FFmpeg/libavcodec/libpostproc/postprocess_altivec_template.c

/*
    AltiVec optimizations (C) 2004 Romain Dolbeau <romain@dolbeau.org>

    based on code by Copyright (C) 2001-2003 Michael Niedermayer (michaelni@gmx.at)

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


#ifdef CONFIG_DARWIN
#define AVV(x...) (x)
#else
#define AVV(x...) {x}
#endif

#define ALTIVEC_TRANSPOSE_8x8_SHORT(src_a,src_b,src_c,src_d,src_e,src_f,src_g,src_h) \
  do {                                                                  \
    __typeof__(src_a) tempA1, tempB1, tempC1, tempD1;                   \
    __typeof__(src_a) tempE1, tempF1, tempG1, tempH1;                   \
    __typeof__(src_a) tempA2, tempB2, tempC2, tempD2;                   \
    __typeof__(src_a) tempE2, tempF2, tempG2, tempH2;                   \
    tempA1 = vec_mergeh (src_a, src_e);                                 \
    tempB1 = vec_mergel (src_a, src_e);                                 \
    tempC1 = vec_mergeh (src_b, src_f);                                 \
    tempD1 = vec_mergel (src_b, src_f);                                 \
    tempE1 = vec_mergeh (src_c, src_g);                                 \
    tempF1 = vec_mergel (src_c, src_g);                                 \
    tempG1 = vec_mergeh (src_d, src_h);                                 \
    tempH1 = vec_mergel (src_d, src_h);                                 \
    tempA2 = vec_mergeh (tempA1, tempE1);                               \
    tempB2 = vec_mergel (tempA1, tempE1);                               \
    tempC2 = vec_mergeh (tempB1, tempF1);                               \
    tempD2 = vec_mergel (tempB1, tempF1);                               \
    tempE2 = vec_mergeh (tempC1, tempG1);                               \
    tempF2 = vec_mergel (tempC1, tempG1);                               \
    tempG2 = vec_mergeh (tempD1, tempH1);                               \
    tempH2 = vec_mergel (tempD1, tempH1);                               \
    src_a = vec_mergeh (tempA2, tempE2);                                \
    src_b = vec_mergel (tempA2, tempE2);                                \
    src_c = vec_mergeh (tempB2, tempF2);                                \
    src_d = vec_mergel (tempB2, tempF2);                                \
    src_e = vec_mergeh (tempC2, tempG2);                                \
    src_f = vec_mergel (tempC2, tempG2);                                \
    src_g = vec_mergeh (tempD2, tempH2);                                \
    src_h = vec_mergel (tempD2, tempH2);                                \
  } while (0)


static inline int vertClassify_altivec(uint8_t src[], int stride, PPContext *c) {
  /*
    this code makes no assumption on src or stride.
    One could remove the recomputation of the perm
    vector by assuming (stride % 16) == 0, unfortunately
    this is not always true.
  */
  register int y;
  short __attribute__ ((aligned(16))) data[8];
  int numEq;
  uint8_t *src2 = src;
  vector signed short v_dcOffset;
  vector signed short v2QP;
  vector unsigned short v4QP;
  vector unsigned short v_dcThreshold;
  const int properStride = (stride % 16);
  const int srcAlign = ((unsigned long)src2 % 16);
  const int two_vectors = ((srcAlign > 8) || properStride) ? 1 : 0;
  const vector signed int zero = vec_splat_s32(0);
  const vector signed short mask = vec_splat_s16(1);
  vector signed int v_numEq = vec_splat_s32(0);

  data[0] = ((c->nonBQP*c->ppMode.baseDcDiff)>>8) + 1;
  data[1] = data[0] * 2 + 1;
  data[2] = c->QP * 2;
  data[3] = c->QP * 4;
  vector signed short v_data = vec_ld(0, data);
  v_dcOffset = vec_splat(v_data, 0);
  v_dcThreshold = (vector unsigned short)vec_splat(v_data, 1);
  v2QP = vec_splat(v_data, 2);
  v4QP = (vector unsigned short)vec_splat(v_data, 3);

  src2 += stride * 4;

  vector signed short v_srcAss0, v_srcAss1, v_srcAss2, v_srcAss3, v_srcAss4, v_srcAss5, v_srcAss6, v_srcAss7;

#define LOAD_LINE(i)                                                    \
  register int j##i = i * stride;                                       \
  vector unsigned char perm##i = vec_lvsl(j##i, src2);                  \
  const vector unsigned char v_srcA1##i = vec_ld(j##i, src2);           \
  vector unsigned char v_srcA2##i;                                      \
  if (two_vectors)                                                      \
    v_srcA2##i = vec_ld(j##i + 16, src2);                               \
  const vector unsigned char v_srcA##i =                                \
    vec_perm(v_srcA1##i, v_srcA2##i, perm##i);                          \
  v_srcAss##i =                                                         \
    (vector signed short)vec_mergeh((vector signed char)zero,           \
                                    (vector signed char)v_srcA##i)

#define LOAD_LINE_ALIGNED(i)                                            \
  register int j##i = i * stride;                                       \
  const vector unsigned char v_srcA##i = vec_ld(j##i, src2);            \
  v_srcAss##i =                                                         \
    (vector signed short)vec_mergeh((vector signed char)zero,           \
                                    (vector signed char)v_srcA##i)

    // special casing the aligned case is worthwhile, as all call from
    // the (transposed) horizontable deblocks will be aligned, i naddition
    // to the naturraly aligned vertical deblocks.
    if (properStride && srcAlign) {
      LOAD_LINE_ALIGNED(0);
      LOAD_LINE_ALIGNED(1);
      LOAD_LINE_ALIGNED(2);
      LOAD_LINE_ALIGNED(3);
      LOAD_LINE_ALIGNED(4);
      LOAD_LINE_ALIGNED(5);
      LOAD_LINE_ALIGNED(6);
      LOAD_LINE_ALIGNED(7);
    } else {
      LOAD_LINE(0);
      LOAD_LINE(1);
      LOAD_LINE(2);
      LOAD_LINE(3);
      LOAD_LINE(4);
      LOAD_LINE(5);
      LOAD_LINE(6);
      LOAD_LINE(7);
    }
#undef LOAD_LINE
#undef LOAD_LINE_ALIGNED

#define ITER(i, j)                                                      \
  const vector signed short v_diff##i =                                 \
    vec_sub(v_srcAss##i, v_srcAss##j);                                  \
  const vector signed short v_sum##i =                                  \
    vec_add(v_diff##i, v_dcOffset);                                     \
  const vector signed short v_comp##i =                                 \
    (vector signed short)vec_cmplt((vector unsigned short)v_sum##i,     \
                                   v_dcThreshold);                      \
  const vector signed short v_part##i = vec_and(mask, v_comp##i);       \
  v_numEq = vec_sum4s(v_part##i, v_numEq);

