1 | /* s_modfl.c -- long double version of s_modf.c. |
2 | */ |
3 | |
4 | /* |
5 | * ==================================================== |
6 | * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved. |
7 | * |
8 | * Developed at SunPro, a Sun Microsystems, Inc. business. |
9 | * Permission to use, copy, modify, and distribute this |
10 | * software is freely granted, provided that this notice |
11 | * is preserved. |
12 | * ==================================================== |
13 | */ |
14 | |
15 | /* |
16 | * modfl(long double x, long double *iptr) |
17 | * return fraction part of x, and return x's integral part in *iptr. |
18 | * Method: |
19 | * Bit twiddling. |
20 | * |
21 | * Exception: |
22 | * No exception. |
23 | */ |
24 | |
25 | #include <math.h> |
26 | #include <math_private.h> |
27 | #include <libm-alias-ldouble.h> |
28 | |
29 | static const long double one = 1.0; |
30 | |
31 | long double |
32 | __modfl(long double x, long double *iptr) |
33 | { |
34 | int32_t i0,i1,j0; |
35 | uint32_t i,se; |
36 | GET_LDOUBLE_WORDS(se,i0,i1,x); |
37 | j0 = (se&0x7fff)-0x3fff; /* exponent of x */ |
38 | if(j0<32) { /* integer part in high x */ |
39 | if(j0<0) { /* |x|<1 */ |
40 | SET_LDOUBLE_WORDS(*iptr,se&0x8000,0,0); /* *iptr = +-0 */ |
41 | return x; |
42 | } else { |
43 | i = (0x7fffffff)>>j0; |
44 | if(((i0&i)|i1)==0) { /* x is integral */ |
45 | *iptr = x; |
46 | SET_LDOUBLE_WORDS(x,se&0x8000,0,0); /* return +-0 */ |
47 | return x; |
48 | } else { |
49 | SET_LDOUBLE_WORDS(*iptr,se,i0&(~i),0); |
50 | return x - *iptr; |
51 | } |
52 | } |
53 | } else if (__builtin_expect(j0>63, 0)) { /* no fraction part */ |
54 | *iptr = x*one; |
55 | /* We must handle NaNs separately. */ |
56 | if (j0 == 0x4000 && ((i0 & 0x7fffffff) | i1)) |
57 | return x*one; |
58 | SET_LDOUBLE_WORDS(x,se&0x8000,0,0); /* return +-0 */ |
59 | return x; |
60 | } else { /* fraction part in low x */ |
61 | i = ((uint32_t)(0x7fffffff))>>(j0-32); |
62 | if((i1&i)==0) { /* x is integral */ |
63 | *iptr = x; |
64 | SET_LDOUBLE_WORDS(x,se&0x8000,0,0); /* return +-0 */ |
65 | return x; |
66 | } else { |
67 | SET_LDOUBLE_WORDS(*iptr,se,i0,i1&(~i)); |
68 | return x - *iptr; |
69 | } |
70 | } |
71 | } |
72 | libm_alias_ldouble (__modf, modf) |
73 | |