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 10 static const float_t toint = 1/EPS; 11 roundf(float x)12float roundf(float x) 13 { 14 union {float f; uint32_t i;} u = {x}; 15 int e = u.i >> 23 & 0xff; 16 float_t y; 17 18 if (e >= 0x7f+23) 19 return x; 20 if (u.i >> 31) 21 x = -x; 22 if (e < 0x7f-1) { 23 FORCE_EVAL(x + toint); 24 return 0*u.f; 25 } 26 y = x + toint - toint - x; 27 if (y > 0.5f) 28 y = y + x - 1; 29 else if (y <= -0.5f) 30 y = y + x + 1; 31 else 32 y = y + x; 33 if (u.i >> 31) 34 y = -y; 35 return y; 36 } 37