64 lines
1.5 KiB
C
64 lines
1.5 KiB
C
|
/* s_floorf.c -- float version of s_floor.c.
|
||
|
|
* Conversion to float by Ian Lance Taylor, Cygnus Support, ian@cygnus.com.
|
||
|
|
*/
|
||
|
|
|
||
|
|
/*
|
||
|
|
* ====================================================
|
||
|
|
* 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.
|
||
|
|
* ====================================================
|
||
|
|
*/
|
||
|
|
|
||
|
|
#include <sys/cdefs.h>
|
||
|
|
#if defined(LIBM_SCCS) && !defined(lint)
|
||
|
|
__RCSID("$NetBSD: s_floorf.c,v 1.8 2008/04/25 22:21:53 christos Exp $");
|
||
|
|
#endif
|
||
|
|
|
||
|
|
/*
|
||
|
|
* floorf(x)
|
||
|
|
* Return x rounded toward -inf to integral value
|
||
|
|
* Method:
|
||
|
|
* Bit twiddling.
|
||
|
|
* Exception:
|
||
|
|
* Inexact flag raised if x not equal to floorf(x).
|
||
|
|
*/
|
||
|
|
|
||
|
|
#include "math.h"
|
||
|
|
#include "math_private.h"
|
||
|
|
|
||
|
|
static const float huge = 1.0e30;
|
||
|
|
|
||
|
|
float
|
||
|
|
floorf(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>(float)0.0) {/* return 0*sign(x) if |x|<1 */
|
||
|
|
if(i0>=0) {i0=0;}
|
||
|
|
else if((i0&0x7fffffff)!=0)
|
||
|
|
{ i0=0xbf800000;}
|
||
|
|
}
|
||
|
|
} else {
|
||
|
|
i = (0x007fffff)>>jj0;
|
||
|
|
if((i0&i)==0) return x; /* x is integral */
|
||
|
|
if(huge+x>(float)0.0) { /* raise inexact flag */
|
||
|
|
if(i0<0) i0 += (0x00800000)>>jj0;
|
||
|
|
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;
|
||
|
|
}
|