  ITER(0, 1);
  ITER(1, 2);
  ITER(2, 3);
  ITER(3, 4);
  ITER(4, 5);
  ITER(5, 6);
  ITER(6, 7);
#undef ITER

  v_numEq = vec_sums(v_numEq, zero);

  v_numEq = vec_splat(v_numEq, 3);
  vec_ste(v_numEq, 0, &numEq);

  if (numEq > c->ppMode.flatnessThreshold)
    {
      const vector unsigned char mmoP1 = (const vector unsigned char)
        AVV(0x1f, 0x1f, 0x1f, 0x1f, 0x1f, 0x1f, 0x1f, 0x1f,
            0x00, 0x01, 0x12, 0x13, 0x08, 0x09, 0x1A, 0x1B);
      const vector unsigned char mmoP2 = (const vector unsigned char)
        AVV(0x04, 0x05, 0x16, 0x17, 0x0C, 0x0D, 0x1E, 0x1F,
            0x1f, 0x1f, 0x1f, 0x1f, 0x1f, 0x1f, 0x1f, 0x1f);
      const vector unsigned char mmoP = (const vector unsigned char)
        vec_lvsl(8, (unsigned char*)0);

      vector signed short mmoL1 = vec_perm(v_srcAss0, v_srcAss2, mmoP1);
      vector signed short mmoL2 = vec_perm(v_srcAss4, v_srcAss6, mmoP2);
      vector signed short mmoL = vec_perm(mmoL1, mmoL2, mmoP);
      vector signed short mmoR1 = vec_perm(v_srcAss5, v_srcAss7, mmoP1);
      vector signed short mmoR2 = vec_perm(v_srcAss1, v_srcAss3, mmoP2);
      vector signed short mmoR = vec_perm(mmoR1, mmoR2, mmoP);
      vector signed short mmoDiff = vec_sub(mmoL, mmoR);
      vector unsigned short mmoSum = (vector unsigned short)vec_add(mmoDiff, v2QP);

      if (vec_any_gt(mmoSum, v4QP))
        return 0;
      else
        return 1;
    }
  else return 2;
}

static inline void doVertLowPass_altivec(uint8_t *src, int stride, PPContext *c) {
  /*
    this code makes no assumption on src or stride.
    One could remove the recomputation of the perm
    vector by assuming (stride % 16) == 0, unfortunately
    this is not always true. Quite a lot of load/stores
    can be removed by assuming proper alignement of
    src & stride :-(
  */
  uint8_t *src2 = src;
  const vector signed int zero = vec_splat_s32(0);
  const int properStride = (stride % 16);
  const int srcAlign = ((unsigned long)src2 % 16);
  short __attribute__ ((aligned(16))) qp[8];
  qp[0] = c->QP;
  vector signed short vqp = vec_ld(0, qp);
  vqp = vec_splat(vqp, 0);

  src2 += stride*3;

  vector signed short vb0, vb1, vb2, vb3, vb4, vb5, vb6, vb7, vb8, vb9;
  vector unsigned char vbA0, vbA1, vbA2, vbA3, vbA4, vbA5, vbA6, vbA7, vbA8, vbA9;
  vector unsigned char vbB0, vbB1, vbB2, vbB3, vbB4, vbB5, vbB6, vbB7, vbB8, vbB9;
  vector unsigned char vbT0, vbT1, vbT2, vbT3, vbT4, vbT5, vbT6, vbT7, vbT8, vbT9;

#define LOAD_LINE(i)                                                    \
  const vector unsigned char perml##i =                                 \
    vec_lvsl(i * stride, src2);                                         \
  vbA##i = vec_ld(i * stride, src2);                                    \
  vbB##i = vec_ld(i * stride + 16, src2);                               \
  vbT##i = vec_perm(vbA##i, vbB##i, perml##i);                          \
  vb##i =                                                               \
    (vector signed short)vec_mergeh((vector unsigned char)zero,         \
                                    (vector unsigned char)vbT##i)

#define LOAD_LINE_ALIGNED(i)                                            \
  register int j##i = i * stride;                                       \
  vbT##i = vec_ld(j##i, src2);                                          \
  vb##i =                                                               \
    (vector signed short)vec_mergeh((vector signed char)zero,           \
                                    (vector signed char)vbT##i)

    // special casing the aligned case is worthwhile, as all call from
    // the (transposed) horizontable deblocks will be aligned, in addition
    // to the naturraly aligned vertical deblocks.
    if (properStride && srcAlign) {
      LOAD_LINE_ALIGNED(0);
      LOAD_LINE_ALIGNED(1);
      LOAD_LINE_ALIGNED(2);
      LOAD_LINE_ALIGNED(3);
      LOAD_LINE_ALIGNED(4);
      LOAD_LINE_ALIGNED(5);
      LOAD_LINE_ALIGNED(6);
      LOAD_LINE_ALIGNED(7);
      LOAD_LINE_ALIGNED(8);
      LOAD_LINE_ALIGNED(9);
    } else {
      LOAD_LINE(0);
      LOAD_LINE(1);
      LOAD_LINE(2);
      LOAD_LINE(3);
      LOAD_LINE(4);
      LOAD_LINE(5);
      LOAD_LINE(6);
      LOAD_LINE(7);
      LOAD_LINE(8);
      LOAD_LINE(9);
    }
#undef LOAD_LINE
#undef LOAD_LINE_ALIGNED

  const vector unsigned short v_1 = vec_splat_u16(1);
  const vector unsigned short v_2 = vec_splat_u16(2);
  const vector unsigned short v_4 = vec_splat_u16(4);

  const vector signed short v_diff01 = vec_sub(vb0, vb1);
  const vector unsigned short v_cmp01 =
    (const vector unsigned short) vec_cmplt(vec_abs(v_diff01), vqp);
  const vector signed short v_first = vec_sel(vb1, vb0, v_cmp01);
  const vector signed short v_diff89 = vec_sub(vb8, vb9);
  const vector unsigned short v_cmp89 =
    (const vector unsigned short) vec_cmplt(vec_abs(v_diff89), vqp);
  const vector signed short v_last = vec_sel(vb8, vb9, v_cmp89);

  const vector signed short temp01 = vec_mladd(v_first, (vector signed short)v_4, vb1);
  const vector signed short temp02 = vec_add(vb2, vb3);
  const vector signed short temp03 = vec_add(temp01, (vector signed short)v_4);
  const vector signed short v_sumsB0 = vec_add(temp02, temp03);

  const vector signed short temp11 = vec_sub(v_sumsB0, v_first);
  const vector signed short v_sumsB1 = vec_add(temp11, vb4);

  const vector signed short temp21 = vec_sub(v_sumsB1, v_first);
  const vector signed short v_sumsB2 = vec_add(temp21, vb5);

  const vector signed short temp31 = vec_sub(v_sumsB2, v_first);
  const vector signed short v_sumsB3 = vec_add(temp31, vb6);

  const vector signed short temp41 = vec_sub(v_sumsB3, v_first);
  const vector signed short v_sumsB4 = vec_add(temp41, vb7);

  const vector signed short temp51 = vec_sub(v_sumsB4, vb1);
  const vector signed short v_sumsB5 = vec_add(temp51, vb8);

  const vector signed short temp61 = vec_sub(v_sumsB5, vb2);
  const vector signed short v_sumsB6 = vec_add(temp61, v_last);

  const vector signed short temp71 = vec_sub(v_sumsB6, vb3);
  const vector signed short v_sumsB7 = vec_add(temp71, v_last);

  const vector signed short temp81 = vec_sub(v_sumsB7, vb4);
  const vector signed short v_sumsB8 = vec_add(temp81, v_last);

  const vector signed short temp91 = vec_sub(v_sumsB8, vb5);
  const vector signed short v_sumsB9 = vec_add(temp91, v_last);

