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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 |
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