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82 lines
1.7 KiB
82 lines
1.7 KiB
/* Bra86.c -- Converter for x86 code (BCJ) |
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2013-11-12 : Igor Pavlov : Public domain */ |
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#include "Precomp.h" |
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#include "Bra.h" |
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#define Test86MSByte(b) ((((b) + 1) & 0xFE) == 0) |
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SizeT x86_Convert(Byte *data, SizeT size, UInt32 ip, UInt32 *state, int encoding) |
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{ |
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SizeT pos = 0; |
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UInt32 mask = *state & 7; |
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if (size < 5) |
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return 0; |
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size -= 4; |
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ip += 5; |
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for (;;) |
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{ |
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Byte *p = data + pos; |
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const Byte *limit = data + size; |
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for (; p < limit; p++) |
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if ((*p & 0xFE) == 0xE8) |
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break; |
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{ |
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SizeT d = (SizeT)(p - data - pos); |
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pos = (SizeT)(p - data); |
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if (p >= limit) |
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{ |
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*state = (d > 2 ? 0 : mask >> (unsigned)d); |
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return pos; |
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} |
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if (d > 2) |
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mask = 0; |
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else |
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{ |
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mask >>= (unsigned)d; |
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if (mask != 0 && (mask > 4 || mask == 3 || Test86MSByte(p[(mask >> 1) + 1]))) |
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{ |
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mask = (mask >> 1) | 4; |
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pos++; |
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continue; |
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} |
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} |
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} |
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if (Test86MSByte(p[4])) |
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{ |
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UInt32 v = ((UInt32)p[4] << 24) | ((UInt32)p[3] << 16) | ((UInt32)p[2] << 8) | ((UInt32)p[1]); |
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UInt32 cur = ip + (UInt32)pos; |
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pos += 5; |
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if (encoding) |
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v += cur; |
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else |
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v -= cur; |
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if (mask != 0) |
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{ |
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unsigned sh = (mask & 6) << 2; |
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if (Test86MSByte((Byte)(v >> sh))) |
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{ |
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v ^= (((UInt32)0x100 << sh) - 1); |
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if (encoding) |
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v += cur; |
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else |
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v -= cur; |
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} |
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mask = 0; |
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} |
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p[1] = (Byte)v; |
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p[2] = (Byte)(v >> 8); |
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p[3] = (Byte)(v >> 16); |
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p[4] = (Byte)(0 - ((v >> 24) & 1)); |
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} |
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else |
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{ |
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mask = (mask >> 1) | 4; |
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pos++; |
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} |
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} |
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}
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