#define COMPUTE_VR(i, j, k)                                             \
  const vector signed short temps1##i =                                 \
    vec_add(v_sumsB##i, v_sumsB##k);                                    \
  const vector signed short temps2##i =                                 \
    vec_mladd(vb##j, (vector signed short)v_2, temps1##i);              \
  const vector signed short  vr##j = vec_sra(temps2##i, v_4)

  COMPUTE_VR(0, 1, 2);
  COMPUTE_VR(1, 2, 3);
  COMPUTE_VR(2, 3, 4);
  COMPUTE_VR(3, 4, 5);
  COMPUTE_VR(4, 5, 6);
  COMPUTE_VR(5, 6, 7);
  COMPUTE_VR(6, 7, 8);
  COMPUTE_VR(7, 8, 9);

  const vector signed char neg1 = vec_splat_s8(-1);
  const vector unsigned char permHH = (const vector unsigned char)AVV(0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07,
                                                                      0x18, 0x19, 0x1A, 0x1B, 0x1C, 0x1D, 0x1E, 0x1F);

#define PACK_AND_STORE(i)                                       \
  const vector unsigned char perms##i =                         \
    vec_lvsr(i * stride, src2);                                 \
  const vector unsigned char vf##i =                            \
    vec_packsu(vr##i, (vector signed short)zero);               \
  const vector unsigned char vg##i =                            \
    vec_perm(vf##i, vbT##i, permHH);                            \
  const vector unsigned char mask##i =                          \
    vec_perm((vector unsigned char)zero, (vector unsigned char)neg1, perms##i); \
  const vector unsigned char vg2##i =                           \
    vec_perm(vg##i, vg##i, perms##i);                           \
  const vector unsigned char svA##i =                           \
    vec_sel(vbA##i, vg2##i, mask##i);                           \
  const vector unsigned char svB##i =                           \
    vec_sel(vg2##i, vbB##i, mask##i);                           \
  vec_st(svA##i, i * stride, src2);                             \
  vec_st(svB##i, i * stride + 16, src2)

#define PACK_AND_STORE_ALIGNED(i)                               \
  const vector unsigned char vf##i =                            \
    vec_packsu(vr##i, (vector signed short)zero);               \
  const vector unsigned char vg##i =                            \
    vec_perm(vf##i, vbT##i, permHH);                            \
  vec_st(vg##i, i * stride, src2)

  // special casing the aligned case is worthwhile, as all call from
  // the (transposed) horizontable deblocks will be aligned, in addition
  // to the naturraly aligned vertical deblocks.
  if (properStride && srcAlign) {
    PACK_AND_STORE_ALIGNED(1);
    PACK_AND_STORE_ALIGNED(2);
    PACK_AND_STORE_ALIGNED(3);
    PACK_AND_STORE_ALIGNED(4);
    PACK_AND_STORE_ALIGNED(5);
    PACK_AND_STORE_ALIGNED(6);
    PACK_AND_STORE_ALIGNED(7);
    PACK_AND_STORE_ALIGNED(8);
  } else {
    PACK_AND_STORE(1);
    PACK_AND_STORE(2);
    PACK_AND_STORE(3);
    PACK_AND_STORE(4);
    PACK_AND_STORE(5);
    PACK_AND_STORE(6);
    PACK_AND_STORE(7);
    PACK_AND_STORE(8);
  }
#undef PACK_AND_STORE
#undef PACK_AND_STORE_ALIGNED
}



static inline void doVertDefFilter_altivec(uint8_t src[], int stride, PPContext *c) {
  /*
    this code makes no assumption on src or stride.
    One could remove the recomputation of the perm
    vector by assuming (stride % 16) == 0, unfortunately
    this is not always true. Quite a lot of load/stores
    can be removed by assuming proper alignement of
    src & stride :-(
  */
  uint8_t *src2 = src;
  const vector signed int zero = vec_splat_s32(0);
  short __attribute__ ((aligned(16))) qp[8];
  qp[0] = 8*c->QP;
  vector signed short vqp = vec_ld(0, qp);
  vqp = vec_splat(vqp, 0);

#define LOAD_LINE(i)                                                    \
  const vector unsigned char perm##i =                                  \
    vec_lvsl(i * stride, src2);                                         \
  const vector unsigned char vbA##i =                                   \
    vec_ld(i * stride, src2);                                           \
  const vector unsigned char vbB##i =                                   \
    vec_ld(i * stride + 16, src2);                                      \
  const vector unsigned char vbT##i =                                   \
    vec_perm(vbA##i, vbB##i, perm##i);                                  \
  const vector signed short vb##i =                                     \
    (vector signed short)vec_mergeh((vector unsigned char)zero,         \
                                    (vector unsigned char)vbT##i)

  src2 += stride*3;

  LOAD_LINE(1);
  LOAD_LINE(2);
  LOAD_LINE(3);
  LOAD_LINE(4);
  LOAD_LINE(5);
  LOAD_LINE(6);
  LOAD_LINE(7);
  LOAD_LINE(8);
#undef LOAD_LINE

  const vector signed short v_1 = vec_splat_s16(1);
  const vector signed short v_2 = vec_splat_s16(2);
  const vector signed short v_5 = vec_splat_s16(5);
  const vector signed short v_32 = vec_sl(v_1,
                                          (vector unsigned short)v_5);
  /* middle energy */
  const vector signed short l3minusl6 = vec_sub(vb3, vb6);
  const vector signed short l5minusl4 = vec_sub(vb5, vb4);
  const vector signed short twotimes_l3minusl6 = vec_mladd(v_2, l3minusl6, (vector signed short)zero);
  const vector signed short mE = vec_mladd(v_5, l5minusl4, twotimes_l3minusl6);
  const vector signed short absmE = vec_abs(mE);
  /* left & right energy */
  const vector signed short l1minusl4 = vec_sub(vb1, vb4);
  const vector signed short l3minusl2 = vec_sub(vb3, vb2);
  const vector signed short l5minusl8 = vec_sub(vb5, vb8);
  const vector signed short l7minusl6 = vec_sub(vb7, vb6);
  const vector signed short twotimes_l1minusl4 = vec_mladd(v_2, l1minusl4, (vector signed short)zero);
  const vector signed short twotimes_l5minusl8 = vec_mladd(v_2, l5minusl8, (vector signed short)zero);
  const vector signed short lE = vec_mladd(v_5, l3minusl2, twotimes_l1minusl4);
  const vector signed short rE = vec_mladd(v_5, l7minusl6, twotimes_l5minusl8);
  /* d */
  const vector signed short ddiff = vec_sub(absmE,
                                            vec_min(vec_abs(lE),
                                                    vec_abs(rE)));
  const vector signed short ddiffclamp = vec_max(ddiff, (vector signed short)zero);
  const vector signed short dtimes64 = vec_mladd(v_5, ddiffclamp, v_32);
  const vector signed short d = vec_sra(dtimes64, vec_splat_u16(6));
  const vector signed short minusd = vec_sub((vector signed short)zero, d);
  const vector signed short finald = vec_sel(minusd,
                                             d,
                                             vec_cmpgt(vec_sub((vector signed short)zero, mE),
                                                       (vector signed short)zero));
  /* q */
  const vector signed short qtimes2 = vec_sub(vb4, vb5);
  /* for a shift right to behave like /2, we need to add one
     to all negative integer */
  const vector signed short rounddown = vec_sel((vector signed short)zero,
                                                v_1,
                                                vec_cmplt(qtimes2, (vector signed short)zero));
  const vector signed short q = vec_sra(vec_add(qtimes2, rounddown), vec_splat_u16(1));
  /* clamp */
  const vector signed short dclamp_P1 = vec_max((vector signed short)zero, finald);
  const vector signed short dclamp_P = vec_min(dclamp_P1, q);
  const vector signed short dclamp_N1 = vec_min((vector signed short)zero, finald);
  const vector signed short dclamp_N = vec_max(dclamp_N1, q);

