fb0c37e801bde023b5136b205c2529150a4c7902
[kopensolaris-gnu/glibc.git] / sysdeps / ieee754 / ldbl-96 / s_floorl.c
1 /* s_floorl.c -- long double version of s_floor.c.
2  * Conversion to long double by Ulrich Drepper,
3  * Cygnus Support, drepper@cygnus.com.
4  */
5
6 /*
7  * ====================================================
8  * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
9  *
10  * Developed at SunPro, a Sun Microsystems, Inc. business.
11  * Permission to use, copy, modify, and distribute this
12  * software is freely granted, provided that this notice
13  * is preserved.
14  * ====================================================
15  */
16
17 #if defined(LIBM_SCCS) && !defined(lint)
18 static char rcsid[] = "$NetBSD: $";
19 #endif
20
21 /*
22  * floorl(x)
23  * Return x rounded toward -inf to integral value
24  * Method:
25  *      Bit twiddling.
26  * Exception:
27  *      Inexact flag raised if x not equal to floor(x).
28  */
29
30 #include "math.h"
31 #include "math_private.h"
32
33 #ifdef __STDC__
34 static const long double huge = 1.0e4930;
35 #else
36 static long double huge = 1.0e4930;
37 #endif
38
39 #ifdef __STDC__
40         long double __floorl(long double x)
41 #else
42         long double __floorl(x)
43         long double x;
44 #endif
45 {
46         int32_t i1,j0;
47         u_int32_t i,j,se,i0,sx;
48         GET_LDOUBLE_WORDS(se,i0,i1,x);
49         sx = (se>>15)&1;
50         j0 = (se&0x7fff)-0x3fff;
51         if(j0<31) {
52             if(j0<0) {  /* raise inexact if x != 0 */
53                 if(huge+x>0.0) {/* return 0*sign(x) if |x|<1 */
54                     if(sx==0) {se=0;i0=i1=0;}
55                     else if(((se&0x7fff)|i0|i1)!=0)
56                         { se=0xbfff;i0=i1=0;}
57                 }
58             } else {
59                 i = (0x7fffffff)>>j0;
60                 if(((i0&i)|i1)==0) return x; /* x is integral */
61                 if(huge+x>0.0) {        /* raise inexact flag */
62                     if(sx) {
63                         if (j0>0) i0 += (0x80000000)>>j0;
64                         else ++se;
65                     }
66                     i0 &= (~i); i1=0;
67                 }
68             }
69         } else if (j0>62) {
70             if(j0==0x4000) return x+x;  /* inf or NaN */
71             else return x;              /* x is integral */
72         } else {
73             i = ((u_int32_t)(0xffffffff))>>(j0-31);
74             if((i1&i)==0) return x;     /* x is integral */
75             if(huge+x>0.0) {            /* raise inexact flag */
76                 if(sx) {
77                     if(j0==31) i0+=1;
78                     else {
79                         j = i1+(1<<(63-j0));
80                         if(j<i1) i0 +=1 ;       /* got a carry */
81                         i1=j;
82                     }
83                 }
84                 i1 &= (~i);
85             }
86         }
87         SET_LDOUBLE_WORDS(x,se,i0,i1);
88         return x;
89 }
90 weak_alias (__floorl, floorl)