1 | /* s_modfl.c -- long double version of s_modf.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 | /* |
18 | * modfl(long double x, long double *iptr) |
19 | * return fraction part of x, and return x's integral part in *iptr. |
20 | * Method: |
21 | * Bit twiddling. |
22 | * |
23 | * Exception: |
24 | * No exception. |
25 | */ |
26 | |
27 | #include <math.h> |
28 | #include <math_private.h> |
29 | #include <libm-alias-ldouble.h> |
30 | |
31 | static const long double one = 1.0; |
32 | |
33 | long double |
34 | __modfl(long double x, long double *iptr) |
35 | { |
36 | int32_t i0,i1,j0; |
37 | uint32_t i,se; |
38 | GET_LDOUBLE_WORDS(se,i0,i1,x); |
39 | j0 = (se&0x7fff)-0x3fff; /* exponent of x */ |
40 | if(j0<32) { /* integer part in high x */ |
41 | if(j0<0) { /* |x|<1 */ |
42 | SET_LDOUBLE_WORDS(*iptr,se&0x8000,0,0); /* *iptr = +-0 */ |
43 | return x; |
44 | } else { |
45 | i = (0x7fffffff)>>j0; |
46 | if(((i0&i)|i1)==0) { /* x is integral */ |
47 | *iptr = x; |
48 | SET_LDOUBLE_WORDS(x,se&0x8000,0,0); /* return +-0 */ |
49 | return x; |
50 | } else { |
51 | SET_LDOUBLE_WORDS(*iptr,se,i0&(~i),0); |
52 | return x - *iptr; |
53 | } |
54 | } |
55 | } else if (__builtin_expect(j0>63, 0)) { /* no fraction part */ |
56 | *iptr = x*one; |
57 | /* We must handle NaNs separately. */ |
58 | if (j0 == 0x4000 && ((i0 & 0x7fffffff) | i1)) |
59 | return x*one; |
60 | SET_LDOUBLE_WORDS(x,se&0x8000,0,0); /* return +-0 */ |
61 | return x; |
62 | } else { /* fraction part in low x */ |
63 | i = ((uint32_t)(0x7fffffff))>>(j0-32); |
64 | if((i1&i)==0) { /* x is integral */ |
65 | *iptr = x; |
66 | SET_LDOUBLE_WORDS(x,se&0x8000,0,0); /* return +-0 */ |
67 | return x; |
68 | } else { |
69 | SET_LDOUBLE_WORDS(*iptr,se,i0,i1&(~i)); |
70 | return x - *iptr; |
71 | } |
72 | } |
73 | } |
74 | libm_alias_ldouble (__modf, modf) |
75 | |