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jdmrgext-altivec.c (12300B)


      1 /*
      2 * AltiVec optimizations for libjpeg-turbo
      3 *
      4 * Copyright (C) 2015, D. R. Commander.  All Rights Reserved.
      5 *
      6 * This software is provided 'as-is', without any express or implied
      7 * warranty.  In no event will the authors be held liable for any damages
      8 * arising from the use of this software.
      9 *
     10 * Permission is granted to anyone to use this software for any purpose,
     11 * including commercial applications, and to alter it and redistribute it
     12 * freely, subject to the following restrictions:
     13 *
     14 * 1. The origin of this software must not be misrepresented; you must not
     15 *    claim that you wrote the original software. If you use this software
     16 *    in a product, an acknowledgment in the product documentation would be
     17 *    appreciated but is not required.
     18 * 2. Altered source versions must be plainly marked as such, and must not be
     19 *    misrepresented as being the original software.
     20 * 3. This notice may not be removed or altered from any source distribution.
     21 */
     22 
     23 /* This file is included by jdmerge-altivec.c */
     24 
     25 
     26 void jsimd_h2v1_merged_upsample_altivec(JDIMENSION output_width,
     27                                        JSAMPIMAGE input_buf,
     28                                        JDIMENSION in_row_group_ctr,
     29                                        JSAMPARRAY output_buf)
     30 {
     31  JSAMPROW outptr, inptr0, inptr1, inptr2;
     32  int pitch = output_width * RGB_PIXELSIZE, num_cols, yloop;
     33 #if __BIG_ENDIAN__
     34  int offset;
     35 #endif
     36  unsigned char __attribute__((aligned(16))) tmpbuf[RGB_PIXELSIZE * 16];
     37 
     38  __vector unsigned char rgb0, rgb1, rgb2, rgbx0, rgbx1, rgbx2, rgbx3,
     39    y, cb, cr;
     40 #if __BIG_ENDIAN__
     41  __vector unsigned char edgel, edgeh, edges, out0, out1, out2, out3;
     42 #if RGB_PIXELSIZE == 4
     43  __vector unsigned char out4;
     44 #endif
     45 #endif
     46 #if RGB_PIXELSIZE == 4
     47  __vector unsigned char rgb3;
     48 #endif
     49  __vector short rg0, rg1, rg2, rg3, bx0, bx1, bx2, bx3, ye, yo, cbl, cbh,
     50    crl, crh, r_yl, r_yh, g_yl, g_yh, b_yl, b_yh, g_y0w, g_y1w, g_y2w, g_y3w,
     51    rl, rh, gl, gh, bl, bh, re, ro, ge, go, be, bo;
     52  __vector int g_y0, g_y1, g_y2, g_y3;
     53 
     54  /* Constants
     55   * NOTE: The >> 1 is to compensate for the fact that vec_madds() returns 17
     56   * high-order bits, not 16.
     57   */
     58  __vector short pw_f0402 = { __8X(F_0_402 >> 1) },
     59    pw_mf0228 = { __8X(-F_0_228 >> 1) },
     60    pw_mf0344_f0285 = { __4X2(-F_0_344, F_0_285) },
     61    pw_one = { __8X(1) }, pw_255 = { __8X(255) },
     62    pw_cj = { __8X(CENTERJSAMPLE) };
     63  __vector int pd_onehalf = { __4X(ONE_HALF) };
     64  __vector unsigned char pb_zero = { __16X(0) },
     65 #if __BIG_ENDIAN__
     66    shift_pack_index =
     67      {  0,  1,  4,  5,  8,  9, 12, 13, 16, 17, 20, 21, 24, 25, 28, 29 },
     68    even_index =
     69      {  0, 16,  0, 18,  0, 20,  0, 22,  0, 24,  0, 26,  0, 28,  0, 30 },
     70    odd_index =
     71      {  0, 17,  0, 19,  0, 21,  0, 23,  0, 25,  0, 27,  0, 29,  0, 31 };
     72 #else
     73    shift_pack_index =
     74      {  2,  3,  6,  7, 10, 11, 14, 15, 18, 19, 22, 23, 26, 27, 30, 31 },
     75    even_index =
     76      { 16,  0, 18,  0, 20,  0, 22,  0, 24,  0, 26,  0, 28,  0, 30,  0 },
     77    odd_index =
     78      { 17,  0, 19,  0, 21,  0, 23,  0, 25,  0, 27,  0, 29,  0, 31,  0 };
     79 #endif
     80 
     81  inptr0 = input_buf[0][in_row_group_ctr];
     82  inptr1 = input_buf[1][in_row_group_ctr];
     83  inptr2 = input_buf[2][in_row_group_ctr];
     84  outptr = output_buf[0];
     85 
     86  for (num_cols = pitch; num_cols > 0; inptr1 += 16, inptr2 += 16) {
     87 
     88    cb = vec_ld(0, inptr1);
     89    /* NOTE: We have to use vec_merge*() here because vec_unpack*() doesn't
     90     * support unsigned vectors.
