#include "libm.h"

float modff(float x, float* iptr) {
    union {
        float f;
        uint32_t i;
    } u = {x};
    uint32_t mask;
    int e = (int)(u.i >> 23 & 0xff) - 0x7f;

    /* no fractional part */
    if (e >= 23) {
        *iptr = x;
        if (e == 0x80 && u.i << 9 != 0) { /* nan */
            return x;
        }
        u.i &= 0x80000000;
        return u.f;
    }
    /* no integral part */
    if (e < 0) {
        u.i &= 0x80000000;
        *iptr = u.f;
        return x;
    }

    mask = 0x007fffff >> e;
    if ((u.i & mask) == 0) {
        *iptr = x;
        u.i &= 0x80000000;
        return u.f;
    }
    u.i &= ~mask;
    *iptr = u.f;
    return x - u.f;
}