projects / apple / libc.git / blame
| Commit | Line | Data |
|---|---|---|
| e9ce8d39 A |
1 | /* |
| 2 | * Copyright (c) 1999 Apple Computer, Inc. All rights reserved. | |
| 3 | * | |
| 4 | * @APPLE_LICENSE_HEADER_START@ | |
| 5 | * | |
| 734aad71 A |
6 | * This file contains Original Code and/or Modifications of Original Code |
| 7 | * as defined in and that are subject to the Apple Public Source License | |
| 8 | * Version 2.0 (the 'License'). You may not use this file except in | |
| 9 | * compliance with the License. Please obtain a copy of the License at | |
| 10 | * http://www.opensource.apple.com/apsl/ and read it before using this | |
| 11 | * file. | |
| 12 | * | |
| 13 | * The Original Code and all software distributed under the License are | |
| 14 | * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER | |
| e9ce8d39 A |
15 | * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES, |
| 16 | * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY, | |
| 734aad71 A |
17 | * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT. |
| 18 | * Please see the License for the specific language governing rights and | |
| 19 | * limitations under the License. | |
| e9ce8d39 A |
20 | * |
| 21 | * @APPLE_LICENSE_HEADER_END@ | |
| 22 | */ | |
| 23 | /* @(#)s_isnan.c 5.1 93/09/24 */ | |
| 24 | /* | |
| 25 | * ==================================================== | |
| 26 | * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved. | |
| 27 | * | |
| 28 | * Developed at SunPro, a Sun Microsystems, Inc. business. | |
| 29 | * Permission to use, copy, modify, and distribute this | |
| 30 | * software is freely granted, provided that this notice | |
| 31 | * is preserved. | |
| 32 | * ==================================================== | |
| 33 | */ | |
| 34 | ||
| 35 | #if defined(LIBM_SCCS) && !defined(lint) | |
| 36 | static char rcsid[] = "$NetBSD: s_isnan.c,v 1.8 1995/05/10 20:47:36 jtc Exp $"; | |
| 37 | #endif | |
| 38 | ||
| 39 | /* | |
| 40 | * isnan(x) returns 1 is x is nan, else 0; | |
| 41 | * no branching! | |
| 42 | */ | |
| 43 | ||
| 44 | #include <sys/types.h> | |
| 45 | ||
| 46 | typedef union | |
| 47 | { | |
| 48 | double value; | |
| 49 | struct | |
| 50 | { | |
| 51 | #if defined(__BIG_ENDIAN__) | |
| 52 | u_int32_t msw; | |
| 53 | u_int32_t lsw; | |
| 54 | #else | |
| 55 | u_int32_t lsw; | |
| 56 | u_int32_t msw; | |
| 57 | #endif | |
| 58 | } parts; | |
| 59 | } ieee_double_shape_type; | |
| 60 | /* Get two 32 bit ints from a double. */ | |
| 61 | ||
| 62 | #define EXTRACT_WORDS(ix0,ix1,d) \ | |
| 63 | do { \ | |
| 64 | ieee_double_shape_type ew_u; \ | |
| 65 | ew_u.value = (d); \ | |
| 66 | (ix0) = ew_u.parts.msw; \ | |
| 67 | (ix1) = ew_u.parts.lsw; \ | |
| 68 | } while (0) | |
| 69 | ||
| 70 | ||
| 71 | #ifdef __STDC__ | |
| 72 | int isnan(double x) | |
| 73 | #else | |
| 74 | int isnan(x) | |
| 75 | double x; | |
| 76 | #endif | |
| 77 | { | |
| 78 | int32_t hx,lx; | |
| 79 | EXTRACT_WORDS(hx,lx,x); | |
| 80 | hx &= 0x7fffffff; | |
| 81 | hx |= (u_int32_t)(lx|(-lx))>>31; | |
| 82 | hx = 0x7ff00000 - hx; | |
| 83 | return (int)((u_int32_t)(hx))>>31; | |
| 84 | } |