// Copyright 2002 Ben Rudiak-Gould et al.
// http://www.avisynth.org

// This program is free software; you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation; either version 2 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program; if not, write to the Free Software
// Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA, or visit
// http://www.gnu.org/copyleft/gpl.html .
//
// Linking Avisynth statically or dynamically with other modules is making a
// combined work based on Avisynth.  Thus, the terms and conditions of the GNU
// General Public License cover the whole combination.
//
// As a special exception, the copyright holders of Avisynth give you
// permission to link Avisynth with independent modules that communicate with
// Avisynth solely through the interfaces defined in avisynth.h, regardless of the license
// terms of these independent modules, and to copy and distribute the
// resulting combined work under terms of your choice, provided that
// every copy of the combined work is accompanied by a complete copy of
// the source code of Avisynth (the version of Avisynth used to produce the
// combined work), being distributed under the terms of the GNU General
// Public License plus this exception.  An independent module is a module
// which is not derived from or based on Avisynth, such as 3rd-party filters,
// import and export plugins, or graphical user interfaces.

static int C_scenechange_16(const BYTE* c_plane, const BYTE* tplane, int height, int width, int c_pitch, int t_pitch) {
  unsigned int accum = 0;
  for (int y = 0; y < height; y++) {
    for (int x = 0; x < width; x++) {
      accum += abs(tplane[x] - c_plane[x]);
    }
    c_plane += c_pitch;
    tplane += t_pitch;
  }
  return accum;

}

/*********************
 * YV12 Scenechange detection.
 * 
 * (c) 2003, Klaus Post
 *
 * ISSE, MOD 16 version.
 *
 * Returns an int of the accumulated absolute difference
 * between two planes. 
 *
 * The absolute difference between two planes are returned as an int.
 * This version is optimized for mod16 widths. Others widths are allowed, 
 *  but the remaining pixels are simply skipped.
 *********************/


static int isse_scenechange_16(const BYTE* c_plane, const BYTE* tplane, int height, int width, int c_pitch, int t_pitch) {
  int wp=width;
  int hp=height;
  int returnvalue=0xbadbad00;
  __asm {
    xor ebx,ebx     // Height
    pxor mm5,mm5  // Maximum difference
    mov edx, c_pitch    //copy pitch
    mov ecx, t_pitch    //copy pitch
    pxor mm6,mm6   // We maintain two sums, for better pairablility
    pxor mm7,mm7
    mov esi, c_plane
    mov edi, tplane
    jmp yloopover
    align 16
yloop:
    inc ebx
    add edi,ecx     // add pitch to both planes
    add esi,edx
yloopover:
    cmp ebx,[hp]
    jge endframe
    xor eax,eax     // Width
    align 16
xloop:
    cmp eax,[wp]    
    jge yloop

    movq mm0,[esi+eax]
     movq mm2,[esi+eax+8]
    movq mm1,[edi+eax]
     movq mm3,[edi+eax+8]
    psadbw mm0,mm1    // Sum of absolute difference
     psadbw mm2,mm3
    paddd mm6,mm0     // Add...
     paddd mm7,mm2

    add eax,16
    jmp xloop
endframe:
    paddd mm7,mm6
    movd returnvalue,mm7
    emms
  }
  return returnvalue;
}