/*
|
* ====================================================
|
* 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.
|
* ====================================================
|
*/
|
|
/*
|
* floor(x)
|
* Return x rounded toward -inf to integral value
|
* Method:
|
* Bit twiddling.
|
* Exception:
|
* Inexact flag raised if x not equal to floor(x).
|
*/
|
|
/*#include <features.h>*/
|
/* Prevent math.h from defining a colliding inline */
|
#undef __USE_EXTERN_INLINES
|
#include "math_libm.h"
|
#include "math_private.h"
|
|
static const double huge = 1.0e300;
|
|
double floor(double x)
|
{
|
int32_t i0,i1,j0;
|
u_int32_t i,j;
|
EXTRACT_WORDS(i0,i1,x);
|
j0 = ((i0>>20)&0x7ff)-0x3ff;
|
if(j0<20) {
|
if(j0<0) { /* raise inexact if x != 0 */
|
if(huge+x>0.0) {/* return 0*sign(x) if |x|<1 */
|
if(i0>=0) {i0=i1=0;}
|
else if(((i0&0x7fffffff)|i1)!=0)
|
{ i0=0xbff00000;i1=0;}
|
}
|
} else {
|
i = (0x000fffff)>>j0;
|
if(((i0&i)|i1)==0) return x; /* x is integral */
|
if(huge+x>0.0) { /* raise inexact flag */
|
if(i0<0) i0 += (0x00100000)>>j0;
|
i0 &= (~i); i1=0;
|
}
|
}
|
} else if (j0>51) {
|
if(j0==0x400) return x+x; /* inf or NaN */
|
else return x; /* x is integral */
|
} else {
|
i = ((u_int32_t)(0xffffffff))>>(j0-20);
|
if((i1&i)==0) return x; /* x is integral */
|
if(huge+x>0.0) { /* raise inexact flag */
|
if(i0<0) {
|
if(j0==20) i0+=1;
|
else {
|
j = i1+(1<<(52-j0));
|
if(j<(u_int32_t)i1) i0 +=1 ; /* got a carry */
|
i1=j;
|
}
|
}
|
i1 &= (~i);
|
}
|
}
|
INSERT_WORDS(x,i0,i1);
|
return x;
|
}
|
libm_hidden_def(floor)
|