     91     */
     92    cbl = (__vector signed short)VEC_UNPACKHU(cb);
     93    cbh = (__vector signed short)VEC_UNPACKLU(cb);
     94    cbl = vec_sub(cbl, pw_cj);
     95    cbh = vec_sub(cbh, pw_cj);
     96 
     97    cr = vec_ld(0, inptr2);
     98    crl = (__vector signed short)VEC_UNPACKHU(cr);
     99    crh = (__vector signed short)VEC_UNPACKLU(cr);
    100    crl = vec_sub(crl, pw_cj);
    101    crh = vec_sub(crh, pw_cj);
    102 
    103    /* (Original)
    104     * R = Y                + 1.40200 * Cr
    105     * G = Y - 0.34414 * Cb - 0.71414 * Cr
    106     * B = Y + 1.77200 * Cb
    107     *
    108     * (This implementation)
    109     * R = Y                + 0.40200 * Cr + Cr
    110     * G = Y - 0.34414 * Cb + 0.28586 * Cr - Cr
    111     * B = Y - 0.22800 * Cb + Cb + Cb
    112     */
    113    b_yl = vec_add(cbl, cbl);
    114    b_yh = vec_add(cbh, cbh);
    115    b_yl = vec_madds(b_yl, pw_mf0228, pw_one);
    116    b_yh = vec_madds(b_yh, pw_mf0228, pw_one);
    117    b_yl = vec_sra(b_yl, (__vector unsigned short)pw_one);
    118    b_yh = vec_sra(b_yh, (__vector unsigned short)pw_one);
    119    b_yl = vec_add(b_yl, cbl);
    120    b_yh = vec_add(b_yh, cbh);
    121    b_yl = vec_add(b_yl, cbl);
    122    b_yh = vec_add(b_yh, cbh);
    123 
    124    r_yl = vec_add(crl, crl);
    125    r_yh = vec_add(crh, crh);
    126    r_yl = vec_madds(r_yl, pw_f0402, pw_one);
    127    r_yh = vec_madds(r_yh, pw_f0402, pw_one);
    128    r_yl = vec_sra(r_yl, (__vector unsigned short)pw_one);
    129    r_yh = vec_sra(r_yh, (__vector unsigned short)pw_one);
    130    r_yl = vec_add(r_yl, crl);
    131    r_yh = vec_add(r_yh, crh);
    132 
    133    g_y0w = vec_mergeh(cbl, crl);
    134    g_y1w = vec_mergel(cbl, crl);
    135    g_y0 = vec_msums(g_y0w, pw_mf0344_f0285, pd_onehalf);
    136    g_y1 = vec_msums(g_y1w, pw_mf0344_f0285, pd_onehalf);
    137    g_y2w = vec_mergeh(cbh, crh);
    138    g_y3w = vec_mergel(cbh, crh);
    139    g_y2 = vec_msums(g_y2w, pw_mf0344_f0285, pd_onehalf);
    140    g_y3 = vec_msums(g_y3w, pw_mf0344_f0285, pd_onehalf);
    141    /* Clever way to avoid 4 shifts + 2 packs.  This packs the high word from
    142     * each dword into a new 16-bit vector, which is the equivalent of
    143     * descaling the 32-bit results (right-shifting by 16 bits) and then
    144     * packing them.