  const vector signed short dclampedfinal = vec_sel(dclamp_N,
                                                    dclamp_P,
                                                    vec_cmpgt(q, (vector signed short)zero));
  const vector signed short dornotd = vec_sel((vector signed short)zero,
                                              dclampedfinal,
                                              vec_cmplt(absmE, vqp));
  /* add/substract to l4 and l5 */
  const vector signed short vb4minusd = vec_sub(vb4, dornotd);
  const vector signed short vb5plusd = vec_add(vb5, dornotd);
  /* finally, stores */
  const vector unsigned char st4 = vec_packsu(vb4minusd, (vector signed short)zero);
  const vector unsigned char st5 = vec_packsu(vb5plusd, (vector signed short)zero);

  const vector signed char neg1 = vec_splat_s8(-1);
  const vector unsigned char permHH = (const vector unsigned char)AVV(0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07,
                                                                      0x18, 0x19, 0x1A, 0x1B, 0x1C, 0x1D, 0x1E, 0x1F);

#define STORE(i)                                                \
  const vector unsigned char perms##i =                         \
    vec_lvsr(i * stride, src2);                                 \
  const vector unsigned char vg##i =                            \
    vec_perm(st##i, vbT##i, permHH);                            \
  const vector unsigned char mask##i =                          \
    vec_perm((vector unsigned char)zero, (vector unsigned char)neg1, perms##i); \
  const vector unsigned char vg2##i =                           \
    vec_perm(vg##i, vg##i, perms##i);                           \
  const vector unsigned char svA##i =                           \
    vec_sel(vbA##i, vg2##i, mask##i);                           \
  const vector unsigned char svB##i =                           \
    vec_sel(vg2##i, vbB##i, mask##i);                           \
  vec_st(svA##i, i * stride, src2);                             \
  vec_st(svB##i, i * stride + 16, src2)

  STORE(4);
  STORE(5);
}

static inline void dering_altivec(uint8_t src[], int stride, PPContext *c) {
  /*
    this code makes no assumption on src or stride.
    One could remove the recomputation of the perm
    vector by assuming (stride % 16) == 0, unfortunately
    this is not always true. Quite a lot of load/stores
    can be removed by assuming proper alignement of
    src & stride :-(
  */
  uint8_t *srcCopy = src;
  uint8_t __attribute__((aligned(16))) dt[16];
  const vector unsigned char vuint8_1 = vec_splat_u8(1);
  const vector signed int zero = vec_splat_s32(0);
  vector unsigned char v_dt;
  dt[0] = deringThreshold;
  v_dt = vec_splat(vec_ld(0, dt), 0);

#define LOAD_LINE(i)                                                    \
  const vector unsigned char perm##i =                                  \
    vec_lvsl(i * stride, srcCopy);                                      \
  vector unsigned char sA##i = vec_ld(i * stride, srcCopy);             \
  vector unsigned char sB##i = vec_ld(i * stride + 16, srcCopy);        \
  vector unsigned char src##i = vec_perm(sA##i, sB##i, perm##i)

  LOAD_LINE(0);
  LOAD_LINE(1);
  LOAD_LINE(2);
  LOAD_LINE(3);
  LOAD_LINE(4);
  LOAD_LINE(5);
  LOAD_LINE(6);
  LOAD_LINE(7);
  LOAD_LINE(8);
  LOAD_LINE(9);
#undef LOAD_LINE

  vector unsigned char v_avg;
  {
    const vector unsigned char trunc_perm = (vector unsigned char)
      AVV(0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08,
          0x11, 0x12, 0x13, 0x14, 0x15, 0x16, 0x17, 0x18);
    const vector unsigned char trunc_src12 = vec_perm(src1, src2, trunc_perm);
    const vector unsigned char trunc_src34 = vec_perm(src3, src4, trunc_perm);
    const vector unsigned char trunc_src56 = vec_perm(src5, src6, trunc_perm);
    const vector unsigned char trunc_src78 = vec_perm(src7, src8, trunc_perm);

#define EXTRACT(op) do {                                                \
      const vector unsigned char s##op##_1 = vec_##op(trunc_src12, trunc_src34); \
      const vector unsigned char s##op##_2 = vec_##op(trunc_src56, trunc_src78); \
      const vector unsigned char s##op##_6 = vec_##op(s##op##_1, s##op##_2); \
      const vector unsigned char s##op##_8h = vec_mergeh(s##op##_6, s##op##_6); \
      const vector unsigned char s##op##_8l = vec_mergel(s##op##_6, s##op##_6); \
      const vector unsigned char s##op##_9 = vec_##op(s##op##_8h, s##op##_8l); \
      const vector unsigned char s##op##_9h = vec_mergeh(s##op##_9, s##op##_9); \
      const vector unsigned char s##op##_9l = vec_mergel(s##op##_9, s##op##_9); \
      const vector unsigned char s##op##_10 = vec_##op(s##op##_9h, s##op##_9l); \
      const vector unsigned char s##op##_10h = vec_mergeh(s##op##_10, s##op##_10); \
      const vector unsigned char s##op##_10l = vec_mergel(s##op##_10, s##op##_10); \
      const vector unsigned char s##op##_11 = vec_##op(s##op##_10h, s##op##_10l); \
      const vector unsigned char s##op##_11h = vec_mergeh(s##op##_11, s##op##_11); \
      const vector unsigned char s##op##_11l = vec_mergel(s##op##_11, s##op##_11); \
      v_##op = vec_##op(s##op##_11h, s##op##_11l); } while (0)

    vector unsigned char v_min;
    vector unsigned char v_max;
    EXTRACT(min);
    EXTRACT(max);
#undef EXTRACT

    if (vec_all_lt(vec_sub(v_max, v_min), v_dt))
      return;

    v_avg = vec_avg(v_min, v_max);
  }

  signed int __attribute__((aligned(16))) S[8];
  {
    const vector unsigned short mask1 = (vector unsigned short)
      AVV(0x0001, 0x0002, 0x0004, 0x0008,
          0x0010, 0x0020, 0x0040, 0x0080);
    const vector unsigned short mask2 = (vector unsigned short)
      AVV(0x0100, 0x0200, 0x0000, 0x0000,
          0x0000, 0x0000, 0x0000, 0x0000);

    const vector unsigned int vuint32_16 = vec_sl(vec_splat_u32(1), vec_splat_u32(4));
    const vector unsigned int vuint32_1 = vec_splat_u32(1);

