| | 1 | /* |
| | 2 | * Copyright (c) 1999 Apple Computer, Inc. All rights reserved. |
| | 3 | * |
| | 4 | * @APPLE_LICENSE_HEADER_START@ |
| | 5 | * |
| | 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 |
| | 15 | * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES, |
| | 16 | * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY, |
| | 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. |
| | 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 | } |
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