151 lines
4.7 KiB
C
151 lines
4.7 KiB
C
/* Copyright (C) 2009 Wildfire Games.
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* This file is part of 0 A.D.
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*
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* 0 A.D. is free software: you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation, either version 2 of the License, or
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* (at your option) any later version.
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*
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* 0 A.D. is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with 0 A.D. If not, see <http://www.gnu.org/licenses/>.
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*/
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/*
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* byte order (endianness) support routines.
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*/
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#ifndef INCLUDED_BYTE_ORDER
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#define INCLUDED_BYTE_ORDER
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#include "lib/sysdep/cpu.h"
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// detect byte order via predefined macros.
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#ifndef BYTE_ORDER
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# define LITTLE_ENDIAN 0x4321
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# define BIG_ENDIAN 0x1234
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# if ARCH_IA32 || ARCH_IA64 || ARCH_AMD64 || ARCH_ALPHA || ARCH_ARM || ARCH_MIPS || defined(__LITTLE_ENDIAN__)
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# define BYTE_ORDER LITTLE_ENDIAN
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# else
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# define BYTE_ORDER BIG_ENDIAN
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# endif
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#endif
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/**
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* convert 4 characters to u32 (at compile time) for easy comparison.
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* output is in native byte order; e.g. FOURCC_LE can be used instead.
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**/
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#define FOURCC(a,b,c,d) // real definition is below
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#undef FOURCC
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// implementation rationale:
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// - can't pass code as string, and use s[0]..s[3], because
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// VC6/7 don't realize the macro is constant
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// (it should be usable as a switch{} expression)
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// - the casts are ugly but necessary. u32 is required because u8 << 8 == 0;
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// the additional u8 cast ensures each character is treated as unsigned
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// (otherwise, they'd be promoted to signed int before the u32 cast,
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// which would break things).
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/// big-endian version of FOURCC
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#define FOURCC_BE(a,b,c,d) ( ((u32)(u8)a) << 24 | ((u32)(u8)b) << 16 | \
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((u32)(u8)c) << 8 | ((u32)(u8)d) << 0 )
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/// little-endian version of FOURCC
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#define FOURCC_LE(a,b,c,d) ( ((u32)(u8)a) << 0 | ((u32)(u8)b) << 8 | \
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((u32)(u8)c) << 16 | ((u32)(u8)d) << 24 )
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#if BYTE_ORDER == BIG_ENDIAN
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# define FOURCC FOURCC_BE
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#else
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# define FOURCC FOURCC_LE
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#endif
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/// convert a little-endian number to/from native byte order.
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extern u16 to_le16(u16 x);
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extern u32 to_le32(u32 x); /// see to_le16
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extern u64 to_le64(u64 x); /// see to_le16
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/// convert a big-endian number to/from native byte order.
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extern u16 to_be16(u16 x);
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extern u32 to_be32(u32 x); /// see to_be16
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extern u64 to_be64(u64 x); /// see to_be16
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/// read a little-endian number from memory into native byte order.
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extern u16 read_le16(const void* p);
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extern u32 read_le32(const void* p); /// see read_le16
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extern u64 read_le64(const void* p); /// see read_le16
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/// read a big-endian number from memory into native byte order.
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extern u16 read_be16(const void* p);
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extern u32 read_be32(const void* p); /// see read_be16
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extern u64 read_be64(const void* p); /// see read_be16
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/// write a little-endian number to memory in native byte order.
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extern void write_le16(void* p, u16 x);
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extern void write_le32(void* p, u32 x); /// see write_le16
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extern void write_le64(void* p, u64 x); /// see write_le16
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/// write a big-endian number to memory in native byte order.
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extern void write_be16(void* p, u16 x);
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extern void write_be32(void* p, u32 x); /// see write_be16
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extern void write_be64(void* p, u64 x); /// see write_be16
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/**
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* zero-extend <size> (truncated to 8) bytes of little-endian data to u64,
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* starting at address <p> (need not be aligned).
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**/
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extern u64 movzx_le64(const u8* p, size_t size);
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extern u64 movzx_be64(const u8* p, size_t size);
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/**
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* sign-extend <size> (truncated to 8) bytes of little-endian data to i64,
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* starting at address <p> (need not be aligned).
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**/
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extern i64 movsx_le64(const u8* p, size_t size);
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extern i64 movsx_be64(const u8* p, size_t size);
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#if MSC_VERSION
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extern unsigned short _byteswap_ushort(unsigned short);
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extern unsigned long _byteswap_ulong(unsigned long);
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extern unsigned __int64 _byteswap_uint64(unsigned __int64);
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# if !ICC_VERSION // ICC doesn't need (and warns about) the pragmas
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# pragma intrinsic(_byteswap_ushort)
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# pragma intrinsic(_byteswap_ulong)
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# pragma intrinsic(_byteswap_uint64)
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# endif
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# define swap16 _byteswap_ushort
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# define swap32 _byteswap_ulong
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# define swap64 _byteswap_uint64
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#elif defined(linux)
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# include <asm/byteorder.h>
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# ifdef __arch__swab16
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# define swap16 __arch__swab16
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# endif
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# ifdef __arch__swab32
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# define swap32 __arch__swab32
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# endif
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# ifdef __arch__swab64
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# define swap64 __arch__swab64
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# endif
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#endif
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#ifndef swap16
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extern u16 swap16(const u16 x);
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#endif
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#ifndef swap32
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extern u32 swap32(const u32 x);
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#endif
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#ifndef swap64
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extern u64 swap64(const u64 x);
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#endif
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#endif // #ifndef INCLUDED_BYTE_ORDER
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