sli.c

00001 /*
00002 # This file is Copyright 2003, 2006, 2007, 2009 Dean Hall.
00003 #
00004 # This file is part of the PyMite VM.
00005 # The PyMite VM is free software: you can redistribute it and/or modify
00006 # it under the terms of the GNU GENERAL PUBLIC LICENSE Version 2.
00007 #
00008 # The PyMite VM is distributed in the hope that it will be useful,
00009 # but WITHOUT ANY WARRANTY; without even the implied warranty of
00010 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
00011 # A copy of the GNU GENERAL PUBLIC LICENSE Version 2
00012 # is seen in the file COPYING in this directory.
00013 */
00014 
00015 
00016 #undef __FILE_ID__
00017 #define __FILE_ID__ 0x11
00018 
00019 
00020 /**
00021  * \file
00022  * \brief Standard Library Interface
00023  *
00024  * PyMite requires a few functions from a few different
00025  * standard C libraries (memory, string, etc).
00026  */
00027 
00028 
00029 #include "pm.h"
00030 
00031 
00032 /** use Duff's Device or simple for-loop for memcpy. */
00033 #define USE_DUFFS_DEVICE    0
00034 
00035 
00036 #if !HAVE_STRING_H
00037 
00038 void *
00039 sli_memcpy(unsigned char *to, unsigned char const *from, unsigned int n)
00040 {
00041     unsigned char *tobak;
00042 
00043     /* Store init value of to */
00044     tobak = to;
00045 
00046 #if USE_DUFFS_DEVICE
00047     if (n > 0)
00048     {
00049         switch (n & 0x7)
00050             do
00051             {
00052             case 0:
00053                 *to++ = *from++;
00054             case 7:
00055                 *to++ = *from++;
00056             case 6:
00057                 *to++ = *from++;
00058             case 5:
00059                 *to++ = *from++;
00060             case 4:
00061                 *to++ = *from++;
00062             case 3:
00063                 *to++ = *from++;
00064             case 2:
00065                 *to++ = *from++;
00066             case 1:
00067                 *to++ = *from++;
00068             }
00069             while ((n -= 8) > 0);
00070     }
00071 #else
00072     for (; n > 0; n--)
00073     {
00074         *to = *from;
00075         from++;
00076         to++;
00077     }
00078 #endif /* USE_DUFFS_DEVICE */
00079     return tobak;
00080 }
00081 
00082 
00083 int
00084 sli_strlen(char const *s)
00085 {
00086     char const *si = s;
00087     int len = 0;
00088 
00089     while (*si++)
00090     {
00091         len++;
00092     }
00093     return len;
00094 }
00095 
00096 
00097 int
00098 sli_strcmp(char const *s1, char const *s2)
00099 {
00100     /* While not at either strings' end and they're same */
00101     while ((*s1 != C_NULL) && (*s2 != C_NULL) && (*s1 == *s2))
00102     {
00103         s1++;
00104         s2++;
00105     }
00106 
00107     /* Return string difference */
00108     return *s1 - *s2;
00109 }
00110 
00111 
00112 int
00113 sli_strncmp(char const *s1, char const *s2, unsigned int n)
00114 {
00115     unsigned int i = 0;
00116 
00117     if (n == 0)
00118     {
00119         return 0;
00120     }
00121 
00122     /* Scan n bytes in string */
00123     for (i = 0; i < n; i++)
00124     {
00125         /* If bytes differ, return difference */
00126         if (s1[i] != s2[i])
00127         {
00128             return s1[i] - s2[i];
00129         }
00130     }
00131     return 0;
00132 }
00133 
00134 #endif /* HAVE_STRING_H */
00135 
00136 
00137 /*
00138  * This function is moved outside of HAVE_STRING_H because the one in string.h
00139  * will not accept a null value for the second arg
00140  */
00141 void
00142 sli_memset(unsigned char *dest, char const val, unsigned int n)
00143 {
00144     unsigned int i;
00145 
00146     for (i = 0; i < n; i++)
00147     {
00148         *dest = (unsigned char)val;
00149         dest++;
00150     }
00151 }