kc3-lang/libjpeg-turbo/simd/arm/jfdctfst-neon.c

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• Hash : e69dd40c
  Author :
  Date : 2024-01-23T13:26:41
  

  Reorganize source to make things easier to find
  
  - Move all libjpeg documentation, except for README.ijg, into the doc/
    subdirectory.
  
  - Move the TurboJPEG C API documentation from doc/html/ into
    doc/turbojpeg/.
  
  - Move all C source code and headers into a src/ subdirectory.
  
  - Move turbojpeg-jni.c into the java/ subdirectory.
  
  Referring to #226, there is no ideal solution to this problem.  A
  semantically ideal solution would have involved placing all source code,
  including the SIMD and Java source code, under src/ (or perhaps placing
  C library source code under lib/ and C test program source code under
  test/), all header files under include/, and all documentation under
  doc/.  However:
  
  - To me it makes more sense to have separate top-level directories for
    each language, since the SIMD extensions and the Java API are
    technically optional features.  src/ now contains only the code that
    is relevant to the core C API libraries and associated programs.
  - I didn't want to bury the java/ and simd/ directories or add a level
    of depth to them, since both directories already contain source code
    that is 3-4 levels deep.
  - I would prefer not to separate the header files from the C source
    code, because:
    1. It would be disruptive.  libjpeg and libjpeg-turbo have
       historically placed C source code and headers in the same
       directory, and people who are familiar with both projects (self
       included) are used to looking for the headers in the same directory
       as the C source code.
    2. In terms of how the headers are used internally in libjpeg-turbo,
       the distinction between public and private headers is a bit fuzzy.
  - It didn't make sense to separate the test source code from the library
    source code, since there is not a clear distinction in some cases.
    (For instance, the IJG image I/O functions are used by cjpeg and djpeg
    as well as by the TurboJPEG API.)
  
  This solution is minimally disruptive, since it keeps all C source code
  and headers together and keeps java/ and simd/ as top-level directories.
  It is a bit awkward, because java/ and simd/ technically contain source
  code, even though they are not under src/.  However, other solutions
  would have been more awkward for different reasons.
  
  Closes #226
  

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• simd/arm/jfdctfst-neon.c

• /*
   * jfdctfst-neon.c - fast integer FDCT (Arm Neon)
   *
   * Copyright (C) 2020, Arm Limited.  All Rights Reserved.
   * Copyright (C) 2024, D. R. Commander.  All Rights Reserved.
   *
   * This software is provided 'as-is', without any express or implied
   * warranty.  In no event will the authors be held liable for any damages
   * arising from the use of this software.
   *
   * Permission is granted to anyone to use this software for any purpose,
   * including commercial applications, and to alter it and redistribute it
   * freely, subject to the following restrictions:
   *
   * 1. The origin of this software must not be misrepresented; you must not
   *    claim that you wrote the original software. If you use this software
   *    in a product, an acknowledgment in the product documentation would be
   *    appreciated but is not required.
   * 2. Altered source versions must be plainly marked as such, and must not be
   *    misrepresented as being the original software.
   * 3. This notice may not be removed or altered from any source distribution.
   */
  
  #define JPEG_INTERNALS
  #include "../../src/jinclude.h"
  #include "../../src/jpeglib.h"
  #include "../../src/jsimd.h"
  #include "../../src/jdct.h"
  #include "../../src/jsimddct.h"
  #include "../jsimd.h"
  #include "align.h"
  
  #include <arm_neon.h>
  
  
  /* jsimd_fdct_ifast_neon() performs a fast, not so accurate forward DCT
   * (Discrete Cosine Transform) on one block of samples.  It uses the same
   * calculations and produces exactly the same output as IJG's original
   * jpeg_fdct_ifast() function, which can be found in jfdctfst.c.
   *
   * Scaled integer constants are used to avoid floating-point arithmetic:
   *    0.382683433 = 12544 * 2^-15
   *    0.541196100 = 17795 * 2^-15
   *    0.707106781 = 23168 * 2^-15
   *    0.306562965 =  9984 * 2^-15
   *
   * See jfdctfst.c for further details of the DCT algorithm.  Where possible,
   * the variable names and comments here in jsimd_fdct_ifast_neon() match up
   * with those in jpeg_fdct_ifast().
   */
  
  #define F_0_382  12544
  #define F_0_541  17792
  #define F_0_707  23168
  #define F_0_306  9984
  