#define COMPARE(i)                                                      \
    vector signed int sum##i;                                           \
    do {                                                                \
      const vector unsigned char cmp##i =                               \
        (vector unsigned char)vec_cmpgt(src##i, v_avg);                 \
      const vector unsigned short cmpHi##i =                            \
        (vector unsigned short)vec_mergeh(cmp##i, cmp##i);              \
      const vector unsigned short cmpLi##i =                            \
        (vector unsigned short)vec_mergel(cmp##i, cmp##i);              \
      const vector signed short cmpHf##i =                              \
        (vector signed short)vec_and(cmpHi##i, mask1);                  \
      const vector signed short cmpLf##i =                              \
        (vector signed short)vec_and(cmpLi##i, mask2);                  \
      const vector signed int sump##i = vec_sum4s(cmpHf##i, zero);      \
      const vector signed int sumq##i = vec_sum4s(cmpLf##i, sump##i);   \
      sum##i  = vec_sums(sumq##i, zero); } while (0)

    COMPARE(0);
    COMPARE(1);
    COMPARE(2);
    COMPARE(3);
    COMPARE(4);
    COMPARE(5);
    COMPARE(6);
    COMPARE(7);
    COMPARE(8);
    COMPARE(9);
#undef COMPARE

    vector signed int sumA2;
    vector signed int sumB2;
    {
      const vector signed int sump02 = vec_mergel(sum0, sum2);
      const vector signed int sump13 = vec_mergel(sum1, sum3);
      const vector signed int sumA = vec_mergel(sump02, sump13);

      const vector signed int sump46 = vec_mergel(sum4, sum6);
      const vector signed int sump57 = vec_mergel(sum5, sum7);
      const vector signed int sumB = vec_mergel(sump46, sump57);

      const vector signed int sump8A = vec_mergel(sum8, zero);
      const vector signed int sump9B = vec_mergel(sum9, zero);
      const vector signed int sumC = vec_mergel(sump8A, sump9B);

      const vector signed int tA = vec_sl(vec_nor(zero, sumA), vuint32_16);
      const vector signed int tB = vec_sl(vec_nor(zero, sumB), vuint32_16);
      const vector signed int tC = vec_sl(vec_nor(zero, sumC), vuint32_16);
      const vector signed int t2A = vec_or(sumA, tA);
      const vector signed int t2B = vec_or(sumB, tB);
      const vector signed int t2C = vec_or(sumC, tC);
      const vector signed int t3A = vec_and(vec_sra(t2A, vuint32_1),
                                            vec_sl(t2A, vuint32_1));
      const vector signed int t3B = vec_and(vec_sra(t2B, vuint32_1),
                                            vec_sl(t2B, vuint32_1));
      const vector signed int t3C = vec_and(vec_sra(t2C, vuint32_1),
                                            vec_sl(t2C, vuint32_1));
      const vector signed int yA = vec_and(t2A, t3A);
      const vector signed int yB = vec_and(t2B, t3B);
      const vector signed int yC = vec_and(t2C, t3C);

      const vector unsigned char strangeperm1 = vec_lvsl(4, (unsigned char*)0);
      const vector unsigned char strangeperm2 = vec_lvsl(8, (unsigned char*)0);
      const vector signed int sumAd4 = vec_perm(yA, yB, strangeperm1);
      const vector signed int sumAd8 = vec_perm(yA, yB, strangeperm2);
      const vector signed int sumBd4 = vec_perm(yB, yC, strangeperm1);
      const vector signed int sumBd8 = vec_perm(yB, yC, strangeperm2);
      const vector signed int sumAp = vec_and(yA,
                                              vec_and(sumAd4,sumAd8));
      const vector signed int sumBp = vec_and(yB,
                                              vec_and(sumBd4,sumBd8));
      sumA2 = vec_or(sumAp,
                     vec_sra(sumAp,
                             vuint32_16));
      sumB2  = vec_or(sumBp,
                      vec_sra(sumBp,
                              vuint32_16));
    }
    vec_st(sumA2, 0, S);
    vec_st(sumB2, 16, S);
  }

  /* I'm not sure the following is actually faster
     than straight, unvectorized C code :-( */

  int __attribute__((aligned(16))) tQP2[4];
  tQP2[0]= c->QP/2 + 1;
  vector signed int vQP2 = vec_ld(0, tQP2);
  vQP2 = vec_splat(vQP2, 0);
  const vector unsigned char vuint8_2 = vec_splat_u8(2);
  const vector signed int vsint32_8 = vec_splat_s32(8);
  const vector unsigned int vuint32_4 = vec_splat_u32(4);

  const vector unsigned char permA1 = (vector unsigned char)
    AVV(0x00, 0x01, 0x02, 0x10, 0x11, 0x12, 0x1F, 0x1F,
        0x1F, 0x1F, 0x1F, 0x1F, 0x1F, 0x1F, 0x1F, 0x1F);
  const vector unsigned char permA2 = (vector unsigned char)
    AVV(0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x10, 0x11,
        0x12, 0x1F, 0x1F, 0x1F, 0x1F, 0x1F, 0x1F, 0x1F);
  const vector unsigned char permA1inc = (vector unsigned char)
    AVV(0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x00, 0x00,
        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00);
  const vector unsigned char permA2inc = (vector unsigned char)
    AVV(0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01, 0x01,
        0x01, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00);
  const vector unsigned char magic = (vector unsigned char)
    AVV(0x01, 0x02, 0x01, 0x02, 0x04, 0x02, 0x01, 0x02,
        0x01, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00);
  const vector unsigned char extractPerm = (vector unsigned char)
    AVV(0x10, 0x10, 0x10, 0x01, 0x10, 0x10, 0x10, 0x01,
        0x10, 0x10, 0x10, 0x01, 0x10, 0x10, 0x10, 0x01);
  const vector unsigned char extractPermInc = (vector unsigned char)
    AVV(0x00, 0x00, 0x00, 0x01, 0x00, 0x00, 0x00, 0x01,
        0x00, 0x00, 0x00, 0x01, 0x00, 0x00, 0x00, 0x01);
  const vector unsigned char identity = vec_lvsl(0,(unsigned char *)0);
  const vector unsigned char tenRight = (vector unsigned char)
    AVV(0x00, 0x10, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00);
  const vector unsigned char eightLeft = (vector unsigned char)
    AVV(0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x08);


#define F_INIT(i)                                       \
  vector unsigned char tenRightM##i = tenRight;         \
  vector unsigned char permA1M##i = permA1;             \
  vector unsigned char permA2M##i = permA2;             \
  vector unsigned char extractPermM##i = extractPerm

