source: azure_iot_hub/trunk/musl-1.1.18/src/math/nextafterf.c@ 389

#include "libm.h"

float nextafterf(float x, float y)
{
        union {float f; uint32_t i;} ux={x}, uy={y};
        uint32_t ax, ay, e;

        if (isnan(x) || isnan(y))
                return x + y;
        if (ux.i == uy.i)
                return y;
        ax = ux.i & 0x7fffffff;
        ay = uy.i & 0x7fffffff;
        if (ax == 0) {
                if (ay == 0)
                        return y;
                ux.i = (uy.i & 0x80000000) | 1;
        } else if (ax > ay || ((ux.i ^ uy.i) & 0x80000000))
                ux.i--;
        else
                ux.i++;
        e = ux.i & 0x7f800000;
        /* raise overflow if ux.f is infinite and x is finite */
        if (e == 0x7f800000)
                FORCE_EVAL(x+x);
        /* raise underflow if ux.f is subnormal or zero */
        if (e == 0)
                FORCE_EVAL(x*x + ux.f*ux.f);
        return ux.f;
}