#include "libm.h" float nexttowardf(float x, long double y) { union {float f; uint32_t i;} ux = {x}; uint32_t e; if (isnan(x) || isnan(y)) return x + y; if (x == y) return y; if (x == 0) { ux.i = 1; if (signbit(y)) ux.i |= 0x80000000; } else if (x < y) { if (signbit(x)) ux.i--; else ux.i++; } else { if (signbit(x)) 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; }