sys.c

一款类linux的操作系统源码

/* 
 *  Roadrunner/pk
 *    Copyright (C) 1989-2001  Cornfed Systems, Inc.
 *
 *  The Roadrunner/pk operating system is free software; you can
 *  redistribute and/or modify it under the terms of the GNU General
 *  Public License, version 2, as published by the Free Software
 *  Foundation.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public
 *  License along with this program; if not, write to the Free
 *  Software Foundation, Inc., 59 Temple Place, Suite 330, Boston,
 *  MA 02111-1307 USA
 *
 *  More information about the Roadrunner/pk operating system of
 *  which this file is a part is available on the World-Wide Web
 *  at: http://www.cornfed.com.
 *
 */

//2002年10月10日big little endian 问题

#include <sys.h>

int
bcd2int(u_char v)
{
    return (int) ((v >> 4) * 10 + (v % 0x10));
}

u_char
loadbyte(u_char * ptr)
{
    return *ptr;
}

u_int
loadword(u_char * ptr)
{
    return (u_int)(* ptr << 8) | (u_int) *(ptr + 1) ;
}

u_int
loaddword(u_char * ptr)
{
    return (u_int) (*ptr <<24) |
	(u_int) (*(ptr + 1) << 16) |
	(u_int) (*(ptr + 2) << 8 ) | (u_int) *(ptr + 3);
}

void
storebyte(u_char val, u_char * ptr)
{
    *ptr = (u_char) val & 0xff;
}

void
storeword(u_int val, u_char * ptr)
{
    *ptr = (u_char) (val >> 8) & 0xff;
    *(ptr + 1) = (u_char) val & 0xff;
}

void
storedword(u_int val, u_char * ptr)
{
    *ptr =  (u_char) (val >> 24) & 0xff;
    *(ptr + 1) = (u_char) (val >> 16) & 0xff;
    *(ptr + 2) = (u_char) (val >> 8) & 0xff;
    *(ptr + 3) = (u_char) val & 0xff;
}