  
  ALIGN(16) static const int16_t jsimd_fdct_ifast_neon_consts[] = {
    F_0_382, F_0_541, F_0_707, F_0_306
  };
  
  void jsimd_fdct_ifast_neon(DCTELEM *data)
  {
    /* Load an 8x8 block of samples into Neon registers.  De-interleaving loads
     * are used, followed by vuzp to transpose the block such that we have a
     * column of samples per vector - allowing all rows to be processed at once.
     */
    int16x8x4_t data1 = vld4q_s16(data);
    int16x8x4_t data2 = vld4q_s16(data + 4 * DCTSIZE);
  
    int16x8x2_t cols_04 = vuzpq_s16(data1.val[0], data2.val[0]);
    int16x8x2_t cols_15 = vuzpq_s16(data1.val[1], data2.val[1]);
    int16x8x2_t cols_26 = vuzpq_s16(data1.val[2], data2.val[2]);
    int16x8x2_t cols_37 = vuzpq_s16(data1.val[3], data2.val[3]);
  
    int16x8_t col0 = cols_04.val[0];
    int16x8_t col1 = cols_15.val[0];
    int16x8_t col2 = cols_26.val[0];
    int16x8_t col3 = cols_37.val[0];
    int16x8_t col4 = cols_04.val[1];
    int16x8_t col5 = cols_15.val[1];
    int16x8_t col6 = cols_26.val[1];
    int16x8_t col7 = cols_37.val[1];
  
    /* Pass 1: process rows. */
  
    /* Load DCT conversion constants. */
    const int16x4_t consts = vld1_s16(jsimd_fdct_ifast_neon_consts);
  
    int16x8_t tmp0 = vaddq_s16(col0, col7);
    int16x8_t tmp7 = vsubq_s16(col0, col7);
    int16x8_t tmp1 = vaddq_s16(col1, col6);
    int16x8_t tmp6 = vsubq_s16(col1, col6);
    int16x8_t tmp2 = vaddq_s16(col2, col5);
    int16x8_t tmp5 = vsubq_s16(col2, col5);
    int16x8_t tmp3 = vaddq_s16(col3, col4);
    int16x8_t tmp4 = vsubq_s16(col3, col4);
  
    /* Even part */
    int16x8_t tmp10 = vaddq_s16(tmp0, tmp3);    /* phase 2 */
    int16x8_t tmp13 = vsubq_s16(tmp0, tmp3);
    int16x8_t tmp11 = vaddq_s16(tmp1, tmp2);
    int16x8_t tmp12 = vsubq_s16(tmp1, tmp2);
  
    col0 = vaddq_s16(tmp10, tmp11);             /* phase 3 */
    col4 = vsubq_s16(tmp10, tmp11);
  
    int16x8_t z1 = vqdmulhq_lane_s16(vaddq_s16(tmp12, tmp13), consts, 2);
    col2 = vaddq_s16(tmp13, z1);                /* phase 5 */
    col6 = vsubq_s16(tmp13, z1);
  
    /* Odd part */
    tmp10 = vaddq_s16(tmp4, tmp5);              /* phase 2 */
    tmp11 = vaddq_s16(tmp5, tmp6);
    tmp12 = vaddq_s16(tmp6, tmp7);
  
    int16x8_t z5 = vqdmulhq_lane_s16(vsubq_s16(tmp10, tmp12), consts, 0);
    int16x8_t z2 = vqdmulhq_lane_s16(tmp10, consts, 1);
    z2 = vaddq_s16(z2, z5);
    int16x8_t z4 = vqdmulhq_lane_s16(tmp12, consts, 3);
    z5 = vaddq_s16(tmp12, z5);
    z4 = vaddq_s16(z4, z5);
    int16x8_t z3 = vqdmulhq_lane_s16(tmp11, consts, 2);
  
    int16x8_t z11 = vaddq_s16(tmp7, z3);        /* phase 5 */
    int16x8_t z13 = vsubq_s16(tmp7, z3);
  
    col5 = vaddq_s16(z13, z2);                  /* phase 6 */
    col3 = vsubq_s16(z13, z2);
    col1 = vaddq_s16(z11, z4);
    col7 = vsubq_s16(z11, z4);
  
