openblt

a hobby OS from the late 90s
git clone http://frotz.net/git/openblt.git
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stdlib.c (1804B)


      1 /* $Id: //depot/blt/lib/libc/stdlib.c#1 $
      2 **
      3 ** Copyright 1999 Sidney Cammeresi
      4 ** All rights reserved.
      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 ``AS IS'' AND ANY EXPRESS OR
     18 ** IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
     19 ** OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
     20 ** IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
     21 ** INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
     22 ** NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
     23 ** DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
     24 ** THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
     25 ** (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
     26 ** THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
     27 */
     28 
     29 #include <stdlib.h>
     30 #include <string.h>
     31 #include <blt/libsyms.h>
     32 
     33 weak_alias (_atoi, atoi)
     34 
     35 int _atoi (const char *a)
     36 {
     37 	int x, i, power = 1;
     38 
     39 	for (x = strlen (a) - 1, i = 0; x >= 0; x--, power *= 10)
     40 		if (!x && (a[x] == '-'))
     41 			i *= -1;
     42 		else
     43 			i += power * (a[x] - '0');
     44 	return i;
     45 }
     46