "../86box.h"
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#include "vid_icd2061.h"
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void
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icd2061_write(icd2061_t *icd2061, int val)
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{
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int /*od, */nd, oc, nc;
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int a/*, i*/, qa, q, pa, p, m;
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#if 0
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od = (icd2061->state & 2) >> 1; /* Old data. */
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#endif
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nd = (val & 2) >> 1; /* Old data. */
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oc = icd2061->state & 1; /* Old clock. */
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nc = val & 1; /* New clock. */
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icd2061->state = val;
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if (nc && !oc) { /* Low-to-high transition of CLK. */
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if (!icd2061->unlocked) {
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if (nd) { /* DATA high. */
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icd2061->count++;
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/* pclog("Low-to-high transition of CLK with DATA high, %i total\n", icd2061->count); */
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} else { /* DATA low. */
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if (icd2061->count >= 5) {
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icd2061->unlocked = 1;
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icd2061->bit_count = icd2061->data = 0;
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/* pclog("ICD2061 unlocked\n"); */
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} else {
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icd2061->count = 0;
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/* pclog("ICD2061 locked\n"); */
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}
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}
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} else if (nc) {
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icd2061->data |= (nd << icd2061->bit_count);
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icd2061->bit_count++;
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if (icd2061->bit_count == 26) {
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/* pclog("26 bits received, data = %08X\n", icd2061->data); */
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a = ((icd2061->data >> 22) & 0x07); /* A */
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/* pclog("A = %01X\n", a); */
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if (a < 3) {
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#if 0
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i = ((icd2061->data >> 18) & 0x0f); /* I */
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#endif
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pa = ((icd2061->data >> 11) & 0x7f); /* P' */
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m = ((icd2061->data >> 8) & 0x07); /* M */
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qa = ((icd2061->data >> 1) & 0x7f); /* Q' */
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p = pa + 3; /* P */
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m = 1 << m;
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q = qa + 2; /* Q */
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if (icd2061->ctrl & (1 << a))
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p <<= 1;
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icd2061->freq[a] = ((float)p / (float)q) * 2.0 * 14318184.0 / (float)m;
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/* pclog("P = %02X, M = %01X, Q = %02X, freq[%i] = %f\n", p, m, q, a, icd2061->freq[a]); */
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} else if (a == 6) {
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icd2061->ctrl = ((icd2061->data >> 13) & 0xff);
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/* pclog("ctrl = %02X\n", icd2061->ctrl); */
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}
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icd2061->count = icd2061->bit_count = icd2061->data = 0;
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icd2061->unlocked = 0;
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/* pclog("ICD2061 locked\n"); */
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}
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}
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}
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}
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void
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icd2061_init(icd2061_t *icd2061)
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{
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memset(icd2061, 0, sizeof(icd2061_t));
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icd2061->freq[0] = 25175000.0;
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icd2061->freq[1] = 28322000.0;
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icd2061->freq[2] = 28322000.0;
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}
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float
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icd2061_getclock(int clock, void *p)
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{
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icd2061_t *icd2061 = (icd2061_t *) p;
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if (clock > 2)
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clock = 2;
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return icd2061->freq[clock];
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}
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