1 /* $NetBSD: byte_swap.h,v 1.13 2013/01/28 06:16:05 matt Exp $ */ 2 3 /*- 4 * Copyright (c) 1997, 1999, 2002 The NetBSD Foundation, Inc. 5 * All rights reserved. 6 * 7 * This code is derived from software contributed to The NetBSD Foundation 8 * by Charles M. Hannum, Neil A. Carson, and Jason R. Thorpe. 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 19 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 20 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 21 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 22 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 23 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 24 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 25 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 26 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 27 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 28 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 29 * POSSIBILITY OF SUCH DAMAGE. 30 */ 31 32 #ifndef _ARM_BYTE_SWAP_H_ 33 #define _ARM_BYTE_SWAP_H_ 34 35 #ifdef _LOCORE 36 37 #if defined(_ARM_ARCH_6) || defined(_ARM_ARCH_7) 38 39 #define BSWAP16(_src, _dst, _tmp) \ 40 rev16 _dst, _src 41 #define BSWAP32(_src, _dst, _tmp) \ 42 rev _dst, _src 43 44 #else 45 46 #define BSWAP16(_src, _dst, _tmp) \ 47 mov _tmp, _src, ror #8 ;\ 48 orr _tmp, _tmp, _tmp, lsr #16 ;\ 49 bic _dst, _tmp, _tmp, lsl #16 50 51 #define BSWAP32(_src, _dst, _tmp) \ 52 eor _tmp, _src, _src, ror #16 ;\ 53 bic _tmp, _tmp, #0x00FF0000 ;\ 54 mov _dst, _src, ror #8 ;\ 55 eor _dst, _dst, _tmp, lsr #8 56 57 #endif 58 59 60 #else 61 62 #ifdef __GNUC__ 63 #include <sys/types.h> 64 __BEGIN_DECLS 65 66 #define __BYTE_SWAP_U32_VARIABLE __byte_swap_u32_variable 67 static __inline uint32_t 68 __byte_swap_u32_variable(uint32_t v) 69 { 70 uint32_t t1; 71 72 #ifdef _ARM_ARCH_6 73 if (!__builtin_constant_p(v)) { 74 __asm("rev\t%0, %1" : "=r" (v) : "0" (v)); 75 return v; 76 } 77 #endif 78 79 t1 = v ^ ((v << 16) | (v >> 16)); 80 t1 &= 0xff00ffffU; 81 v = (v >> 8) | (v << 24); 82 v ^= (t1 >> 8); 83 84 return (v); 85 } 86 87 #define __BYTE_SWAP_U16_VARIABLE __byte_swap_u16_variable 88 static __inline uint16_t 89 __byte_swap_u16_variable(uint16_t v) 90 { 91 92 #ifdef _ARM_ARCH_6 93 if (!__builtin_constant_p(v)) { 94 uint32_t v32 = v; 95 __asm("rev16\t%0, %1" : "=r" (v32) : "0" (v32)); 96 return v32; 97 } 98 #elif !defined(__thumb__) && 0 /* gcc produces decent code for this */ 99 if (!__builtin_constant_p(v)) { 100 uint32_t v0 = v; 101 __asm volatile( 102 "mov %0, %1, ror #8\n" 103 "orr %0, %0, %0, lsr #16\n" 104 "bic %0, %0, %0, lsl #16" 105 : "=&r" (v0) 106 : "0" (v0)); 107 return v0; 108 } 109 #endif 110 v &= 0xffff; 111 v = (v >> 8) | (v << 8); 112 113 return (v); 114 } 115 116 __END_DECLS 117 #endif 118 119 #endif /* _LOCORE */ 120 121 #endif /* _ARM_BYTE_SWAP_H_ */ 122