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

#include "libm.h"

#if LDBL_MANT_DIG == 53 && LDBL_MAX_EXP == 1024
long double truncl(long double x) {
    return trunc(x);
}
#elif (LDBL_MANT_DIG == 64 || LDBL_MANT_DIG == 113) && LDBL_MAX_EXP == 16384

static const long double toint = 1 / LDBL_EPSILON;

long double truncl(long double x) {
    union ldshape u = {x};
    int e = u.i.se & 0x7fff;
    int s = u.i.se >> 15;
    long double y;

    if (e >= 0x3fff + LDBL_MANT_DIG - 1)
        return x;
    if (e <= 0x3fff - 1) {
        FORCE_EVAL(x + 0x1p120f);
        return x * 0;
    }
    /* y = int(|x|) - |x|, where int(|x|) is an integer neighbor of |x| */
    if (s)
        x = -x;
    y = x + toint - toint - x;
    if (y > 0)
        y -= 1;
    x += y;
    return s ? -x : x;
}
#endif