third_party/ulib/musl/src/math/exp10l.c

#define _GNU_SOURCE
#include "libc.h"
#include "libm.h"
#include <float.h>
#include <math.h>

#if LDBL_MANT_DIG == 53 && LDBL_MAX_EXP == 1024
long double exp10l(long double x) {
    return exp10(x);
}
#elif (LDBL_MANT_DIG == 64 || LDBL_MANT_DIG == 113) && LDBL_MAX_EXP == 16384
long double exp10l(long double x) {
    static const long double p10[] = {1e-15L, 1e-14L, 1e-13L, 1e-12L, 1e-11L, 1e-10L, 1e-9L, 1e-8L,
                                      1e-7L, 1e-6L, 1e-5L, 1e-4L, 1e-3L, 1e-2L, 1e-1L, 1,
                                      1e1, 1e2, 1e3, 1e4, 1e5, 1e6, 1e7, 1e8,
                                      1e9, 1e10, 1e11, 1e12, 1e13, 1e14, 1e15};
    long double n, y = modfl(x, &n);
    union ldshape u = {n};
    /* fabsl(n) < 16 without raising invalid on nan */
    if ((u.i.se & 0x7fff) < 0x3fff + 4) {
        if (!y)
            return p10[(int)n + 15];
        y = exp2l(3.32192809488736234787031942948939L * y);
        return y * p10[(int)n + 15];
    }
    return powl(10.0, x);
}
#endif

weak_alias(exp10l, pow10l);