125 lines
4.6 KiB
C
125 lines
4.6 KiB
C
/*
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* Copyright (C) 1995 Advanced RISC Machines Limited. All rights reserved.
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*
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* This software may be freely used, copied, modified, and distributed
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* provided that the above copyright notice is preserved in all copies of the
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* software.
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*/
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/* -*-C-*-
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*
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* $Revision$
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* $Date$
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*
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*
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* angel_endian.h - target endianness independent read/write primitives.
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*/
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#ifndef angel_endian_h
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#define angel_endian_h
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/*
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* The endianness of the data being processed needs to be known, but
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* the host endianness is not required (since the data is constructed
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* using bytes). At the moment these are provided as macros. This
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* gives the compiler freedom in optimising individual calls. However,
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* if space is at a premium then functions should be provided.
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*
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* NOTE: These macros assume that the data has been packed in the same format
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* as the packing on the build host. If this is not the case then
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* the wrong addresses could be used when dealing with structures.
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*
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*/
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/*
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* For all the following routines the target endianness is defined by the
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* following boolean definitions.
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*/
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#define BE (1 == 1) /* TRUE : big-endian */
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#define LE (1 == 0) /* FALSE : little-endian */
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/*
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* The following type definitions are used by the endianness converting
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* macros.
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*/
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typedef unsigned char U8;
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typedef U8 *P_U8;
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typedef const U8 *CP_U8;
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typedef unsigned short U16;
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typedef U16 *P_U16;
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typedef unsigned int U32;
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typedef U32 *P_U32;
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/*
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* If the endianness of the host and target are known (fixed) and the same
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* then the following macro definitions can be used. These just directly copy
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* the data.
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*
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* #define READ(e,a) (a)
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* #define WRITE(e,a,v) ((a) = (v))
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* #define PREAD(e,a) (a)
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* #define PWRITE(e,a,v) (*(a) = (v))
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*/
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/*
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* These macros assume that a byte (char) is 8bits in size, and that the
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* endianness is not important when reading or writing bytes.
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*/
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#define PUT8(a,v) (*((P_U8)(a)) = (U8)(v))
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#define PUT16LE(a,v) (PUT8(a,((v) & 0xFF)), \
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PUT8((((P_U8)(a)) + sizeof(char)),((v) >> 8)))
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#define PUT16BE(a,v) (PUT8(a,((v) >> 8)), \
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PUT8((((P_U8)(a)) + sizeof(char)),((v) & 0xFF)))
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#define PUT32LE(a,v) (PUT16LE(a,v), \
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PUT16LE((((P_U8)(a)) + sizeof(short)),((v) >> 16)))
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#define PUT32BE(a,v) (PUT16BE(a,((v) >> 16)), \
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PUT16BE((((P_U8)(a)) + sizeof(short)),v))
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#define GET8(a) (*((CP_U8)(a)))
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#define GET16LE(a) (GET8(a) | (((U16)GET8(((CP_U8)(a)) + sizeof(char))) << 8))
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#define GET16BE(a) ((((U16)GET8(a)) << 8) | GET8(((CP_U8)(a)) + sizeof(char)))
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#define GET32LE(a) (GET16LE(a) | \
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(((U32)GET16LE(((CP_U8)(a)) + sizeof(short))) << 16))
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#define GET32BE(a) ((((U32)GET16BE(a)) << 16) | \
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GET16BE(((CP_U8)(a)) + sizeof(short)))
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/*
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* These macros simplify the code in respect to reading and writing the
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* correct size data when dealing with endianness. "e" is TRUE if we are
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* dealing with big-endian data, FALSE if we are dealing with little-endian.
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*/
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/* void WRITE(int endianness, void *address, unsigned value); */
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#define WRITE16(e,a,v) ((e) ? PUT16BE(&(a),v) : PUT16LE(&(a),v))
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#define WRITE32(e,a,v) ((e) ? PUT32BE(&(a),v) : PUT32LE(&(a),v))
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#define WRITE(e,a,v) ((sizeof(v) == sizeof(char)) ? \
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PUT8(&(a),v) : ((sizeof(v) == sizeof(short)) ? \
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WRITE16(e,a,v) : WRITE32(e,a,v)))
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/* unsigned READ(int endianness, void *address) */
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#define READ16(e,a) ((e) ? GET16BE(&(a)) : GET16LE(&(a)))
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#define READ32(e,a) ((e) ? GET32BE(&(a)) : GET32LE(&(a)))
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#define READ(e,a) ((sizeof(a) == sizeof(char)) ? \
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GET8((CP_U8)&(a)) : ((sizeof(a) == sizeof(short)) ? \
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READ16(e,a) : READ32(e,a)))
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/* void PWRITE(int endianness, void *address, unsigned value); */
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#define PWRITE16(e,a,v) ((e) ? PUT16BE(a,v) : PUT16LE(a,v))
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#define PWRITE32(e,a,v) ((e) ? PUT32BE(a,v) : PUT32LE(a,v))
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#define PWRITE(e,a,v) ((sizeof(v) == sizeof(char)) ? \
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PUT8(a,v) : ((sizeof(v) == sizeof(short)) ? \
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PWRITE16(e,a,v) : PWRITE32(e,a,v)))
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/* unsigned PREAD(int endianness, void *address) */
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#define PREAD16(e,a) ((e) ? GET16BE(a) : GET16LE(a))
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#define PREAD32(e,a) ((e) ? GET32BE(a) : GET32LE(a))
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#define PREAD(e,a) ((sizeof(*(a)) == sizeof(char)) ? \
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GET8((CP_U8)a) : ((sizeof(*(a)) == sizeof(short)) ? \
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PREAD16(e,a) : PREAD32(e,a)))
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#endif /* !defined(angel_endian_h) */
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/* EOF angel_endian.h */
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