payloads/libpayload/libc/lib.c

   1 /*
   2  * This file is part of the libpayload project.
   3  *
   4  * Copyright (C) 2008 Uwe Hermann <uwe@hermann-uwe.de>
   5  *
   6  * Redistribution and use in source and binary forms, with or without
   7  * modification, are permitted provided that the following conditions
   8  * are met:
   9  * 1. Redistributions of source code must retain the above copyright
  10  *    notice, this list of conditions and the following disclaimer.
  11  * 2. Redistributions in binary form must reproduce the above copyright
  12  *    notice, this list of conditions and the following disclaimer in the
  13  *    documentation and/or other materials provided with the distribution.
  14  * 3. The name of the author may not be used to endorse or promote products
  15  *    derived from this software without specific prior written permission.
  16  *
  17  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
  18  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  19  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  20  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
  21  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  22  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  23  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  24  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  25  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  26  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  27  * SUCH DAMAGE.
  28  */
  29
  30 #include <libpayload.h>
  31
  32 /*
  33  * Convert a number in BCD format to decimal.
  34  *
  35  * @param b The BCD number.
  36  * @return The given BCD number in decimal format.
  37  */
  38 int bcd2dec(int b)
  39 {
  40         return ((b >> 4) & 0x0f) * 10 + (b & 0x0f);
  41 }
  42
  43 /*
  44  * Convert a number in decimal format into the BCD format.
  45  *
  46  * @param d The decimal number.
  47  * @return The given decimal number in BCD format.
  48  */
  49 int dec2bcd(int d)
  50 {
  51         return ((d / 10) << 4) | (d % 10);
  52 }
  53
  54 /**
  55  * Return the absolute value of the specified integer.
  56  *
  57  * @param j The integer of which we want to know the absolute value.
  58  * @return The absolute value of the specified integer.
  59  */
  60 int abs(int j)
  61 {
  62         return (j >= 0 ? j : -j);
  63 }
  64
  65 long int labs(long int j)
  66 {
  67         return (j >= 0 ? j : -j);
  68 }
  69
  70 long long int llabs(long long int j)
  71 {
  72         return (j >= 0 ? j : -j);
  73 }
  74
  75 /**
  76  * Given a 4-bit value, return the ASCII hex representation of it.
  77  *
  78  * @param b A 4-bit value which shall be converted to ASCII hex.
  79  * @return The ASCII hex representation of the specified 4-bit value.
  80  *         Returned hex-characters will always be lower-case (a-f, not A-F).
  81  */
  82 u8 bin2hex(u8 b)
  83 {
  84         return (b < 10) ? '0' + b : 'a' + (b - 10);
  85 }
  86
  87 /**
  88  * Given an ASCII hex input character, return its integer value.
  89  *
  90  * For example, the input value '6' will be converted to 6, 'a'/'A' will
  91  * be converted to 10, 'f'/'F' will be converted to 15, and so on.
  92  *
  93  * The return value for invalid input characters is 0.
  94  *
  95  * @param h The input byte in ASCII hex format.
  96  * @return The integer value of the specified ASCII hex byte.
  97  */
  98 u8 hex2bin(u8 h)
  99 {
 100         return (('0' <= h && h <= '9') ? (h - '0') : \
 101                 ('A' <= h && h <= 'F') ? (h - 'A' + 10) : \
 102                 ('a' <= h && h <= 'f') ? (h - 'a' + 10) : 0);
 103 }
 104
 105 /**
 106  * Enters HALT state, after printing msg
 107  *
 108  * @param msg message to print
 109  */
 110 void fatal(const char *msg)
 111 {
 112         fprintf(stderr, "%s",msg);
 113         halt();
 114 }
 115
 116 void exit(int status)
 117 {
 118         printf("exited with status %d\n", status);
 119         halt();
 120 }
 121
 122 int errno;
 123
 124 char *getenv(const char *name)
 125 {
 126         return NULL;
 127 }