/*BEGIN_LEGAL 
Intel Open Source License 

Copyright (c) 2002-2014 Intel Corporation. All rights reserved.
 
Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions are
met:

Redistributions of source code must retain the above copyright notice,
this list of conditions and the following disclaimer.  Redistributions
in binary form must reproduce the above copyright notice, this list of
conditions and the following disclaimer in the documentation and/or
other materials provided with the distribution.  Neither the name of
the Intel Corporation nor the names of its contributors may be used to
endorse or promote products derived from this software without
specific prior written permission.
 
THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE INTEL OR
ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
END_LEGAL */
/*! @file
 *  An example of Windows application that raises exception and verifies
 *  the FP/XMM state. 
 */
#include <windows.h>
#include <string>
#include <iostream>
#include <memory.h>

using namespace std;

typedef unsigned __int8 UINT8 ;
typedef unsigned __int16 UINT16;
typedef unsigned __int32 UINT32;
typedef unsigned __int64 UINT64;

#if defined(TARGET_IA32)

struct FXSAVE_STRUCT
{
    UINT16 _fcw;
    UINT16 _fsw;
    UINT8  _ftw;
    UINT8  _pad1;
    UINT16 _fop;
    UINT32 _fpuip;
    UINT16 _cs;
    UINT16 _pad2;
    UINT32 _fpudp;
    UINT16 _ds;
    UINT16 _pad3;
    UINT32 _mxcsr;
    UINT32 _mxcsrmask;
    UINT8  _st[8 * 16];
    UINT8  _xmm[8 * 16];
    UINT8  _pad4[56 * 4];
};

struct FPSTATE_STRUCT
{
    // fxsave_legacy is applicable on all IA-32 and Intel(R) 64
    // processors
    struct FXSAVE_STRUCT fxsave_legacy;
    // the following are only applicable on processors with AVX
    UINT8  _header[64];
    UINT8  _ymmUpper[8*16];
    UINT8  _pad5[8*16];
};

typedef FPSTATE_STRUCT FPSTATE;


const size_t FpRegsOffset = offsetof(CONTEXT, FloatSave.RegisterArea);
const size_t FpRegSize = 10;
const size_t NumFpRegs = 8;

const size_t FpRegsOffset2 = (offsetof(CONTEXT, ExtendedRegisters) + offsetof(FPSTATE, fxsave_legacy._st[0]));
const size_t FpRegSize2 = 16;

const size_t XmmRegsOffset = (offsetof(CONTEXT, ExtendedRegisters) + offsetof(FPSTATE, fxsave_legacy._xmm[0]));
const size_t XmmRegSize = 16;
const size_t NumXmmRegs = 8;

#elif defined(TARGET_IA32E)

struct FXSAVE_STRUCT
{
    UINT16 _fcw;
    UINT16 _fsw;
    UINT8  _ftw;
    UINT8  _pad1;
    UINT16 _fop;
    UINT32 _fpuip;
    UINT16 _cs;
    UINT16 _pad2;
    UINT32 _fpudp;
    UINT16 _ds;
    UINT16 _pad3;
    UINT32 _mxcsr;
    UINT32 _mxcsrmask;
    UINT8  _st[8 * 16];
    UINT8  _xmm[16 * 16];
    UINT8  _pad4[24 * 4];
};

struct FPSTATE_STRUCT
{
    // fxsave_legacy is applicable on all IA-32 and Intel(R) 64
    // processors
    struct FXSAVE_STRUCT fxsave_legacy;
    // the following are only applicable on processors with AVX
    UINT8  _header[64];
    UINT8  _ymmUpper[16*16];
};

typedef FPSTATE_STRUCT FPSTATE;
const size_t FpRegsOffset = offsetof(CONTEXT, FltSave.FloatRegisters);
const size_t FpRegSize = 16;
const size_t NumFpRegs = 8;

const size_t XmmRegsOffset = offsetof(CONTEXT, FltSave.XmmRegisters);
const size_t XmmRegSize = 16;
const size_t NumXmmRegs = 16;

#endif


/*!
 * Set some constant values in FP and XMM registers. We set these values before
 * raising the (second) exception and check them in the exception filter using the 
 * CheckMyFpContext() function.
 */
void SetMyFpContext(PCONTEXT pContext)
{
    memset((char *)(pContext) + FpRegsOffset, 0, NumFpRegs*FpRegSize);
    for (size_t i = 0; i < NumFpRegs; ++i)
    {
        *((unsigned char *)(pContext) + FpRegsOffset + (i * FpRegSize)) = (unsigned char)i; 
    }

#if defined(TARGET_IA32)
    memset((char *)(pContext) + FpRegsOffset2, 0, NumFpRegs*FpRegSize2);
    for (size_t i = 0; i < NumFpRegs; ++i)
    {
        *((unsigned char *)(pContext) + FpRegsOffset2 + (i * FpRegSize2)) = (unsigned char)i; 
    }
#endif

    memset((char *)(pContext) + XmmRegsOffset, 0, NumXmmRegs*XmmRegSize);
    for (size_t i = 0; i < NumXmmRegs; ++i)
    {
        *((unsigned char *)(pContext) + XmmRegsOffset + (i * XmmRegSize)) = (unsigned char)i; 
    }
}

/*!
 * Check to see that values of FP/XMM registers in the specified context match
 * values assigned by SetMyFpContext().
 */
static bool CheckMyFpContext(PCONTEXT pContext)
{
    for (size_t i = 0; i < NumFpRegs*FpRegSize; ++i)
    {
        unsigned char regId = i/FpRegSize;

        if ((i%FpRegSize == 0) && 
            (*((unsigned char *)(pContext) + FpRegsOffset + i) != regId))
        {
            return false;
        }
        if ((i%FpRegSize != 0) && 
            (*((unsigned char *)(pContext) + FpRegsOffset + i) != 0))
        {
            return false;
        }
    }

    for (size_t i = 0; i < NumXmmRegs*XmmRegSize; ++i)
    {
        unsigned char regId = i/XmmRegSize;

        if ((i%XmmRegSize == 0) && 
            (*((unsigned char *)(pContext) + XmmRegsOffset + i) != regId))
        {
            return false;
        }
        if ((i%XmmRegSize != 0) && 
            (*((unsigned char *)(pContext) + XmmRegsOffset + i) != 0))
        {
            return false;
        }
    }
    return true;
}

/*!
 * Exception filter. It is invoked twice: 
 * On first exception we set some predefined values in FP and XMM registers and
 * re-raise the exception.
 * On second exception we just return to the exception handler which verifies the
 * the FP/XMM state.
 */
static int MyExceptionFilter(LPEXCEPTION_POINTERS exceptPtr, 
                             PCONTEXT pContext)
{
    static bool first = true;

    if (first)
    {
        first = false;
        SetMyFpContext(exceptPtr->ContextRecord);
        return EXCEPTION_CONTINUE_EXECUTION;
    }
    else
    {
        *pContext = *(exceptPtr->ContextRecord);
        return EXCEPTION_EXECUTE_HANDLER;
    }
}

/*!
 * Exit with the specified error message
 */
static void Abort(const char * msg)
{
    cerr << msg << endl;
    exit(1);
}


/*!
 * The main procedure of the application.
 */
int main(int argc, char *argv[])
{
    CONTEXT context;

    __try
    {
        char * p = 0;
        p++;
        *p = 0;
    }
    __except (MyExceptionFilter(GetExceptionInformation(), &context))
    {
        if (!CheckMyFpContext(&context))
        {
            Abort("Mismatch in the FP context");
        }
    }
    
    cerr << "Success" << endl;
    return 0;
}
