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/* @(#)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 */

Line No.	Rev	Author	Line
1	39	lampret
2			`/* @(#)s_floor.c 5.1 93/09/24 */`
3			`/*`
4			`* ====================================================`
5			`* Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.`
6			`*`
7			`* Developed at SunPro, a Sun Microsystems, Inc. business.`
8			`* Permission to use, copy, modify, and distribute this`
9			`* software is freely granted, provided that this notice`
10			`* is preserved.`
11			`* ====================================================`
12			`*/`
13
14			`/*`
15			`FUNCTION`
16			`<<floor>>, <<floorf>>, <<ceil>>, <<ceilf>>---floor and ceiling`
17			`INDEX`
18			`floor`
19			`INDEX`
20			`floorf`
21			`INDEX`
22			`ceil`
23			`INDEX`
24			`ceilf`
25
26			`ANSI_SYNOPSIS`
27			`#include <math.h>`
28			`double floor(double <[x]>);`
29			`float floorf(float <[x]>);`
30			`double ceil(double <[x]>);`
31			`float ceilf(float <[x]>);`
32
33			`TRAD_SYNOPSIS`
34			`#include <math.h>`
35			`double floor(<[x]>)`
36			`double <[x]>;`
37			`float floorf(<[x]>)`
38			`float <[x]>;`
39			`double ceil(<[x]>)`
40			`double <[x]>;`
41			`float ceilf(<[x]>)`
42			`float <[x]>;`
43
44			`DESCRIPTION`
45			`<<floor>> and <<floorf>> find`
46			`@tex`
47			`$\lfloor x \rfloor$,`
48			`@end tex`
49			`the nearest integer less than or equal to <[x]>.`
50			`<<ceil>> and <<ceilf>> find`
51			`@tex`
52			`$\lceil x\rceil$,`
53			`@end tex`
54			`the nearest integer greater than or equal to <[x]>.`
55
56			`RETURNS`
57			`<<floor>> and <<ceil>> return the integer result as a double.`
58			`<<floorf>> and <<ceilf>> return the integer result as a float.`
59
60			`PORTABILITY`
61			`<<floor>> and <<ceil>> are ANSI.`
62			`<<floorf>> and <<ceilf>> are extensions.`
63
64
65			`*/`
66
67			`/*`
68			`* floor(x)`
69			`* Return x rounded toward -inf to integral value`
70			`* Method:`
71			`* Bit twiddling.`
72			`* Exception:`
73			`* Inexact flag raised if x not equal to floor(x).`
74			`*/`
75
76			`#include "fdlibm.h"`
77
78			`#ifndef _DOUBLE_IS_32BITS`
79
80			`#ifdef __STDC__`
81			`static const double huge = 1.0e300;`
82			`#else`
83			`static double huge = 1.0e300;`
84			`#endif`
85
86			`#ifdef __STDC__`
87			`double floor(double x)`
88			`#else`
89			`double floor(x)`
90			`double x;`
91			`#endif`
92			`{`
93			`__int32_t i0,i1,j0;`
94			`__uint32_t i,j;`
95			`EXTRACT_WORDS(i0,i1,x);`
96			`j0 = ((i0>>20)&0x7ff)-0x3ff;`
97			`if(j0<20) {`
98			`if(j0<0) { /* raise inexact if x != 0 */`
99			`if(huge+x>0.0) {/* return 0sign(x) if \|x\|<1 /`
100			`if(i0>=0) {i0=i1=0;}`
101			`else if(((i0&0x7fffffff)\|i1)!=0)`
102			`{ i0=0xbff00000;i1=0;}`
103			`}`
104			`} else {`
105			`i = (0x000fffff)>>j0;`
106			`if(((i0&i)\|i1)==0) return x; /* x is integral */`
107			`if(huge+x>0.0) { /* raise inexact flag */`
108			`if(i0<0) i0 += (0x00100000)>>j0;`
109			`i0 &= (~i); i1=0;`
110			`}`
111			`}`
112			`} else if (j0>51) {`
113			`if(j0==0x400) return x+x; /* inf or NaN */`
114			`else return x; /* x is integral */`
115			`} else {`
116			`i = ((__uint32_t)(0xffffffff))>>(j0-20);`
117			`if((i1&i)==0) return x; /* x is integral */`
118			`if(huge+x>0.0) { /* raise inexact flag */`
119			`if(i0<0) {`
120			`if(j0==20) i0+=1;`
121			`else {`
122			`j = i1+(1<<(52-j0));`
123			`if(j<i1) i0 +=1 ; /* got a carry */`
124			`i1=j;`
125			`}`
126			`}`
127			`i1 &= (~i);`
128			`}`
129			`}`
130			`INSERT_WORDS(x,i0,i1);`
131			`return x;`
132			`}`
133
134			`#endif /* _DOUBLE_IS_32BITS */`

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[/] [or1k/] [trunk/] [newlib/] [newlib/] [libm/] [math/] [s_floor.c] - Blame information for rev 1765