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2aa62f2b | 1 | /* @(#)s_modf.c 5.1 93/09/24 */\r |
2 | /*\r | |
3 | * ====================================================\r | |
4 | * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.\r | |
5 | *\r | |
6 | * Developed at SunPro, a Sun Microsystems, Inc. business.\r | |
7 | * Permission to use, copy, modify, and distribute this\r | |
8 | * software is freely granted, provided that this notice\r | |
9 | * is preserved.\r | |
10 | * ====================================================\r | |
11 | */\r | |
12 | #include <LibConfig.h>\r | |
13 | #include <sys/EfiCdefs.h>\r | |
14 | #if defined(LIBM_SCCS) && !defined(lint)\r | |
15 | __RCSID("$NetBSD: s_modf.c,v 1.11 2002/05/26 22:01:57 wiz Exp $");\r | |
16 | #endif\r | |
17 | \r | |
18 | /*\r | |
19 | * modf(double x, double *iptr)\r | |
20 | * return fraction part of x, and return x's integral part in *iptr.\r | |
21 | * Method:\r | |
22 | * Bit twiddling.\r | |
23 | *\r | |
24 | * Exception:\r | |
25 | * No exception.\r | |
26 | */\r | |
27 | \r | |
28 | #include "math.h"\r | |
29 | #include "math_private.h"\r | |
30 | \r | |
31 | static const double one = 1.0;\r | |
32 | \r | |
33 | double\r | |
34 | modf(double x, double *iptr)\r | |
35 | {\r | |
36 | int32_t i0,i1,j0;\r | |
37 | u_int32_t i;\r | |
38 | EXTRACT_WORDS(i0,i1,x);\r | |
39 | j0 = ((i0>>20)&0x7ff)-0x3ff; /* exponent of x */\r | |
40 | if(j0<20) { /* integer part in high x */\r | |
41 | if(j0<0) { /* |x|<1 */\r | |
42 | INSERT_WORDS(*iptr,i0&0x80000000,0); /* *iptr = +-0 */\r | |
43 | return x;\r | |
44 | } else {\r | |
45 | i = (0x000fffff)>>j0;\r | |
46 | if(((i0&i)|i1)==0) { /* x is integral */\r | |
47 | u_int32_t high;\r | |
48 | *iptr = x;\r | |
49 | GET_HIGH_WORD(high,x);\r | |
50 | INSERT_WORDS(x,high&0x80000000,0); /* return +-0 */\r | |
51 | return x;\r | |
52 | } else {\r | |
53 | INSERT_WORDS(*iptr,i0&(~i),0);\r | |
54 | return x - *iptr;\r | |
55 | }\r | |
56 | }\r | |
57 | } else if (j0>51) { /* no fraction part */\r | |
58 | u_int32_t high;\r | |
59 | *iptr = x*one;\r | |
60 | GET_HIGH_WORD(high,x);\r | |
61 | INSERT_WORDS(x,high&0x80000000,0); /* return +-0 */\r | |
62 | return x;\r | |
63 | } else { /* fraction part in low x */\r | |
64 | i = ((u_int32_t)(0xffffffff))>>(j0-20);\r | |
65 | if((i1&i)==0) { /* x is integral */\r | |
66 | u_int32_t high;\r | |
67 | *iptr = x;\r | |
68 | GET_HIGH_WORD(high,x);\r | |
69 | INSERT_WORDS(x,high&0x80000000,0); /* return +-0 */\r | |
70 | return x;\r | |
71 | } else {\r | |
72 | INSERT_WORDS(*iptr,i0,i1&(~i));\r | |
73 | return x - *iptr;\r | |
74 | }\r | |
75 | }\r | |
76 | }\r |