OpenCores
URL https://opencores.org/ocsvn/openrisc_me/openrisc_me/trunk

Subversion Repositories openrisc_me

[/] [openrisc/] [trunk/] [gnu-src/] [newlib-1.18.0/] [newlib/] [libm/] [math/] [e_fmod.c] - Blame information for rev 307

Go to most recent revision | Details | Compare with Previous | View Log

Line No. Rev Author Line
1 207 jeremybenn 
 
2 
/* @(#)e_fmod.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 
 * __ieee754_fmod(x,y)
16 
 * Return x mod y in exact arithmetic
17 
 * Method: shift and subtract
18 
 */
19 
 
20 
#include "fdlibm.h"
21 
 
22 
#ifndef _DOUBLE_IS_32BITS
23 
 
24 
#ifdef __STDC__
25 
static const double one = 1.0, Zero[] = {0.0, -0.0,};
26 
#else
27 
static double one = 1.0, Zero[] = {0.0, -0.0,};
28 
#endif
29 
 
30 
#ifdef __STDC__
31 
        double __ieee754_fmod(double x, double y)
32 
#else
33 
        double __ieee754_fmod(x,y)
34 
        double x,y ;
35 
#endif
36 
{
37 
        __int32_t n,hx,hy,hz,ix,iy,sx,i;
38 
        __uint32_t lx,ly,lz;
39 
 
40 
        EXTRACT_WORDS(hx,lx,x);
41 
        EXTRACT_WORDS(hy,ly,y);
42 
        sx = hx&0x80000000;             /* sign of x */
43 
        hx ^=sx;                /* |x| */
44 
        hy &= 0x7fffffff;       /* |y| */
45 
 
46 
    /* purge off exception values */
47 
        if((hy|ly)==0||(hx>=0x7ff00000)||        /* y=0,or x not finite */
48 
          ((hy|((ly|-ly)>>31))>0x7ff00000))     /* or y is NaN */
49 
            return (x*y)/(x*y);
50 
        if(hx<=hy) {
51 
            if((hx<hy)||(lx<ly)) return x;      /* |x|<|y| return x */
52 
            if(lx==ly)
53 
                return Zero[(__uint32_t)sx>>31];        /* |x|=|y| return x*0*/
54 
        }
55 
 
56 
    /* determine ix = ilogb(x) */
57 
        if(hx<0x00100000) {     /* subnormal x */
58 
            if(hx==0) {
59 
                for (ix = -1043, i=lx; i>0; i<<=1) ix -=1;
60 
            } else {
61 
                for (ix = -1022,i=(hx<<11); i>0; i<<=1) ix -=1;
62 
            }
63 
        } else ix = (hx>>20)-1023;
64 
 
65 
    /* determine iy = ilogb(y) */
66 
        if(hy<0x00100000) {     /* subnormal y */
67 
            if(hy==0) {
68 
                for (iy = -1043, i=ly; i>0; i<<=1) iy -=1;
69 
            } else {
70 
                for (iy = -1022,i=(hy<<11); i>0; i<<=1) iy -=1;
71 
            }
72 
        } else iy = (hy>>20)-1023;
73 
 
74 
    /* set up {hx,lx}, {hy,ly} and align y to x */
75 
        if(ix >= -1022)
76 
            hx = 0x00100000|(0x000fffff&hx);
77 
        else {          /* subnormal x, shift x to normal */
78 
            n = -1022-ix;
79 
            if(n<=31) {
80 
                hx = (hx<<n)|(lx>>(32-n));
81 
                lx <<= n;
82 
            } else {
83 
                hx = lx<<(n-32);
84 
                lx = 0;
85 
            }
86 
        }
87 
        if(iy >= -1022)
88 
            hy = 0x00100000|(0x000fffff&hy);
89 
        else {          /* subnormal y, shift y to normal */
90 
            n = -1022-iy;
91 
            if(n<=31) {
92 
                hy = (hy<<n)|(ly>>(32-n));
93 
                ly <<= n;
94 
            } else {
95 
                hy = ly<<(n-32);
96 
                ly = 0;
97 
            }
98 
        }
99 
 
100 
    /* fix point fmod */
101 
        n = ix - iy;
102 
        while(n--) {
103 
            hz=hx-hy;lz=lx-ly; if(lx<ly) hz -= 1;
104 
            if(hz<0){hx = hx+hx+(lx>>31); lx = lx+lx;}
105 
            else {
106 
                if((hz|lz)==0)           /* return sign(x)*0 */
107 
                    return Zero[(__uint32_t)sx>>31];
108 
                hx = hz+hz+(lz>>31); lx = lz+lz;
109 
            }
110 
        }
111 
        hz=hx-hy;lz=lx-ly; if(lx<ly) hz -= 1;
112 
        if(hz>=0) {hx=hz;lx=lz;}
113 
 
114 
    /* convert back to floating value and restore the sign */
115 
        if((hx|lx)==0)                   /* return sign(x)*0 */
116 
            return Zero[(__uint32_t)sx>>31];
117 
        while(hx<0x00100000) {          /* normalize x */
118 
            hx = hx+hx+(lx>>31); lx = lx+lx;
119 
            iy -= 1;
120 
        }
121 
        if(iy>= -1022) {        /* normalize output */
122 
            hx = ((hx-0x00100000)|((iy+1023)<<20));
123 
            INSERT_WORDS(x,hx|sx,lx);
124 
        } else {                /* subnormal output */
125 
            n = -1022 - iy;
126 
            if(n<=20) {
127 
                lx = (lx>>n)|((__uint32_t)hx<<(32-n));
128 
                hx >>= n;
129 
            } else if (n<=31) {
130 
                lx = (hx<<(32-n))|(lx>>n); hx = sx;
131 
            } else {
132 
                lx = hx>>(n-32); hx = sx;
133 
            }
134 
            INSERT_WORDS(x,hx|sx,lx);
135 
            x *= one;           /* create necessary signal */
136 
        }
137 
        return x;               /* exact output */
138 
}
139 
 
140 
#endif /* defined(_DOUBLE_IS_32BITS) */

powered by: WebSVN 2.1.0

© copyright 1999-2024 OpenCores.org, equivalent to Oliscience, all rights reserved. OpenCores®, registered trademark.