    145     */
    146    g_yl = vec_perm((__vector short)g_y0, (__vector short)g_y1,
    147                    shift_pack_index);
    148    g_yh = vec_perm((__vector short)g_y2, (__vector short)g_y3,
    149                    shift_pack_index);
    150    g_yl = vec_sub(g_yl, crl);
    151    g_yh = vec_sub(g_yh, crh);
    152 
    153    for (yloop = 0; yloop < 2 && num_cols > 0; yloop++,
    154         num_cols -= RGB_PIXELSIZE * 16,
    155         outptr += RGB_PIXELSIZE * 16, inptr0 += 16) {
    156 
    157      y = vec_ld(0, inptr0);
    158      ye = (__vector signed short)vec_perm(pb_zero, y, even_index);
    159      yo = (__vector signed short)vec_perm(pb_zero, y, odd_index);
    160 
    161      if (yloop == 0) {
    162        be = vec_add(b_yl, ye);
    163        bo = vec_add(b_yl, yo);
    164        re = vec_add(r_yl, ye);
    165        ro = vec_add(r_yl, yo);
    166        ge = vec_add(g_yl, ye);
    167        go = vec_add(g_yl, yo);
    168      } else {
    169        be = vec_add(b_yh, ye);
    170        bo = vec_add(b_yh, yo);
    171        re = vec_add(r_yh, ye);
    172        ro = vec_add(r_yh, yo);
    173        ge = vec_add(g_yh, ye);
    174        go = vec_add(g_yh, yo);
    175      }
    176 
    177      rl = vec_mergeh(re, ro);
    178      rh = vec_mergel(re, ro);
    179      gl = vec_mergeh(ge, go);
    180      gh = vec_mergel(ge, go);
    181      bl = vec_mergeh(be, bo);
    182      bh = vec_mergel(be, bo);
    183 
    184      rg0 = vec_mergeh(rl, gl);
    185      bx0 = vec_mergeh(bl, pw_255);
    186      rg1 = vec_mergel(rl, gl);
    187      bx1 = vec_mergel(bl, pw_255);
    188      rg2 = vec_mergeh(rh, gh);
    189      bx2 = vec_mergeh(bh, pw_255);
    190      rg3 = vec_mergel(rh, gh);
    191      bx3 = vec_mergel(bh, pw_255);
    192 
    193      rgbx0 = vec_packsu(rg0, bx0);
    194      rgbx1 = vec_packsu(rg1, bx1);
    195      rgbx2 = vec_packsu(rg2, bx2);
    196      rgbx3 = vec_packsu(rg3, bx3);
    197 
    198 #if RGB_PIXELSIZE == 3
    199      /* rgbx0 = R0 G0 R1 G1 R2 G2 R3 G3 B0 X0 B1 X1 B2 X2 B3 X3
    200       * rgbx1 = R4 G4 R5 G5 R6 G6 R7 G7 B4 X4 B5 X5 B6 X6 B7 X7
    201       * rgbx2 = R8 G8 R9 G9 Ra Ga Rb Gb B8 X8 B9 X9 Ba Xa Bb Xb
    202       * rgbx3 = Rc Gc Rd Gd Re Ge Rf Gf Bc Xc Bd Xd Be Xe Bf Xf
    203       *
    204       * rgb0 = R0 G0 B0 R1 G1 B1 R2 G2 B2 R3 G3 B3 R4 G4 B4 R5
    205       * rgb1 = G5 B5 R6 G6 B6 R7 G7 B7 R8 G8 B8 R9 G9 B9 Ra Ga
    206       * rgb2 = Ba Rb Gb Bb Rc Gc Bc Rd Gd Bd Re Ge Be Rf Gf Bf
    207       */
    208      rgb0 = vec_perm(rgbx0, rgbx1, (__vector unsigned char)RGB_INDEX0);
    209      rgb1 = vec_perm(rgbx1, rgbx2, (__vector unsigned char)RGB_INDEX1);
    210      rgb2 = vec_perm(rgbx2, rgbx3, (__vector unsigned char)RGB_INDEX2);
    211 #else
    212      /* rgbx0 = R0 G0 R1 G1 R2 G2 R3 G3 B0 X0 B1 X1 B2 X2 B3 X3
    213       * rgbx1 = R4 G4 R5 G5 R6 G6 R7 G7 B4 X4 B5 X5 B6 X6 B7 X7
    214       * rgbx2 = R8 G8 R9 G9 Ra Ga Rb Gb B8 X8 B9 X9 Ba Xa Bb Xb
    215       * rgbx3 = Rc Gc Rd Gd Re Ge Rf Gf Bc Xc Bd Xd Be Xe Bf Xf
    216       *
    217       * rgb0 = R0 G0 B0 X0 R1 G1 B1 X1 R2 G2 B2 X2 R3 G3 B3 X3
    218       * rgb1 = R4 G4 B4 X4 R5 G5 B5 X5 R6 G6 B6 X6 R7 G7 B7 X7
    219       * rgb2 = R8 G8 B8 X8 R9 G9 B9 X9 Ra Ga Ba Xa Rb Gb Bb Xb
    220       * rgb3 = Rc Gc Bc Xc Rd Gd Bd Xd Re Ge Be Xe Rf Gf Bf Xf
    221       */
    222      rgb0 = vec_perm(rgbx0, rgbx0, (__vector unsigned char)RGB_INDEX);
    223      rgb1 = vec_perm(rgbx1, rgbx1, (__vector unsigned char)RGB_INDEX);
    224      rgb2 = vec_perm(rgbx2, rgbx2, (__vector unsigned char)RGB_INDEX);
    225      rgb3 = vec_perm(rgbx3, rgbx3, (__vector unsigned char)RGB_INDEX);
    226 #endif
    227 
    228 #if __BIG_ENDIAN__
    229      offset = (size_t)outptr & 15;
    230      if (offset) {
    231        __vector unsigned char unaligned_shift_index;
    232        int bytes = num_cols + offset;
    233 
    234        if (bytes < (RGB_PIXELSIZE + 1) * 16 && (bytes & 15)) {
    235          /* Slow path to prevent buffer overwrite.  Since there is no way to
    236           * write a partial AltiVec register, overwrite would occur on the
    237           * last chunk of the last image row if the right edge is not on a
    238           * 16-byte boundary.  It could also occur on other rows if the bytes
    239           * per row is low enough.  Since we can't determine whether we're on
    240           * the last image row, we have to assume every row is the last.