    /* Transpose to work on columns in pass 2. */
    int16x8x2_t cols_01 = vtrnq_s16(col0, col1);
    int16x8x2_t cols_23 = vtrnq_s16(col2, col3);
    int16x8x2_t cols_45 = vtrnq_s16(col4, col5);
    int16x8x2_t cols_67 = vtrnq_s16(col6, col7);
  
    int32x4x2_t cols_0145_l = vtrnq_s32(vreinterpretq_s32_s16(cols_01.val[0]),
                                        vreinterpretq_s32_s16(cols_45.val[0]));
    int32x4x2_t cols_0145_h = vtrnq_s32(vreinterpretq_s32_s16(cols_01.val[1]),
                                        vreinterpretq_s32_s16(cols_45.val[1]));
    int32x4x2_t cols_2367_l = vtrnq_s32(vreinterpretq_s32_s16(cols_23.val[0]),
                                        vreinterpretq_s32_s16(cols_67.val[0]));
    int32x4x2_t cols_2367_h = vtrnq_s32(vreinterpretq_s32_s16(cols_23.val[1]),
                                        vreinterpretq_s32_s16(cols_67.val[1]));
  
    int32x4x2_t rows_04 = vzipq_s32(cols_0145_l.val[0], cols_2367_l.val[0]);
    int32x4x2_t rows_15 = vzipq_s32(cols_0145_h.val[0], cols_2367_h.val[0]);
    int32x4x2_t rows_26 = vzipq_s32(cols_0145_l.val[1], cols_2367_l.val[1]);
    int32x4x2_t rows_37 = vzipq_s32(cols_0145_h.val[1], cols_2367_h.val[1]);
  
    int16x8_t row0 = vreinterpretq_s16_s32(rows_04.val[0]);
    int16x8_t row1 = vreinterpretq_s16_s32(rows_15.val[0]);
    int16x8_t row2 = vreinterpretq_s16_s32(rows_26.val[0]);
    int16x8_t row3 = vreinterpretq_s16_s32(rows_37.val[0]);
    int16x8_t row4 = vreinterpretq_s16_s32(rows_04.val[1]);
    int16x8_t row5 = vreinterpretq_s16_s32(rows_15.val[1]);
    int16x8_t row6 = vreinterpretq_s16_s32(rows_26.val[1]);
    int16x8_t row7 = vreinterpretq_s16_s32(rows_37.val[1]);
  
    /* Pass 2: process columns. */
  
    tmp0 = vaddq_s16(row0, row7);
    tmp7 = vsubq_s16(row0, row7);
    tmp1 = vaddq_s16(row1, row6);
    tmp6 = vsubq_s16(row1, row6);
    tmp2 = vaddq_s16(row2, row5);
    tmp5 = vsubq_s16(row2, row5);
    tmp3 = vaddq_s16(row3, row4);
    tmp4 = vsubq_s16(row3, row4);
  
    /* Even part */
    tmp10 = vaddq_s16(tmp0, tmp3);              /* phase 2 */
    tmp13 = vsubq_s16(tmp0, tmp3);
    tmp11 = vaddq_s16(tmp1, tmp2);
    tmp12 = vsubq_s16(tmp1, tmp2);
  
    row0 = vaddq_s16(tmp10, tmp11);             /* phase 3 */
    row4 = vsubq_s16(tmp10, tmp11);
  
    z1 = vqdmulhq_lane_s16(vaddq_s16(tmp12, tmp13), consts, 2);
    row2 = vaddq_s16(tmp13, z1);                /* phase 5 */
    row6 = vsubq_s16(tmp13, z1);
  
    /* Odd part */
    tmp10 = vaddq_s16(tmp4, tmp5);              /* phase 2 */
    tmp11 = vaddq_s16(tmp5, tmp6);
    tmp12 = vaddq_s16(tmp6, tmp7);
  
    z5 = vqdmulhq_lane_s16(vsubq_s16(tmp10, tmp12), consts, 0);
    z2 = vqdmulhq_lane_s16(tmp10, consts, 1);
    z2 = vaddq_s16(z2, z5);
    z4 = vqdmulhq_lane_s16(tmp12, consts, 3);
    z5 = vaddq_s16(tmp12, z5);
    z4 = vaddq_s16(z4, z5);
    z3 = vqdmulhq_lane_s16(tmp11, consts, 2);
  
    z11 = vaddq_s16(tmp7, z3);                  /* phase 5 */
    z13 = vsubq_s16(tmp7, z3);
  
    row5 = vaddq_s16(z13, z2);                  /* phase 6 */
    row3 = vsubq_s16(z13, z2);
    row1 = vaddq_s16(z11, z4);
    row7 = vsubq_s16(z11, z4);
  
    vst1q_s16(data + 0 * DCTSIZE, row0);
    vst1q_s16(data + 1 * DCTSIZE, row1);
    vst1q_s16(data + 2 * DCTSIZE, row2);
    vst1q_s16(data + 3 * DCTSIZE, row3);
    vst1q_s16(data + 4 * DCTSIZE, row4);
    vst1q_s16(data + 5 * DCTSIZE, row5);
    vst1q_s16(data + 6 * DCTSIZE, row6);
    vst1q_s16(data + 7 * DCTSIZE, row7);
  }
  

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