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/* Project:     OSLib
 * Description: The OS Construction Kit
 * Date:                1.6.2000
 * Idea by:             Luca Abeni & Gerardo Lamastra
 *
 * OSLib is an SO project aimed at developing a common, easy-to-use
 * low-level infrastructure for developing OS kernels and Embedded
 * Applications; it partially derives from the HARTIK project but it
 * currently is independently developed.
 *
 * OSLib is distributed under GPL License, and some of its code has
 * been derived from the Linux kernel source; also some important
 * ideas come from studying the DJGPP go32 extender.
 *
 * We acknowledge the Linux Community, Free Software Foundation,
 * D.J. Delorie and all the other developers who believe in the
 * freedom of software and ideas.
 *
 * For legalese, check out the included GPL license.
 */

#include <arch/i386/stdlib.h>
#include <arch/i386/string.h>
#include <arch/i386/limits.h>
#include <arch/stdarg.h>
#include <arch/ctype.h>
#include <arch/math.h>

FILE(strod);

double strtod(char *s,char **scan_end)
{
    int sign,i;
    double result = 0;
    double value;
    double mantissa = 0,divisor = 1;
    unsigned short power = 0;
    /* Evaluate sign */
    if (*s == '-') {
        sign = -1;
        s++;
    }
    else sign = 1;
    /* Skip trailing zeros */
    while (*s == '0') s++;
    /* Convert integer part */
    while (*s <= '9' && *s >= '0') {
        value = *s++ - '0';
        result *= 10.0;
        result += value;
    }
    /* Detect floating point & mantissa */
    if (*s == '.') {
        s++;
        while (*s <= '9' && *s >= '0') {
            value = *s++ - '0';
            mantissa *= 10.0;
            mantissa += value;
            divisor *= 10.0;
        }
    }
    mantissa /= divisor;
    /* Adjust result */
    result += mantissa;
    /* Adjust sign */
    result *= sign;
    /* Detect exponent */
    if (*s == 'e' || *s == 'E') {
        s++;
        if (*s == '-') {
            sign = -1;
            s++;
        } else if (*s == '+') {
            sign = 1;
            s++;
        }
        else sign = 1;
        while (*s <= '9' && *s >= '0') {
            value = *s++ - '0';
            power *= 10.0;
            power += value;
        }
    }
    /* Adjust result on exponent sign */
    if (sign > 0) for (i = 0; i < power; i++) result *= 10.0;
    else for (i = 0; i < power; i++) result /= 10.0;
    if (scan_end != 0L) *scan_end = s;
    return(result);
}