    241           */
    242          vec_st(rgb0, 0, tmpbuf);
    243          vec_st(rgb1, 16, tmpbuf);
    244          vec_st(rgb2, 32, tmpbuf);
    245 #if RGB_PIXELSIZE == 4
    246          vec_st(rgb3, 48, tmpbuf);
    247 #endif
    248          memcpy(outptr, tmpbuf, min(num_cols, RGB_PIXELSIZE * 16));
    249        } else {
    250          /* Fast path */
    251          unaligned_shift_index = vec_lvsl(0, outptr);
    252          edgel = vec_ld(0, outptr);
    253          edgeh = vec_ld(min(num_cols - 1, RGB_PIXELSIZE * 16), outptr);
    254          edges = vec_perm(edgeh, edgel, unaligned_shift_index);
    255          unaligned_shift_index = vec_lvsr(0, outptr);
    256          out0 = vec_perm(edges, rgb0, unaligned_shift_index);
    257          out1 = vec_perm(rgb0, rgb1, unaligned_shift_index);
    258          out2 = vec_perm(rgb1, rgb2, unaligned_shift_index);
    259 #if RGB_PIXELSIZE == 4
    260          out3 = vec_perm(rgb2, rgb3, unaligned_shift_index);
    261          out4 = vec_perm(rgb3, edges, unaligned_shift_index);
    262 #else
    263          out3 = vec_perm(rgb2, edges, unaligned_shift_index);
    264 #endif
    265          vec_st(out0, 0, outptr);
    266          if (bytes > 16)
    267            vec_st(out1, 16, outptr);
    268          if (bytes > 32)
    269            vec_st(out2, 32, outptr);
    270          if (bytes > 48)
    271            vec_st(out3, 48, outptr);
    272 #if RGB_PIXELSIZE == 4
    273          if (bytes > 64)
    274            vec_st(out4, 64, outptr);
    275 #endif
    276        }
    277      } else {
    278 #endif /* __BIG_ENDIAN__ */
    279        if (num_cols < RGB_PIXELSIZE * 16 && (num_cols & 15)) {
    280          /* Slow path */
    281          VEC_ST(rgb0, 0, tmpbuf);
    282          VEC_ST(rgb1, 16, tmpbuf);
    283          VEC_ST(rgb2, 32, tmpbuf);
    284 #if RGB_PIXELSIZE == 4
    285          VEC_ST(rgb3, 48, tmpbuf);
    286 #endif
    287          memcpy(outptr, tmpbuf, min(num_cols, RGB_PIXELSIZE * 16));
    288        } else {
    289          /* Fast path */
    290          VEC_ST(rgb0, 0, outptr);
    291          if (num_cols > 16)
    292            VEC_ST(rgb1, 16, outptr);
    293          if (num_cols > 32)
    294            VEC_ST(rgb2, 32, outptr);
    295 #if RGB_PIXELSIZE == 4
    296          if (num_cols > 48)
    297            VEC_ST(rgb3, 48, outptr);
    298 #endif
    299        }
    300 #if __BIG_ENDIAN__
    301      }
    302 #endif
    303    }
    304  }
    305 }
    306 
    307 
    308 void jsimd_h2v2_merged_upsample_altivec(JDIMENSION output_width,
    309                                        JSAMPIMAGE input_buf,
    310                                        JDIMENSION in_row_group_ctr,
    311                                        JSAMPARRAY output_buf)
    312 {
    313  JSAMPROW inptr, outptr;
    314 
    315  inptr = input_buf[0][in_row_group_ctr];
    316  outptr = output_buf[0];
    317 
    318  input_buf[0][in_row_group_ctr] = input_buf[0][in_row_group_ctr * 2];
    319  jsimd_h2v1_merged_upsample_altivec(output_width, input_buf, in_row_group_ctr,
    320                                     output_buf);
    321 
    322  input_buf[0][in_row_group_ctr] = input_buf[0][in_row_group_ctr * 2 + 1];
    323  output_buf[0] = output_buf[1];
    324  jsimd_h2v1_merged_upsample_altivec(output_width, input_buf, in_row_group_ctr,
    325                                     output_buf);
    326 
    327  input_buf[0][in_row_group_ctr] = inptr;
    328  output_buf[0] = outptr;
    329 }