2006-04-24 01:14:18 +02:00
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/**
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* =========================================================================
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* File : byte_order.cpp
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* Project : 0 A.D.
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* Description : byte order (endianness) support routines.
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* =========================================================================
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*/
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2007-05-07 18:33:24 +02:00
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// license: GPL; see lib/license.txt
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2006-04-24 01:14:18 +02:00
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#include "precompiled.h"
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#include "byte_order.h"
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2007-05-09 23:01:11 +02:00
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#include "bits.h"
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2006-04-24 01:14:18 +02:00
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2007-01-01 22:25:47 +01:00
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#ifndef swap16
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u16 swap16(const u16 x)
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{
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return (u16)(((x & 0xff) << 8) | (x >> 8));
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}
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u32 swap32(const u32 x)
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{
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return (x << 24) |
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(x >> 24) |
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((x << 8) & 0x00ff0000) |
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((x >> 8) & 0x0000ff00);
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}
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u64 swap64(const u64 x)
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{
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const u32 lo = (u32)(x & 0xFFFFFFFF);
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const u32 hi = (u32)(x >> 32);
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u64 ret = swap32(lo);
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ret <<= 32;
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// careful: must shift var of type u64, not u32
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ret |= swap32(hi);
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return ret;
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}
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#endif // #ifndef swap16
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//-----------------------------------------------------------------------------
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2006-04-24 01:14:18 +02:00
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u16 to_le16(u16 x)
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{
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2007-01-01 22:25:47 +01:00
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#if BYTE_ORDER == BIG_ENDIAN
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return swap16(x);
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2006-04-24 01:14:18 +02:00
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#else
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return x;
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#endif
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}
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u32 to_le32(u32 x)
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{
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2007-01-01 22:25:47 +01:00
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#if BYTE_ORDER == BIG_ENDIAN
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return swap32(x);
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2006-04-24 01:14:18 +02:00
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#else
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return x;
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#endif
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}
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u64 to_le64(u64 x)
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{
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2007-01-01 22:25:47 +01:00
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#if BYTE_ORDER == BIG_ENDIAN
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return swap64(x);
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2006-04-24 01:14:18 +02:00
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#else
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return x;
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#endif
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}
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u16 to_be16(u16 x)
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{
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2007-01-01 22:25:47 +01:00
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#if BYTE_ORDER == BIG_ENDIAN
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2006-04-24 01:14:18 +02:00
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return x;
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#else
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2007-01-01 22:25:47 +01:00
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return swap16(x);
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2006-04-24 01:14:18 +02:00
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#endif
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}
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u32 to_be32(u32 x)
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{
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2007-01-01 22:25:47 +01:00
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#if BYTE_ORDER == BIG_ENDIAN
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2006-04-24 01:14:18 +02:00
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return x;
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#else
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2007-01-01 22:25:47 +01:00
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return swap32(x);
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2006-04-24 01:14:18 +02:00
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#endif
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}
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u64 to_be64(u64 x)
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{
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2007-01-01 22:25:47 +01:00
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#if BYTE_ORDER == BIG_ENDIAN
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2006-04-24 01:14:18 +02:00
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return x;
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#else
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2007-01-01 22:25:47 +01:00
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return swap64(x);
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2006-04-24 01:14:18 +02:00
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#endif
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}
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u16 read_le16(const void* p)
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{
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return to_le16(*(u16*)p);
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}
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u32 read_le32(const void* p)
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{
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return to_le32(*(u32*)p);
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}
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u64 read_le64(const void* p)
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{
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return to_le64(*(u64*)p);
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}
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u16 read_be16(const void* p)
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{
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return to_be16(*(u16*)p);
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}
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u32 read_be32(const void* p)
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{
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return to_be32(*(u32*)p);
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}
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u64 read_be64(const void* p)
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{
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return to_be64(*(u64*)p);
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}
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void write_le16(void* p, u16 x)
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{
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*(u16*)p = to_le16(x);
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}
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void write_le32(void* p, u32 x)
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{
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*(u32*)p = to_le32(x);
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}
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void write_le64(void* p, u64 x)
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{
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*(u64*)p = to_le64(x);
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}
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void write_be16(void* p, u16 x)
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{
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*(u16*)p = to_be16(x);
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}
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void write_be32(void* p, u32 x)
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{
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*(u32*)p = to_be32(x);
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}
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void write_be64(void* p, u64 x)
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{
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*(u64*)p = to_be64(x);
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}
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2007-05-09 23:01:11 +02:00
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u64 movzx_le64(const u8* p, size_t size_bytes)
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{
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u64 number = 0;
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2007-05-17 05:37:49 +02:00
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for(uint i = 0; i < std::min(size_bytes, (size_t)8u); i++)
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2007-05-09 23:01:11 +02:00
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number |= ((u64)p[i]) << (i*8);
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return number;
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}
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u64 movzx_be64(const u8* p, size_t size_bytes)
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{
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u64 number = 0;
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2007-05-17 05:37:49 +02:00
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for(uint i = 0; i < std::min(size_bytes, (size_t)8u); i++)
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2007-05-09 23:01:11 +02:00
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{
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number <<= 8;
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number |= p[i];
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}
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return number;
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}
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static inline i64 SignExtend(u64 bits, size_t size_bytes)
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{
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// no point in sign-extending if >= 8 bytes were requested
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if(size_bytes < 8)
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{
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const u64 sign_bit = BIT64((size_bytes*8)-1);
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// number would be negative in the smaller type,
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// so sign-extend, i.e. set all more significant bits.
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if(bits & sign_bit)
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{
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const u64 valid_bit_mask = (sign_bit+sign_bit)-1;
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bits |= ~valid_bit_mask;
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}
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}
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const i64 number = static_cast<i64>(bits);
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return number;
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}
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i64 movsx_le64(const u8* p, size_t size_bytes)
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{
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const u64 number = movzx_le64(p, size_bytes);
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return SignExtend(number, size_bytes);
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}
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i64 movsx_be64(const u8* p, size_t size_bytes)
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{
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const u64 number = movzx_be64(p, size_bytes);
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return SignExtend(number, size_bytes);
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}
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