micropython/lib/libm/roundf.c

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/*****************************************************************************/
/*****************************************************************************/
// roundf from musl-0.9.15
/*****************************************************************************/
/*****************************************************************************/
#include "libm.h"
float roundf(float x)
{
union {float f; uint32_t i;} u = {x};
int e = u.i >> 23 & 0xff;
float_t y;
if (e >= 0x7f+23)
return x;
if (u.i >> 31)
x = -x;
if (e < 0x7f-1) {
FORCE_EVAL(x + 0x1p23f);
return 0*u.f;
}
y = (float)(x + 0x1p23f) - 0x1p23f - x;
if (y > 0.5f)
y = y + x - 1;
else if (y <= -0.5f)
y = y + x + 1;
else
y = y + x;
if (u.i >> 31)
y = -y;
return y;
}