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_OSByteOrder.h (2801B) - Raw

      1 /*
      2  * Copyright (c) 2023 Apple Inc. All rights reserved.
      3  *
      4  * @APPLE_OSREFERENCE_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. The rights granted to you under the License
     10  * may not be used to create, or enable the creation or redistribution of,
     11  * unlawful or unlicensed copies of an Apple operating system, or to
     12  * circumvent, violate, or enable the circumvention or violation of, any
     13  * terms of an Apple operating system software license agreement.
     14  *
     15  * Please obtain a copy of the License at
     16  * http://www.opensource.apple.com/apsl/ and read it before using this file.
     17  *
     18  * The Original Code and all software distributed under the License are
     19  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
     20  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
     21  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
     22  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
     23  * Please see the License for the specific language governing rights and
     24  * limitations under the License.
     25  *
     26  * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
     27  */
     28 
     29 #ifndef _OS__OSBYTEORDERARM_H
     30 #define _OS__OSBYTEORDERARM_H
     31 
     32 #if defined (__arm__) || defined(__arm64__)
     33 
     34 #include <sys/_types.h>
     35 
     36 #if !defined(__DARWIN_OS_INLINE)
     37 # if defined(__STDC_VERSION__) && __STDC_VERSION__ >= 199901L
     38 #        define __DARWIN_OS_INLINE static inline
     39 # elif defined(__MWERKS__) || defined(__cplusplus)
     40 #        define __DARWIN_OS_INLINE static inline
     41 # else
     42 #        define __DARWIN_OS_INLINE static __inline__
     43 # endif
     44 #endif
     45 
     46 /* Generic byte swapping functions. */
     47 
     48 __DARWIN_OS_INLINE
     49 __uint16_t
     50 _OSSwapInt16(
     51 	__uint16_t        _data
     52 	)
     53 {
     54 	/* Reduces to 'rev16' with clang */
     55 	return (__uint16_t)(_data << 8 | _data >> 8);
     56 }
     57 
     58 __DARWIN_OS_INLINE
     59 __uint32_t
     60 _OSSwapInt32(
     61 	__uint32_t        _data
     62 	)
     63 {
     64 #if defined(__llvm__)
     65 	_data = __builtin_bswap32(_data);
     66 #else
     67 	/* This actually generates the best code */
     68 	_data = (((_data ^ (_data >> 16 | (_data << 16))) & 0xFF00FFFF) >> 8) ^ (_data >> 8 | _data << 24);
     69 #endif
     70 
     71 	return _data;
     72 }
     73 
     74 __DARWIN_OS_INLINE
     75 __uint64_t
     76 _OSSwapInt64(
     77 	__uint64_t        _data
     78 	)
     79 {
     80 #if defined(__llvm__)
     81 	return __builtin_bswap64(_data);
     82 #else
     83 	union {
     84 		__uint64_t _ull;
     85 		__uint32_t _ul[2];
     86 	} _u;
     87 
     88 	/* This actually generates the best code */
     89 	_u._ul[0] = (__uint32_t)(_data >> 32);
     90 	_u._ul[1] = (__uint32_t)(_data & 0xffffffff);
     91 	_u._ul[0] = _OSSwapInt32(_u._ul[0]);
     92 	_u._ul[1] = _OSSwapInt32(_u._ul[1]);
     93 	return _u._ull;
     94 #endif
     95 }
     96 
     97 #endif /* defined (__arm__) || defined(__arm64__) */
     98 
     99 #endif /* ! _OS__OSBYTEORDERARM_H */