72 lines
1.6 KiB
C
72 lines
1.6 KiB
C
/* @(#)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.
|
|
* ====================================================
|
|
*/
|
|
|
|
/*
|
|
* floorl(x)
|
|
* Return x rounded toward -inf to integral value
|
|
* Method:
|
|
* Bit twiddling.
|
|
* Exception:
|
|
* Inexact flag raised if x not equal to floor(x).
|
|
*/
|
|
|
|
#include <openlibm_math.h>
|
|
|
|
#include "math_private.h"
|
|
|
|
static const long double huge = 1.0e4930L;
|
|
|
|
long double
|
|
floorl(long double x)
|
|
{
|
|
int64_t i0,i1,jj0;
|
|
u_int64_t i,j;
|
|
GET_LDOUBLE_WORDS64(i0,i1,x);
|
|
jj0 = ((i0>>48)&0x7fff)-0x3fff;
|
|
if(jj0<48) {
|
|
if(jj0<0) { /* raise inexact if x != 0 */
|
|
if(huge+x>0.0) {
|
|
if(i0>=0)
|
|
return 0.0L;
|
|
else if(((i0&0x7fffffffffffffffLL)|i1)!=0)
|
|
return -1.0L;
|
|
}
|
|
} else {
|
|
i = (0x0000ffffffffffffULL)>>jj0;
|
|
if(((i0&i)|i1)==0) return x; /* x is integral */
|
|
if(huge+x>0.0) { /* raise inexact flag */
|
|
if(i0<0) i0 += (0x0001000000000000LL)>>jj0;
|
|
i0 &= (~i); i1=0;
|
|
}
|
|
}
|
|
} else if (jj0>111) {
|
|
if(jj0==0x4000) return x+x; /* inf or NaN */
|
|
else return x; /* x is integral */
|
|
} else {
|
|
i = -1ULL>>(jj0-48);
|
|
if((i1&i)==0) return x; /* x is integral */
|
|
if(huge+x>0.0) { /* raise inexact flag */
|
|
if(i0<0) {
|
|
if(jj0==48) i0+=1;
|
|
else {
|
|
j = i1+(1LL<<(112-jj0));
|
|
if(j<i1) i0 +=1 ; /* got a carry */
|
|
i1=j;
|
|
}
|
|
}
|
|
i1 &= (~i);
|
|
}
|
|
}
|
|
SET_LDOUBLE_WORDS64(x,i0,i1);
|
|
return x;
|
|
}
|