1 /* 2 * Copyright (C) 1995 Advanced RISC Machines Limited. All rights reserved. 3 * 4 * This software may be freely used, copied, modified, and distributed 5 * provided that the above copyright notice is preserved in all copies of the 6 * software. 7 */ 8 9 /* -*-C-*- 10 * 11 * $Revision: 1.3 $ 12 * $Date: 2004/12/27 14:00:53 $ 13 * 14 * 15 * angel_endian.h - target endianness independent read/write primitives. 16 */ 17 18 #ifndef angel_endian_h 19 #define angel_endian_h 20 21 /* 22 * The endianness of the data being processed needs to be known, but 23 * the host endianness is not required (since the data is constructed 24 * using bytes). At the moment these are provided as macros. This 25 * gives the compiler freedom in optimising individual calls. However, 26 * if space is at a premium then functions should be provided. 27 * 28 * NOTE: These macros assume that the data has been packed in the same format 29 * as the packing on the build host. If this is not the case then 30 * the wrong addresses could be used when dealing with structures. 31 * 32 */ 33 34 /* 35 * For all the following routines the target endianness is defined by the 36 * following boolean definitions. 37 */ 38 #define BE (1 == 1) /* TRUE : big-endian */ 39 #define LE (1 == 0) /* FALSE : little-endian */ 40 41 /* 42 * The following type definitions are used by the endianness converting 43 * macros. 44 */ 45 typedef unsigned char U8; 46 typedef U8 *P_U8; 47 typedef const U8 *CP_U8; 48 49 typedef unsigned short U16; 50 typedef U16 *P_U16; 51 52 typedef unsigned int U32; 53 typedef U32 *P_U32; 54 55 /* 56 * If the endianness of the host and target are known (fixed) and the same 57 * then the following macro definitions can be used. These just directly copy 58 * the data. 59 * 60 * #define READ(e,a) (a) 61 * #define WRITE(e,a,v) ((a) = (v)) 62 * #define PREAD(e,a) (a) 63 * #define PWRITE(e,a,v) (*(a) = (v)) 64 */ 65 66 /* 67 * These macros assume that a byte (char) is 8bits in size, and that the 68 * endianness is not important when reading or writing bytes. 69 */ 70 #define PUT8(a,v) (*((P_U8)(a)) = (U8)(v)) 71 #define PUT16LE(a,v) (PUT8(a,((v) & 0xFF)), \ 72 PUT8((((P_U8)(a)) + sizeof(char)),((v) >> 8))) 73 #define PUT16BE(a,v) (PUT8(a,((v) >> 8)), \ 74 PUT8((((P_U8)(a)) + sizeof(char)),((v) & 0xFF))) 75 #define PUT32LE(a,v) (PUT16LE(a,v), \ 76 PUT16LE((((P_U8)(a)) + sizeof(short)),((v) >> 16))) 77 #define PUT32BE(a,v) (PUT16BE(a,((v) >> 16)), \ 78 PUT16BE((((P_U8)(a)) + sizeof(short)),v)) 79 80 #define GET8(a) (*((CP_U8)(a))) 81 #define GET16LE(a) (GET8(a) | (((U16)GET8(((CP_U8)(a)) + sizeof(char))) << 8)) 82 #define GET16BE(a) ((((U16)GET8(a)) << 8) | GET8(((CP_U8)(a)) + sizeof(char))) 83 #define GET32LE(a) (GET16LE(a) | \ 84 (((U32)GET16LE(((CP_U8)(a)) + sizeof(short))) << 16)) 85 #define GET32BE(a) ((((U32)GET16BE(a)) << 16) | \ 86 GET16BE(((CP_U8)(a)) + sizeof(short))) 87 88 /* 89 * These macros simplify the code in respect to reading and writing the 90 * correct size data when dealing with endianness. "e" is TRUE if we are 91 * dealing with big-endian data, FALSE if we are dealing with little-endian. 92 */ 93 94 /* void WRITE(int endianness, void *address, unsigned value); */ 95 96 #define WRITE16(e,a,v) ((e) ? PUT16BE(&(a),v) : PUT16LE(&(a),v)) 97 #define WRITE32(e,a,v) ((e) ? PUT32BE(&(a),v) : PUT32LE(&(a),v)) 98 #define WRITE(e,a,v) ((sizeof(v) == sizeof(char)) ? \ 99 PUT8(&(a),v) : ((sizeof(v) == sizeof(short)) ? \ 100 WRITE16(e,a,v) : WRITE32(e,a,v))) 101 102 /* unsigned READ(int endianness, void *address) */ 103 #define READ16(e,a) ((e) ? GET16BE(&(a)) : GET16LE(&(a))) 104 #define READ32(e,a) ((e) ? GET32BE(&(a)) : GET32LE(&(a))) 105 #define READ(e,a) ((sizeof(a) == sizeof(char)) ? \ 106 GET8((CP_U8)&(a)) : ((sizeof(a) == sizeof(short)) ? \ 107 READ16(e,a) : READ32(e,a))) 108 109 /* void PWRITE(int endianness, void *address, unsigned value); */ 110 #define PWRITE16(e,a,v) ((e) ? PUT16BE(a,v) : PUT16LE(a,v)) 111 #define PWRITE32(e,a,v) ((e) ? PUT32BE(a,v) : PUT32LE(a,v)) 112 #define PWRITE(e,a,v) ((sizeof(v) == sizeof(char)) ? \ 113 PUT8(a,v) : ((sizeof(v) == sizeof(short)) ? \ 114 PWRITE16(e,a,v) : PWRITE32(e,a,v))) 115 116 /* unsigned PREAD(int endianness, void *address) */ 117 #define PREAD16(e,a) ((e) ? GET16BE(a) : GET16LE(a)) 118 #define PREAD32(e,a) ((e) ? GET32BE(a) : GET32LE(a)) 119 #define PREAD(e,a) ((sizeof(*(a)) == sizeof(char)) ? \ 120 GET8((CP_U8)a) : ((sizeof(*(a)) == sizeof(short)) ? \ 121 PREAD16(e,a) : PREAD32(e,a))) 122 123 #endif /* !defined(angel_endian_h) */ 124 125 /* EOF angel_endian.h */ 126