93 lines
1.7 KiB
C
93 lines
1.7 KiB
C
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/* @(#)z_floor.c 1.0 98/08/13 */
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/*
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FUNCTION
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<<floor>>, <<floorf>>, <<ceil>>, <<ceilf>>---floor and ceiling
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INDEX
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floor
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INDEX
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floorf
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INDEX
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ceil
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INDEX
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ceilf
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ANSI_SYNOPSIS
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#include <math.h>
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double floor(double <[x]>);
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float floorf(float <[x]>);
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double ceil(double <[x]>);
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float ceilf(float <[x]>);
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TRAD_SYNOPSIS
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#include <math.h>
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double floor(<[x]>)
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double <[x]>;
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float floorf(<[x]>)
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float <[x]>;
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double ceil(<[x]>)
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double <[x]>;
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float ceilf(<[x]>)
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float <[x]>;
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DESCRIPTION
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<<floor>> and <<floorf>> find
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@tex
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$\lfloor x \rfloor$,
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@end tex
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the nearest integer less than or equal to <[x]>.
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<<ceil>> and <<ceilf>> find
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@tex
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$\lceil x\rceil$,
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@end tex
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the nearest integer greater than or equal to <[x]>.
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RETURNS
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<<floor>> and <<ceil>> return the integer result as a double.
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<<floorf>> and <<ceilf>> return the integer result as a float.
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PORTABILITY
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<<floor>> and <<ceil>> are ANSI.
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<<floorf>> and <<ceilf>> are extensions.
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*/
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/*****************************************************************
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* floor
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*
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* Input:
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* x - floating point value
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*
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* Output:
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* Smallest integer less than x.
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*
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* Description:
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* This routine returns the smallest integer less than x.
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*
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*****************************************************************/
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#include "fdlibm.h"
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#include "zmath.h"
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#ifndef _DOUBLE_IS_32BITS
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double
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_DEFUN (floor, (double),
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double x)
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{
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double f, y;
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if (x > -1.0 && x < 1.0)
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return (x >= 0 ? 0 : -1.0);
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y = modf (x, &f);
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if (y == 0.0)
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return (x);
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return (x >= 0 ? f : f - 1.0);
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}
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#endif /* _DOUBLE_IS_32BITS */
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