1#include "libm.h" 2 3#if FLT_EVAL_METHOD == 0 4#define EPS FLT_EPSILON 5#elif FLT_EVAL_METHOD == 1 6#define EPS DBL_EPSILON 7#elif FLT_EVAL_METHOD == 2 8#define EPS LDBL_EPSILON 9#endif 10static const float_t toint = 1 / EPS; 11 12float roundf(float x) { 13 union { 14 float f; 15 uint32_t i; 16 } u = {x}; 17 int e = u.i >> 23 & 0xff; 18 float_t y; 19 20 if (e >= 0x7f + 23) 21 return x; 22 if (u.i >> 31) 23 x = -x; 24 if (e < 0x7f - 1) { 25 FORCE_EVAL(x + toint); 26 return 0 * u.f; 27 } 28 y = x + toint - toint - x; 29 if (y > 0.5f) 30 y = y + x - 1; 31 else if (y <= -0.5f) 32 y = y + x + 1; 33 else 34 y = y + x; 35 if (u.i >> 31) 36 y = -y; 37 return y; 38} 39