#define F2(i, j, k, l)                                                  \
  if (S[i] & (1 << (l+1))) {                                            \
    const vector unsigned char a_##j##_A##l =                           \
      vec_perm(src##i, src##j, permA1M##i);                             \
    const vector unsigned char a_##j##_B##l =                           \
      vec_perm(a_##j##_A##l, src##k, permA2M##i);                       \
    const vector signed int a_##j##_sump##l =                           \
      (vector signed int)vec_msum(a_##j##_B##l, magic,                  \
                                  (vector unsigned int)zero);           \
    vector signed int F_##j##_##l =                                     \
      vec_sr(vec_sums(a_##j##_sump##l, vsint32_8), vuint32_4);          \
    F_##j##_##l = vec_splat(F_##j##_##l, 3);                            \
    const vector signed int p_##j##_##l =                               \
      (vector signed int)vec_perm(src##j,                               \
                                  (vector unsigned char)zero,           \
                                  extractPermM##i);                     \
    const vector signed int sum_##j##_##l = vec_add( p_##j##_##l, vQP2);\
    const vector signed int diff_##j##_##l = vec_sub( p_##j##_##l, vQP2);\
    vector signed int newpm_##j##_##l;                                  \
    if (vec_all_lt(sum_##j##_##l, F_##j##_##l))                         \
      newpm_##j##_##l = sum_##j##_##l;                                  \
    else if (vec_all_gt(diff_##j##_##l, F_##j##_##l))                   \
      newpm_##j##_##l = diff_##j##_##l;                                 \
    else newpm_##j##_##l = F_##j##_##l;                                 \
    const vector unsigned char newpm2_##j##_##l =                       \
      vec_splat((vector unsigned char)newpm_##j##_##l, 15);             \
    const vector unsigned char mask##j##l = vec_add(identity,           \
                                                    tenRightM##i);      \
    src##j = vec_perm(src##j, newpm2_##j##_##l, mask##j##l);            \
  }                                                                     \
  permA1M##i = vec_add(permA1M##i, permA1inc);                          \
  permA2M##i = vec_add(permA2M##i, permA2inc);                          \
  tenRightM##i = vec_sro(tenRightM##i, eightLeft);                      \
  extractPermM##i = vec_add(extractPermM##i, extractPermInc)

#define ITER(i, j, k)                           \
  F_INIT(i);                                    \
  F2(i, j, k, 0);                               \
  F2(i, j, k, 1);                               \
  F2(i, j, k, 2);                               \
  F2(i, j, k, 3);                               \
  F2(i, j, k, 4);                               \
  F2(i, j, k, 5);                               \
  F2(i, j, k, 6);                               \
  F2(i, j, k, 7)

  ITER(0, 1, 2);
  ITER(1, 2, 3);
  ITER(2, 3, 4);
  ITER(3, 4, 5);
  ITER(4, 5, 6);
  ITER(5, 6, 7);
  ITER(6, 7, 8);
  ITER(7, 8, 9);

  const vector signed char neg1 = vec_splat_s8(-1);

#define STORE_LINE(i)                                   \
  const vector unsigned char permST##i =                \
    vec_lvsr(i * stride, srcCopy);                      \
  const vector unsigned char maskST##i =                \
    vec_perm((vector unsigned char)zero,                \
             (vector unsigned char)neg1, permST##i);    \
  src##i = vec_perm(src##i ,src##i, permST##i);         \
  sA##i= vec_sel(sA##i, src##i, maskST##i);             \
  sB##i= vec_sel(src##i, sB##i, maskST##i);             \
  vec_st(sA##i, i * stride, srcCopy);                   \
  vec_st(sB##i, i * stride + 16, srcCopy)

  STORE_LINE(1);
  STORE_LINE(2);
  STORE_LINE(3);
  STORE_LINE(4);
  STORE_LINE(5);
  STORE_LINE(6);
  STORE_LINE(7);
  STORE_LINE(8);

#undef STORE_LINE
#undef ITER
#undef F2
}

#define doHorizLowPass_altivec(a...) doHorizLowPass_C(a)
#define doHorizDefFilter_altivec(a...) doHorizDefFilter_C(a)
#define do_a_deblock_altivec(a...) do_a_deblock_C(a)

static inline void RENAME(tempNoiseReducer)(uint8_t *src, int stride,
                                    uint8_t *tempBlured, uint32_t *tempBluredPast, int *maxNoise)
{
  const vector signed int zero = vec_splat_s32(0);
  const vector signed short vsint16_1 = vec_splat_s16(1);
  vector signed int v_dp = zero;
  vector signed int v_sysdp = zero;
  int d, sysd, i;

  tempBluredPast[127]= maxNoise[0];
  tempBluredPast[128]= maxNoise[1];
  tempBluredPast[129]= maxNoise[2];

#define LOAD_LINE(src, i)                                               \
  register int j##src##i = i * stride;                                  \
  vector unsigned char perm##src##i = vec_lvsl(j##src##i, src);         \
  const vector unsigned char v_##src##A1##i = vec_ld(j##src##i, src);   \
  const vector unsigned char v_##src##A2##i = vec_ld(j##src##i + 16, src); \
  const vector unsigned char v_##src##A##i =                            \
    vec_perm(v_##src##A1##i, v_##src##A2##i, perm##src##i);             \
  vector signed short v_##src##Ass##i =                                 \
    (vector signed short)vec_mergeh((vector signed char)zero,           \
                                    (vector signed char)v_##src##A##i)

  LOAD_LINE(src, 0);
  LOAD_LINE(src, 1);
  LOAD_LINE(src, 2);
  LOAD_LINE(src, 3);
  LOAD_LINE(src, 4);
  LOAD_LINE(src, 5);
  LOAD_LINE(src, 6);
  LOAD_LINE(src, 7);

  LOAD_LINE(tempBlured, 0);
  LOAD_LINE(tempBlured, 1);
  LOAD_LINE(tempBlured, 2);
  LOAD_LINE(tempBlured, 3);
  LOAD_LINE(tempBlured, 4);
  LOAD_LINE(tempBlured, 5);
  LOAD_LINE(tempBlured, 6);
  LOAD_LINE(tempBlured, 7);
#undef LOAD_LINE

#define ACCUMULATE_DIFFS(i)                                     \
  vector signed short v_d##i = vec_sub(v_tempBluredAss##i,      \
                                       v_srcAss##i);            \
  v_dp = vec_msums(v_d##i, v_d##i, v_dp);                       \
  v_sysdp = vec_msums(v_d##i, vsint16_1, v_sysdp)

  ACCUMULATE_DIFFS(0);
  ACCUMULATE_DIFFS(1);
  ACCUMULATE_DIFFS(2);
  ACCUMULATE_DIFFS(3);
  ACCUMULATE_DIFFS(4);
  ACCUMULATE_DIFFS(5);
  ACCUMULATE_DIFFS(6);
  ACCUMULATE_DIFFS(7);
#undef ACCUMULATE_DIFFS

  v_dp = vec_sums(v_dp, zero);
  v_sysdp = vec_sums(v_sysdp, zero);

  v_dp = vec_splat(v_dp, 3);
  v_sysdp = vec_splat(v_sysdp, 3);

  vec_ste(v_dp, 0, &d);
  vec_ste(v_sysdp, 0, &sysd);

  i = d;
  d = (4*d
       +(*(tempBluredPast-256))
       +(*(tempBluredPast-1))+ (*(tempBluredPast+1))
       +(*(tempBluredPast+256))
       +4)>>3;

  *tempBluredPast=i;

  if (d > maxNoise[1]) {
    if (d < maxNoise[2]) {
#define OP(i) v_tempBluredAss##i = vec_avg(v_tempBluredAss##i, v_srcAss##i);

      OP(0);
      OP(1);
      OP(2);
      OP(3);
      OP(4);
      OP(5);
      OP(6);
      OP(7);
#undef OP
    } else {
#define OP(i) v_tempBluredAss##i = v_srcAss##i;

      OP(0);
      OP(1);
      OP(2);
      OP(3);
      OP(4);
      OP(5);
      OP(6);
      OP(7);
#undef OP
    }
  } else {
    if (d < maxNoise[0]) {
      const vector signed short vsint16_7 = vec_splat_s16(7);
      const vector signed short vsint16_4 = vec_splat_s16(4);
      const vector unsigned short vuint16_3 = vec_splat_u16(3);

