ref: b9ff09189979b272200d32668b4e42f292512dcd
dir: /posix/s_floorf.c/
/* s_floorf.c -- float version of s_floor.c.
* Conversion to float by Ian Lance Taylor, Cygnus Support, [email protected].
*/
/*
* ====================================================
* 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.
* ====================================================
*/
/*
* 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;
}