ceilf.c 434 字节
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#include "libm.h"

float ceilf(float x)
{
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	union {float f; uint32_t i;} u = {x};
	int e = (int)(u.i >> 23 & 0xff) - 0x7f;
	uint32_t m;
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	if (e >= 23)
		return x;
	if (e >= 0) {
		m = 0x007fffff >> e;
		if ((u.i & m) == 0)
			return x;
		FORCE_EVAL(x + 0x1p120f);
		if (u.i >> 31 == 0)
			u.i += m;
		u.i &= ~m;
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	} else {
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		FORCE_EVAL(x + 0x1p120f);
		if (u.i >> 31)
			u.f = -0.0;
		else if (u.i << 1)
			u.f = 1.0;
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	}
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	return u.f;
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}