#define OP(i)                                                   \
      const vector signed short v_temp##i =                     \
        vec_mladd(v_tempBluredAss##i,                           \
                  vsint16_7, v_srcAss##i);                      \
      const vector signed short v_temp2##i =                    \
        vec_add(v_temp##i, vsint16_4);                          \
      v_tempBluredAss##i = vec_sr(v_temp2##i, vuint16_3)

      OP(0);
      OP(1);
      OP(2);
      OP(3);
      OP(4);
      OP(5);
      OP(6);
      OP(7);
#undef OP
    } else {
      const vector signed short vsint16_3 = vec_splat_s16(3);
      const vector signed short vsint16_2 = vec_splat_s16(2);

#define OP(i)                                                   \
      const vector signed short v_temp##i =                     \
        vec_mladd(v_tempBluredAss##i,                           \
                  vsint16_3, v_srcAss##i);                      \
      const vector signed short v_temp2##i =                    \
        vec_add(v_temp##i, vsint16_2);                          \
      v_tempBluredAss##i = vec_sr(v_temp2##i, (vector unsigned short)vsint16_2)

      OP(0);
      OP(1);
      OP(2);
      OP(3);
      OP(4);
      OP(5);
      OP(6);
      OP(7);
#undef OP
    }
  }

  const vector signed char neg1 = vec_splat_s8(-1);
  const vector unsigned char permHH = (const vector unsigned char)AVV(0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07,
                                                                      0x18, 0x19, 0x1A, 0x1B, 0x1C, 0x1D, 0x1E, 0x1F);

#define PACK_AND_STORE(src, i)                                  \
  const vector unsigned char perms##src##i =                    \
    vec_lvsr(i * stride, src);                                  \
  const vector unsigned char vf##src##i =                       \
    vec_packsu(v_tempBluredAss##i, (vector signed short)zero);  \
  const vector unsigned char vg##src##i =                       \
    vec_perm(vf##src##i, v_##src##A##i, permHH);                \
  const vector unsigned char mask##src##i =                     \
    vec_perm((vector unsigned char)zero, (vector unsigned char)neg1, perms##src##i); \
  const vector unsigned char vg2##src##i =                      \
    vec_perm(vg##src##i, vg##src##i, perms##src##i);            \
  const vector unsigned char svA##src##i =                      \
    vec_sel(v_##src##A1##i, vg2##src##i, mask##src##i);         \
  const vector unsigned char svB##src##i =                      \
    vec_sel(vg2##src##i, v_##src##A2##i, mask##src##i);         \
  vec_st(svA##src##i, i * stride, src);                         \
  vec_st(svB##src##i, i * stride + 16, src)

  PACK_AND_STORE(src, 0);
  PACK_AND_STORE(src, 1);
  PACK_AND_STORE(src, 2);
  PACK_AND_STORE(src, 3);
  PACK_AND_STORE(src, 4);
  PACK_AND_STORE(src, 5);
  PACK_AND_STORE(src, 6);
  PACK_AND_STORE(src, 7);
  PACK_AND_STORE(tempBlured, 0);
  PACK_AND_STORE(tempBlured, 1);
  PACK_AND_STORE(tempBlured, 2);
  PACK_AND_STORE(tempBlured, 3);
  PACK_AND_STORE(tempBlured, 4);
  PACK_AND_STORE(tempBlured, 5);
  PACK_AND_STORE(tempBlured, 6);
  PACK_AND_STORE(tempBlured, 7);
#undef PACK_AND_STORE
}

static inline void transpose_16x8_char_toPackedAlign_altivec(unsigned char* dst, unsigned char* src, int stride) {
  const vector unsigned char zero = vec_splat_u8(0);

#define LOAD_DOUBLE_LINE(i, j)                                          \
  vector unsigned char perm1##i = vec_lvsl(i * stride, src);            \
  vector unsigned char perm2##i = vec_lvsl(j * stride, src);            \
  vector unsigned char srcA##i = vec_ld(i * stride, src);               \
  vector unsigned char srcB##i = vec_ld(i * stride + 16, src);          \
  vector unsigned char srcC##i = vec_ld(j * stride, src);               \
  vector unsigned char srcD##i = vec_ld(j * stride+ 16, src);           \
  vector unsigned char src##i = vec_perm(srcA##i, srcB##i, perm1##i);   \
  vector unsigned char src##j = vec_perm(srcC##i, srcD##i, perm2##i)

  LOAD_DOUBLE_LINE(0, 1);
  LOAD_DOUBLE_LINE(2, 3);
  LOAD_DOUBLE_LINE(4, 5);
  LOAD_DOUBLE_LINE(6, 7);
#undef LOAD_DOUBLE_LINE

  vector unsigned char tempA = vec_mergeh(src0, zero);
  vector unsigned char tempB = vec_mergel(src0, zero);
  vector unsigned char tempC = vec_mergeh(src1, zero);
  vector unsigned char tempD = vec_mergel(src1, zero);
  vector unsigned char tempE = vec_mergeh(src2, zero);
  vector unsigned char tempF = vec_mergel(src2, zero);
  vector unsigned char tempG = vec_mergeh(src3, zero);
  vector unsigned char tempH = vec_mergel(src3, zero);
  vector unsigned char tempI = vec_mergeh(src4, zero);
  vector unsigned char tempJ = vec_mergel(src4, zero);
  vector unsigned char tempK = vec_mergeh(src5, zero);
  vector unsigned char tempL = vec_mergel(src5, zero);
  vector unsigned char tempM = vec_mergeh(src6, zero);
  vector unsigned char tempN = vec_mergel(src6, zero);
  vector unsigned char tempO = vec_mergeh(src7, zero);
  vector unsigned char tempP = vec_mergel(src7, zero);

  vector unsigned char temp0 = vec_mergeh(tempA, tempI);
  vector unsigned char temp1 = vec_mergel(tempA, tempI);
  vector unsigned char temp2 = vec_mergeh(tempB, tempJ);
  vector unsigned char temp3 = vec_mergel(tempB, tempJ);
  vector unsigned char temp4 = vec_mergeh(tempC, tempK);
  vector unsigned char temp5 = vec_mergel(tempC, tempK);
  vector unsigned char temp6 = vec_mergeh(tempD, tempL);
  vector unsigned char temp7 = vec_mergel(tempD, tempL);
  vector unsigned char temp8 = vec_mergeh(tempE, tempM);
  vector unsigned char temp9 = vec_mergel(tempE, tempM);
  vector unsigned char temp10 = vec_mergeh(tempF, tempN);
  vector unsigned char temp11 = vec_mergel(tempF, tempN);
  vector unsigned char temp12 = vec_mergeh(tempG, tempO);
  vector unsigned char temp13 = vec_mergel(tempG, tempO);
  vector unsigned char temp14 = vec_mergeh(tempH, tempP);
  vector unsigned char temp15 = vec_mergel(tempH, tempP);

