newlib-cygwin/newlib/libm/mathfp/s_floor.c

93 lines
1.7 KiB
C

/* @(#)z_floor.c 1.0 98/08/13 */
/*
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
*
* Input:
* x - floating point value
*
* Output:
* Smallest integer less than x.
*
* Description:
* This routine returns the smallest integer less than x.
*
*****************************************************************/
#include "fdlibm.h"
#include "zmath.h"
#ifndef _DOUBLE_IS_32BITS
double
_DEFUN (floor, (double),
double x)
{
double f, y;
if (x > -1.0 && x < 1.0)
return (x >= 0 ? 0 : -1.0);
y = modf (x, &f);
if (y == 0.0)
return (x);
return (x >= 0 ? f : f - 1.0);
}
#endif /* _DOUBLE_IS_32BITS */