fcs.h

ppp拨号程序源代码采用atmel芯片c语言编

/*
 * Copyright (C) 2003-2004 by Clive Moss. Email [e-mail] All rights reserved.
 *
 * Help & Contributions from D.J.Armstrong Email [e-mail]
 
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the name of the copyright holders nor the names of
 *    contributors may be used to endorse or promote products derived
 *    from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY CLIVE MOSS 'AS IS' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.
 * IN NO EVENT SHALL CLIVE MOSS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
 * INDIRECT, INCIDENTAL,SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
 * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
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 * THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#ifndef fcsH
#define fcsH

#include "common.h"

#define USB_INIT_FCS_16			0xffff		// Initial 16-bit FCS value

#define HDLC_PPP_INIT_FCS_16	0xffff		// Initial 16-bit FCS value
#define PPP_INIT_FCS_32			0xffffffff	// Initial 32-bit FCS value

#define HDLC_PPP_Polynomial_16	0x8408		// HDLC polynomial: x**0 + x**5 + x**12 + x**16
#define Modem_Polynomial		0x8005		// Modem polynomial: x**0 + x**5 + x**12
#define ZModem_PolyNominal		0xEDB88320	// Z-Modem polyNominal

extern u16 UpdateFCS_16(u16 fcs, u8 c);
extern u32 UpdateFCS_32(u32 fcs, u8 c);

#endif