PeerStreamer

/*

 * GMC (Global Motion Compensation)

 * AltiVec-enabled

 * Copyright (c) 2003 Romain Dolbeau <romain@dolbeau.org>

 *

 * This library is free software; you can redistribute it and/or

 * modify it under the terms of the GNU Lesser General Public

 * License as published by the Free Software Foundation; either

 * version 2 of the License, or (at your option) any later version.

 *

 * This library 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

 * Lesser General Public License for more details.

 *

 * You should have received a copy of the GNU Lesser General Public

 * License along with this library; if not, write to the Free Software

 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA

 */

#include "../dsputil.h"

#include "gcc_fixes.h"

#include "dsputil_altivec.h"

/*

  altivec-enhanced gmc1. ATM this code assume stride is a multiple of 8,

  to preserve proper dst alignement.

*/

#define GMC1_PERF_COND (h==8)

void gmc1_altivec(uint8_t *dst /* align 8 */, uint8_t *src /* align1 */, int stride, int h, int x16, int y16, int rounder)

{

POWERPC_PERF_DECLARE(altivec_gmc1_num, GMC1_PERF_COND);

#ifdef ALTIVEC_USE_REFERENCE_C_CODE

    const int A=(16-x16)*(16-y16);

    const int B=(   x16)*(16-y16);

    const int C=(16-x16)*(   y16);

    const int D=(   x16)*(   y16);

    int i;

POWERPC_PERF_START_COUNT(altivec_gmc1_num, GMC1_PERF_COND);

    for(i=0; i<h; i++)

    {

        dst[0]= (A*src[0] + B*src[1] + C*src[stride+0] + D*src[stride+1] + rounder)>>8;

        dst[1]= (A*src[1] + B*src[2] + C*src[stride+1] + D*src[stride+2] + rounder)>>8;

        dst[2]= (A*src[2] + B*src[3] + C*src[stride+2] + D*src[stride+3] + rounder)>>8;

        dst[3]= (A*src[3] + B*src[4] + C*src[stride+3] + D*src[stride+4] + rounder)>>8;

        dst[4]= (A*src[4] + B*src[5] + C*src[stride+4] + D*src[stride+5] + rounder)>>8;

        dst[5]= (A*src[5] + B*src[6] + C*src[stride+5] + D*src[stride+6] + rounder)>>8;

        dst[6]= (A*src[6] + B*src[7] + C*src[stride+6] + D*src[stride+7] + rounder)>>8;

        dst[7]= (A*src[7] + B*src[8] + C*src[stride+7] + D*src[stride+8] + rounder)>>8;

        dst+= stride;

        src+= stride;

    }

POWERPC_PERF_STOP_COUNT(altivec_gmc1_num, GMC1_PERF_COND);

#else /* ALTIVEC_USE_REFERENCE_C_CODE */

    const unsigned short __attribute__ ((aligned(16))) rounder_a[8] =

      {rounder, rounder, rounder, rounder,

       rounder, rounder, rounder, rounder};

    const unsigned short __attribute__ ((aligned(16))) ABCD[8] =

      {

        (16-x16)*(16-y16), /* A */

        (   x16)*(16-y16), /* B */

        (16-x16)*(   y16), /* C */

        (   x16)*(   y16), /* D */

        0, 0, 0, 0         /* padding */

      };

    register const_vector unsigned char vczero = (const_vector unsigned char)vec_splat_u8(0);

    register const_vector unsigned short vcsr8 = (const_vector unsigned short)vec_splat_u16(8);

    register vector unsigned char dstv, dstv2, src_0, src_1, srcvA, srcvB, srcvC, srcvD;

    register vector unsigned short Av, Bv, Cv, Dv, rounderV, tempA, tempB, tempC, tempD;

    int i;

    unsigned long dst_odd = (unsigned long)dst & 0x0000000F;

    unsigned long src_really_odd = (unsigned long)src & 0x0000000F;

POWERPC_PERF_START_COUNT(altivec_gmc1_num, GMC1_PERF_COND);

    tempA = vec_ld(0, (unsigned short*)ABCD);

    Av = vec_splat(tempA, 0);

    Bv = vec_splat(tempA, 1);

    Cv = vec_splat(tempA, 2);

    Dv = vec_splat(tempA, 3);

    rounderV = vec_ld(0, (unsigned short*)rounder_a);

    // we'll be able to pick-up our 9 char elements

    // at src from those 32 bytes

    // we load the first batch here, as inside the loop

    // we can re-use 'src+stride' from one iteration

    // as the 'src' of the next.

    src_0 = vec_ld(0, src);

    src_1 = vec_ld(16, src);

    srcvA = vec_perm(src_0, src_1, vec_lvsl(0, src));

    if (src_really_odd != 0x0000000F)

    { // if src & 0xF == 0xF, then (src+1) is properly aligned on the second vector.

      srcvB = vec_perm(src_0, src_1, vec_lvsl(1, src));

    }

    else

    {

      srcvB = src_1;

    }

    srcvA = vec_mergeh(vczero, srcvA);

    srcvB = vec_mergeh(vczero, srcvB);

    for(i=0; i<h; i++)

    {

      dst_odd = (unsigned long)dst & 0x0000000F;

      src_really_odd = (((unsigned long)src) + stride) & 0x0000000F;

      dstv = vec_ld(0, dst);

      // we we'll be able to pick-up our 9 char elements

      // at src + stride from those 32 bytes

      // then reuse the resulting 2 vectors srvcC and srcvD

      // as the next srcvA and srcvB

      src_0 = vec_ld(stride + 0, src);

      src_1 = vec_ld(stride + 16, src);

      srcvC = vec_perm(src_0, src_1, vec_lvsl(stride + 0, src));

      if (src_really_odd != 0x0000000F)

      { // if src & 0xF == 0xF, then (src+1) is properly aligned on the second vector.

        srcvD = vec_perm(src_0, src_1, vec_lvsl(stride + 1, src));

      }

      else

      {

        srcvD = src_1;

      }

      srcvC = vec_mergeh(vczero, srcvC);

      srcvD = vec_mergeh(vczero, srcvD);

      // OK, now we (finally) do the math :-)

      // those four instructions replaces 32 int muls & 32 int adds.

      // isn't AltiVec nice ?

      tempA = vec_mladd((vector unsigned short)srcvA, Av, rounderV);

      tempB = vec_mladd((vector unsigned short)srcvB, Bv, tempA);

      tempC = vec_mladd((vector unsigned short)srcvC, Cv, tempB);

      tempD = vec_mladd((vector unsigned short)srcvD, Dv, tempC);

      srcvA = srcvC;

      srcvB = srcvD;

      tempD = vec_sr(tempD, vcsr8);

      dstv2 = vec_pack(tempD, (vector unsigned short)vczero);

      if (dst_odd)

      {

        dstv2 = vec_perm(dstv, dstv2, vcprm(0,1,s0,s1));

      }

      else

      {

        dstv2 = vec_perm(dstv, dstv2, vcprm(s0,s1,2,3));

      }

      vec_st(dstv2, 0, dst);

      dst += stride;

      src += stride;

    }

POWERPC_PERF_STOP_COUNT(altivec_gmc1_num, GMC1_PERF_COND);

#endif /* ALTIVEC_USE_REFERENCE_C_CODE */

}