78 lines
1.6 KiB
C
78 lines
1.6 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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* CRC implementation.
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*
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* Authors: Miran Grca, <mgrca8@gmail.com>
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*
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* Copyright 2016-2025 Miran Grca.
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*/
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#include <stdint.h>
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#include <stdio.h>
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#include <string.h>
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#include <stdlib.h>
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#include <stdarg.h>
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#include <assert.h>
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#include <wchar.h>
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#define HAVE_STDARG_H
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#include <86box/86box.h>
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#include <86box/timer.h>
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#include <86box/dma.h>
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#include <86box/nvr.h>
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#include <86box/random.h>
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#include <86box/plat.h>
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#include <86box/ui.h>
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#include <86box/crc.h>
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#ifdef ENABLE_CRC_LOG
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int d86f_do_log = ENABLE_CRC_LOG;
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static void
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crc_log(const char *fmt, ...)
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{
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va_list ap;
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if (crc_do_log) {
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va_start(ap, fmt);
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pclog_ex(fmt, ap);
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va_end(ap);
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}
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}
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#else
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# define crc_log(fmt, ...)
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#endif
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void
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crc16_setup(uint16_t *crc_table, uint16_t poly)
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{
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int c = 256;
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int bc;
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uint16_t temp;
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while (c--) {
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temp = c << 8;
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bc = 8;
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while (bc--) {
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if (temp & 0x8000)
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temp = (temp << 1) ^ poly;
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else
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temp <<= 1;
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crc_table[c] = temp;
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}
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}
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}
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void
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crc16_calc(uint16_t *crc_table, uint8_t byte, crc_t *crc_var)
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{
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crc_var->word = (crc_var->word << 8) ^
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crc_table[(crc_var->word >> 8) ^ byte];
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}
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