s_truncf.c
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/* @(#)s_floor.c 5.1 93/09/24 */
/*
* ====================================================
* Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
*
* Developed at SunPro, a Sun Microsystems, Inc. business.
* Permission to use, copy, modify, and distribute this
* software is freely granted, provided that this notice
* is preserved.
* ====================================================
*/
#if 0
#include <sys/cdefs.h>
__FBSDID("$FreeBSD: src/lib/msun/src/s_truncf.c,v 1.1 2004/06/20 09:25:43 das Exp $");
#endif
/*
* truncf(x)
* Return x rounded toward 0 to integral value
* Method:
* Bit twiddling.
* Exception:
* Inexact flag raised if x not equal to truncf(x).
*/
#include "math.h"
#include "math_private.h"
static const float huge = 1.0e30F;
float
truncf(float x)
{
int32_t i0,jj0;
u_int32_t i;
GET_FLOAT_WORD(i0,x);
jj0 = ((i0>>23)&0xff)-0x7f;
if(jj0<23) {
if(jj0<0) { /* raise inexact if x != 0 */
if(huge+x>0.0F) /* |x|<1, so return 0*sign(x) */
i0 &= 0x80000000;
} else {
i = (0x007fffff)>>jj0;
if((i0&i)==0) return x; /* x is integral */
if(huge+x>0.0F) /* raise inexact flag */
i0 &= (~i);
}
} else {
if(jj0==0x80) return x+x; /* inf or NaN */
else return x; /* x is integral */
}
SET_FLOAT_WORD(x,i0);
return x;
}