mirror of
https://github.com/KolibriOS/kolibrios.git
synced 2024-12-16 03:42:35 +03:00
135 lines
2.7 KiB
C
135 lines
2.7 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.
|
|
* ====================================================
|
|
*/
|
|
|
|
/*
|
|
FUNCTION
|
|
<<floor>>, <<floorf>>, <<ceil>>, <<ceilf>>---floor and ceiling
|
|
INDEX
|
|
floor
|
|
INDEX
|
|
floorf
|
|
INDEX
|
|
ceil
|
|
INDEX
|
|
ceilf
|
|
|
|
ANSI_SYNOPSIS
|
|
#include <math.h>
|
|
double floor(double <[x]>);
|
|
float floorf(float <[x]>);
|
|
double ceil(double <[x]>);
|
|
float ceilf(float <[x]>);
|
|
|
|
TRAD_SYNOPSIS
|
|
#include <math.h>
|
|
double floor(<[x]>)
|
|
double <[x]>;
|
|
float floorf(<[x]>)
|
|
float <[x]>;
|
|
double ceil(<[x]>)
|
|
double <[x]>;
|
|
float ceilf(<[x]>)
|
|
float <[x]>;
|
|
|
|
DESCRIPTION
|
|
<<floor>> and <<floorf>> find
|
|
@tex
|
|
$\lfloor x \rfloor$,
|
|
@end tex
|
|
the nearest integer less than or equal to <[x]>.
|
|
<<ceil>> and <<ceilf>> find
|
|
@tex
|
|
$\lceil x\rceil$,
|
|
@end tex
|
|
the nearest integer greater than or equal to <[x]>.
|
|
|
|
RETURNS
|
|
<<floor>> and <<ceil>> return the integer result as a double.
|
|
<<floorf>> and <<ceilf>> return the integer result as a float.
|
|
|
|
PORTABILITY
|
|
<<floor>> and <<ceil>> are ANSI.
|
|
<<floorf>> and <<ceilf>> are extensions.
|
|
|
|
|
|
*/
|
|
|
|
/*
|
|
* 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 "fdlibm.h"
|
|
|
|
#ifndef _DOUBLE_IS_32BITS
|
|
|
|
#ifdef __STDC__
|
|
static const double huge = 1.0e300;
|
|
#else
|
|
static double huge = 1.0e300;
|
|
#endif
|
|
|
|
#ifdef __STDC__
|
|
double floor(double x)
|
|
#else
|
|
double floor(x)
|
|
double x;
|
|
#endif
|
|
{
|
|
__int32_t i0,i1,j0;
|
|
__uint32_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 = ((__uint32_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<i1) i0 +=1 ; /* got a carry */
|
|
i1=j;
|
|
}
|
|
}
|
|
i1 &= (~i);
|
|
}
|
|
}
|
|
INSERT_WORDS(x,i0,i1);
|
|
return x;
|
|
}
|
|
|
|
#endif /* _DOUBLE_IS_32BITS */
|