src/libc/stdlib.c

Go to the documentation of this file.

#include "tm_macros.h"
#include "libc_internal.h"
#include "tm_macros.h"
#include <ctype.h>


int
txc_libc_atoi(char *p)
{
        int n, f;

    TM_BEGIN
        n = 0;
        f = 0;
        for(;;p++) {
                switch(*p) {
                        case ' ':
                        case '\t':
                                continue;
                        case '-':
                                f++;
                        case '+':
                                p++;
                }
                break;
        }
        while(*p >= '0' && *p <= '9')
                n = n*10 + *p++ - '0';
        return(f? -n: n);
        TM_END
}

TM_WAIVER
int txc_libc_isdigit(int c)
{
        return isdigit(c);
}

double
txc_libc_atof(char *p)
{
        register c;
        double fl, flexp, exp5;
        double big = 72057594037927936.;  /*2^56*/
        double ldexp();
        int nd;
        register eexp, exp, neg, negexp, bexp;

    TM_BEGIN
        neg = 1;
        while((c = *p++) == ' ')
                ;
        if (c == '-')
                neg = -1;
        else if (c=='+')
                ;
        else
                --p;

        exp = 0;
        fl = 0;
        nd = 0;
        while ((c = *p++), txc_libc_isdigit(c)) {
                if (fl<big)
                        fl = 10*fl + (c-'0');
                else
                        exp++;
                nd++;
        }

        if (c == '.') {
                while ((c = *p++), txc_libc_isdigit(c)) {
                        if (fl<big) {
                                fl = 10*fl + (c-'0');
                                exp--;
                        }
                nd++;
                }
        }

        negexp = 1;
        eexp = 0;
        if ((c == 'E') || (c == 'e')) {
                if ((c= *p++) == '+')
                        ;
                else if (c=='-')
                        negexp = -1;
                else
                        --p;

                while ((c = *p++), txc_libc_isdigit(c)) {
                        eexp = 10*eexp+(c-'0');
                }
                if (negexp<0)
                        eexp = -eexp;
                exp = exp + eexp;
        }

        negexp = 1;
        if (exp<0) {
                negexp = -1;
                exp = -exp;
        }


        if((nd+exp*negexp) < -LOGHUGE){
                fl = 0;
                exp = 0;
        }
        flexp = 1;
        exp5 = 5;
        bexp = exp;
        for (;;) {
                if (exp&01)
                        flexp *= exp5;
                exp >>= 1;
                if (exp==0)
                        break;
                exp5 *= exp5;
        }
        if (negexp<0)
                fl /= flexp;
        else
                fl *= flexp;
        fl = ldexp(fl, negexp*bexp);
        if (neg<0)
                fl = -fl;
        return(fl);
        TM_END
}

---