/* BraIA64.c -- Converter for IA-64 code
2013-11-12 : Igor Pavlov : Public domain */

#include "Precomp.h"

#include "Bra.h"

static const Byte kBranchTable[32] =
{
  0, 0, 0, 0, 0, 0, 0, 0,
  0, 0, 0, 0, 0, 0, 0, 0,
  4, 4, 6, 6, 0, 0, 7, 7,
  4, 4, 0, 0, 4, 4, 0, 0
};

SizeT IA64_Convert(Byte* data, SizeT size, UInt32 ip, int encoding)
{
    SizeT i;
    if (size < 16)
        return 0;
    size -= 16;
    for (i = 0; i <= size; i += 16)
    {
        UInt32 instrTemplate = data[i] & 0x1F;
        UInt32 mask = kBranchTable[instrTemplate];
        UInt32 bitPos = 5;
        int slot;
        for (slot = 0; slot < 3; slot++, bitPos += 41)
        {
            UInt32 bytePos, bitRes;
            UInt64 instruction, instNorm;
            int j;
            if (((mask >> slot) & 1) == 0)
                continue;
            bytePos = (bitPos >> 3);
            bitRes = bitPos & 0x7;
            instruction = 0;
            for (j = 0; j < 6; j++)
                instruction += (UInt64)data[i + j + bytePos] << (8 * j);

            instNorm = instruction >> bitRes;
            if (((instNorm >> 37) & 0xF) == 0x5 && ((instNorm >> 9) & 0x7) == 0)
            {
                UInt32 src = (UInt32)((instNorm >> 13) & 0xFFFFF);
                UInt32 dest;
                src |= ((UInt32)(instNorm >> 36) & 1) << 20;

                src <<= 4;

                if (encoding)
                    dest = ip + (UInt32)i + src;
                else
                    dest = src - (ip + (UInt32)i);

                dest >>= 4;

                instNorm &= ~((UInt64)(0x8FFFFF) << 13);
                instNorm |= ((UInt64)(dest & 0xFFFFF) << 13);
                instNorm |= ((UInt64)(dest & 0x100000) << (36 - 20));

                instruction &= (1 << bitRes) - 1;
                instruction |= (instNorm << bitRes);
                for (j = 0; j < 6; j++)
                    data[i + j + bytePos] = (Byte)(instruction >> (8 * j));
            }
        }
    }
    return i;
}