  tempA = vec_mergeh(temp0, temp8);
  tempB = vec_mergel(temp0, temp8);
  tempC = vec_mergeh(temp1, temp9);
  tempD = vec_mergel(temp1, temp9);
  tempE = vec_mergeh(temp2, temp10);
  tempF = vec_mergel(temp2, temp10);
  tempG = vec_mergeh(temp3, temp11);
  tempH = vec_mergel(temp3, temp11);
  tempI = vec_mergeh(temp4, temp12);
  tempJ = vec_mergel(temp4, temp12);
  tempK = vec_mergeh(temp5, temp13);
  tempL = vec_mergel(temp5, temp13);
  tempM = vec_mergeh(temp6, temp14);
  tempN = vec_mergel(temp6, temp14);
  tempO = vec_mergeh(temp7, temp15);
  tempP = vec_mergel(temp7, temp15);

  temp0 = vec_mergeh(tempA, tempI);
  temp1 = vec_mergel(tempA, tempI);
  temp2 = vec_mergeh(tempB, tempJ);
  temp3 = vec_mergel(tempB, tempJ);
  temp4 = vec_mergeh(tempC, tempK);
  temp5 = vec_mergel(tempC, tempK);
  temp6 = vec_mergeh(tempD, tempL);
  temp7 = vec_mergel(tempD, tempL);
  temp8 = vec_mergeh(tempE, tempM);
  temp9 = vec_mergel(tempE, tempM);
  temp10 = vec_mergeh(tempF, tempN);
  temp11 = vec_mergel(tempF, tempN);
  temp12 = vec_mergeh(tempG, tempO);
  temp13 = vec_mergel(tempG, tempO);
  temp14 = vec_mergeh(tempH, tempP);
  temp15 = vec_mergel(tempH, tempP);

  vec_st(temp0, 0, dst);
  vec_st(temp1, 16, dst);
  vec_st(temp2, 32, dst);
  vec_st(temp3, 48, dst);
  vec_st(temp4, 64, dst);
  vec_st(temp5, 80, dst);
  vec_st(temp6, 96, dst);
  vec_st(temp7, 112, dst);
  vec_st(temp8, 128, dst);
  vec_st(temp9, 144, dst);
  vec_st(temp10, 160, dst);
  vec_st(temp11, 176, dst);
  vec_st(temp12, 192, dst);
  vec_st(temp13, 208, dst);
  vec_st(temp14, 224, dst);
  vec_st(temp15, 240, dst);
}

static inline void transpose_8x16_char_fromPackedAlign_altivec(unsigned char* dst, unsigned char* src, int stride) {
  const vector unsigned char zero = vec_splat_u8(0);
  const vector unsigned char magic_perm = (const vector unsigned char)
    AVV(0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07,
        0x18, 0x19, 0x1A, 0x1B, 0x1C, 0x1D, 0x1E, 0x1F);

#define LOAD_DOUBLE_LINE(i, j)                                  \
  vector unsigned char src##i = vec_ld(i * 16, src);            \
  vector unsigned char src##j = vec_ld(j * 16, src)

  LOAD_DOUBLE_LINE(0, 1);
  LOAD_DOUBLE_LINE(2, 3);
  LOAD_DOUBLE_LINE(4, 5);
  LOAD_DOUBLE_LINE(6, 7);
  LOAD_DOUBLE_LINE(8, 9);
  LOAD_DOUBLE_LINE(10, 11);
  LOAD_DOUBLE_LINE(12, 13);
  LOAD_DOUBLE_LINE(14, 15);
#undef LOAD_DOUBLE_LINE

  vector unsigned char tempA = vec_mergeh(src0, src8);
  vector unsigned char tempB;
  vector unsigned char tempC = vec_mergeh(src1, src9);
  vector unsigned char tempD;
  vector unsigned char tempE = vec_mergeh(src2, src10);
  vector unsigned char tempG = vec_mergeh(src3, src11);
  vector unsigned char tempI = vec_mergeh(src4, src12);
  vector unsigned char tempJ;
  vector unsigned char tempK = vec_mergeh(src5, src13);
  vector unsigned char tempL;
  vector unsigned char tempM = vec_mergeh(src6, src14);
  vector unsigned char tempO = vec_mergeh(src7, src15);

  vector unsigned char temp0 = vec_mergeh(tempA, tempI);
  vector unsigned char temp1 = vec_mergel(tempA, tempI);
  vector unsigned char temp2;
  vector unsigned char temp3;
  vector unsigned char temp4 = vec_mergeh(tempC, tempK);
  vector unsigned char temp5 = vec_mergel(tempC, tempK);
  vector unsigned char temp6;
  vector unsigned char temp7;
  vector unsigned char temp8 = vec_mergeh(tempE, tempM);
  vector unsigned char temp9 = vec_mergel(tempE, tempM);
  vector unsigned char temp12 = vec_mergeh(tempG, tempO);
  vector unsigned char temp13 = vec_mergel(tempG, tempO);

  tempA = vec_mergeh(temp0, temp8);
  tempB = vec_mergel(temp0, temp8);
  tempC = vec_mergeh(temp1, temp9);
  tempD = vec_mergel(temp1, temp9);
  tempI = vec_mergeh(temp4, temp12);
  tempJ = vec_mergel(temp4, temp12);
  tempK = vec_mergeh(temp5, temp13);
  tempL = vec_mergel(temp5, temp13);

  temp0 = vec_mergeh(tempA, tempI);
  temp1 = vec_mergel(tempA, tempI);
  temp2 = vec_mergeh(tempB, tempJ);
  temp3 = vec_mergel(tempB, tempJ);
  temp4 = vec_mergeh(tempC, tempK);
  temp5 = vec_mergel(tempC, tempK);
  temp6 = vec_mergeh(tempD, tempL);
  temp7 = vec_mergel(tempD, tempL);


  const vector signed char neg1 = vec_splat_s8(-1);
#define STORE_DOUBLE_LINE(i, j)                                         \
  vector unsigned char dstA##i = vec_ld(i * stride, dst);               \
  vector unsigned char dstB##i = vec_ld(i * stride + 16, dst);          \
  vector unsigned char dstA##j = vec_ld(j * stride, dst);               \
  vector unsigned char dstB##j = vec_ld(j * stride+ 16, dst);           \
  vector unsigned char align##i = vec_lvsr(i * stride, dst);            \
  vector unsigned char align##j = vec_lvsr(j * stride, dst);            \
  vector unsigned char mask##i = vec_perm(zero, (vector unsigned char)neg1, align##i); \
  vector unsigned char mask##j = vec_perm(zero, (vector unsigned char)neg1, align##j); \
  vector unsigned char dstR##i = vec_perm(temp##i, temp##i, align##i);  \
  vector unsigned char dstR##j = vec_perm(temp##j, temp##j, align##j);  \
  vector unsigned char dstAF##i = vec_sel(dstA##i, dstR##i, mask##i);   \
  vector unsigned char dstBF##i = vec_sel(dstR##i, dstB##i, mask##i);   \
  vector unsigned char dstAF##j = vec_sel(dstA##j, dstR##j, mask##j);   \
  vector unsigned char dstBF##j = vec_sel(dstR##j, dstB##j, mask##j);   \
  vec_st(dstAF##i, i * stride, dst);                                    \
  vec_st(dstBF##i, i * stride + 16, dst);                               \
  vec_st(dstAF##j, j * stride, dst);                                    \
  vec_st(dstBF##j, j * stride + 16, dst)

  STORE_DOUBLE_LINE(0,1);
  STORE_DOUBLE_LINE(2,3);
  STORE_DOUBLE_LINE(4,5);
  STORE_DOUBLE_LINE(6,7);
}