/*
*
* mblock_sub44_sads_x86_h.c
* Copyright (C) 2000 Andrew Stevens
*
* Fast block sum-absolute difference computation for a rectangular area 4*x
* by y where y > h against a 4 by h block.
*
* Used for 4*4 sub-sampled motion compensation calculations.
*
*
* This file is part of mpeg2enc, a free MPEG-2 video stream encoder
* based on the original MSSG reference design
*
* mpeg2enc is free software; you can redistribute new parts
* and/or modify 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.
*
* mpeg2enc 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.
*
* See the files for those sections (c) MSSG
*
* 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., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
/*
*
* Generates a vector sad's for 4*4 sub-sampled pel (qpel) data (with
* co-ordinates and top-left qpel address) from specified rectangle
* against a specified 16*h pel (4*4 qpel) reference block. The
* generated vector contains results only for those sad's that fall
* below twice the running best sad and are aligned on 8-pel
* boundaries
*
* Invariant: blk points to top-left sub-sampled pel for macroblock
* at (ilow,ihigh)
* i{low,high) j(low,high) must be multiples of 4.
*
* sad = Sum Absolute Differences
*
* NOTES: for best efficiency i{low,high) should be multiples of 16.
*
* */
int SIMD_SUFFIX(mblock_sub44_dists)( uint8_t *blk, uint8_t *ref,
int ilow,int jlow,
int ihigh, int jhigh,
int h, int rowstride,
int threshold,
mc_result_s *resvec)
{
int32_t x,y;
uint8_t *currowblk = blk;
uint8_t *curblk;
mc_result_s *cres = resvec;
int gridrowstride = (rowstride);
for( y=jlow; y <= jhigh ; y+=4)
{
curblk = currowblk;
for( x = ilow; x <= ihigh; x += 4)
{
int weight;
if( (x & 15) == (ilow & 15) )
{
load_blk( curblk, rowstride, h );
}
weight = SIMD_SUFFIX(qblock_sad)(ref, h, rowstride);
if( weight <= threshold )
{
threshold = intmin(weight<<2,threshold);
/* Rough and-ready absolute distance penalty */
/* NOTE: This penalty is *vital* to correct operation
as otherwise the sub-mean filtering won't work on very
uniform images.
*/
cres->weight = (uint16_t)weight+((intabs(x)+intabs(y))>>3);
cres->x = (uint8_t)x;
cres->y = (uint8_t)y;
++cres;
}
curblk += 1;
shift_blk(8);
}
currowblk += gridrowstride;
}
emms();
return cres - resvec;
}
#undef concat