/**************************************************************************
 * 
 * Copyright 2008 Tungsten Graphics, Inc., Cedar Park, Texas.
 * All Rights Reserved.
 * 
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the
 * "Software"), to deal in the Software without restriction, including
 * without limitation the rights to use, copy, modify, merge, publish,
 * distribute, sub license, and/or sell copies of the Software, and to
 * permit persons to whom the Software is furnished to do so, subject to
 * the following conditions:
 * 
 * The above copyright notice and this permission notice (including the
 * next paragraph) shall be included in all copies or substantial portions
 * of the Software.
 * 
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
 * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT.
 * IN NO EVENT SHALL TUNGSTEN GRAPHICS AND/OR ITS SUPPLIERS BE LIABLE FOR
 * ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
 * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
 * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 * 
 **************************************************************************/

/**
 * @file
 * Poor-man profiling.
 * 
 * @author José Fonseca <jrfonseca@tungstengraphics.com>
 * 
 * @sa http://blogs.msdn.com/joshpoley/archive/2008/03/12/poor-man-s-profiler.aspx
 * @sa http://www.johnpanzer.com/aci_cuj/index.html
 */

#include "pipe/p_config.h" 

#if defined(PROFILE) && defined(PIPE_SUBSYSTEM_WINDOWS_DISPLAY)

#include <windows.h>
#include <winddi.h>

#include "pipe/p_debug.h" 
#include "util/u_string.h" 


#define PROFILE_FILE_SIZE 4*1024*1024
#define FILE_NAME_SIZE 256

static WCHAR wFileName[FILE_NAME_SIZE];
static ULONG_PTR iFile = 0;
static void *pMap = NULL;
static void *pMapEnd = NULL;


/**
 * Called at the start of every method or function.
 * 
 * @sa http://msdn.microsoft.com/en-us/library/c63a9b7h.aspx
 */
void __declspec(naked) __cdecl 
_penter(void) {
   _asm {
      push ebx
      mov ebx, [pMap]
      test ebx, ebx
      jz done
      cmp ebx, [pMapEnd]
      je done
      push eax
      push edx
      mov eax, [esp+12]
      and eax, 0xfffffffe
      mov [ebx], eax
      add ebx, 4
      rdtsc
      mov [ebx], eax
      add ebx, 4
      mov [pMap], ebx
      pop edx
      pop eax
done:
      pop ebx
      ret  
   }
}


/**
 * Called at the end of Calls the end of every method or function.
 * 
 * @sa http://msdn.microsoft.com/en-us/library/xc11y76y.aspx
 */
void __declspec(naked) __cdecl 
_pexit(void) {
   _asm {
      push ebx
      mov ebx, [pMap]
      test ebx, ebx
      jz done
      cmp ebx, [pMapEnd]
      je done
      push eax
      push edx
      mov eax, [esp+12]
      or eax, 0x00000001
      mov [ebx], eax
      add ebx, 4
      rdtsc
      mov [ebx], eax
      add ebx, 4
      mov [pMap], ebx
      pop edx
      pop eax
done:
      pop ebx
      ret
   }
}


void __declspec(naked) 
__debug_profile_reference1(void) {
   _asm {
      call _penter
      call _pexit
      ret
   }
}


void __declspec(naked) 
__debug_profile_reference2(void) {
   _asm {
      call _penter
      call __debug_profile_reference1
      call _pexit
      ret
   }
}


void
debug_profile_start(void)
{
   static unsigned no = 0; 
   char filename[FILE_NAME_SIZE];
   unsigned i;

   util_snprintf(filename, sizeof(filename), "\\??\\c:\\%03u.prof", ++no);
   for(i = 0; i < FILE_NAME_SIZE; ++i)
      wFileName[i] = (WCHAR)filename[i];
   
   pMap = EngMapFile(wFileName, PROFILE_FILE_SIZE, &iFile);
   if(pMap) {
      pMapEnd = (unsigned char*)pMap + PROFILE_FILE_SIZE;
      /* reference functions for calibration purposes */
      __debug_profile_reference2();
   }
}

void 
debug_profile_stop(void)
{
   if(iFile) {
      EngUnmapFile(iFile);
      /* TODO: truncate file */
   }
   iFile = 0;
   pMapEnd = pMap = NULL; 
}

#endif /* PROFILE */