kc3-lang/libjpeg-turbo/simd/arm/neon-compat.h.in

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• Hash : 33859880
  Author :
  Date : 2020-11-13T12:12:47
  

  Neon: Auto-detect compiler intrinsics completeness
  
  This allows the Neon intrinsics code to be built successfully (albeit
  likely with reduced run-time performance) with Xcode 5.0-6.2
  (iOS/AArch64) and Android NDK < r19 (AArch32).  Note that Xcode 5.0-6.2
  will not build the Armv8 GAS code without gas-preprocessor.pl, and no
  version of Xcode will build the Armv7 GAS code without
  gas-preprocessor.pl, so we always use the full Neon intrinsics
  implementation by default with macOS and iOS builds.
  
  Auto-detecting the completeness of the compiler's set of Neon intrinsics
  also allows us to more intelligently set the default value of
  NEON_INTRINSICS, based on the values of HAVE_VLD1*.  This is a
  reasonable, albeit imperfect, proxy for whether a compiler has a full
  and optimal set of Neon intrinsics.  Specific notes:
  
    - 64-bit RGB-to-YCbCr color conversion
      does not use any of the intrinsics in question, regresses with GCC
    - 64-bit accurate integer forward DCT
      uses vld1_s16_x3(), regresses with GCC
    - 64-bit Huffman encoding
      uses vld1q_u8_x4(), regresses with GCC
    - 64-bit YCbCr-to-RGB color conversion
      does not use any of the intrinsics in question, regresses with GCC
    - 64-bit accurate integer inverse DCT
      uses vld1_s16_x3(), regresses with GCC
    - 64-bit 4x4 inverse DCT
      uses vld1_s16_x3().  I did not test this algorithm in isolation, so
      it may in fact regress with GCC, but the regression may be hidden by
      the speedup from the new SIMD-accelerated upsampling algorithms.
  
    - 32-bit RGB-to-YCbCr color conversion:
      uses vld1_u16_x2(), regresses with GCC
    - 32-bit accurate integer forward DCT
      uses vld1_s16_x3(), regression irrelevant because there was no
      previous implementation
    - 32-bit accurate integer inverse DCT
      uses vld1_s16_x3(), regresses with GCC
    - 32-bit fast integer inverse DCT
      does not use any of the intrinsics in question, regresses with GCC
    - 32-bit 4x4 inverse DCT
      uses vld1_s16_x3().  I did not test this algorithm in isolation, so
      it may in fact regress with GCC, but the regression may be hidden by
      the speedup from the new SIMD-accelerated upsampling algorithms.
  
  Presumably when GCC includes a full and optimal set of Neon intrinsics,
  the HAVE_VLD1* tests will pass, and the full Neon intrinsics
  implementation will be enabled automatically.
  

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• simd/arm/neon-compat.h.in

• /*
   * Copyright (C) 2020, 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.
   */
  
  #cmakedefine HAVE_VLD1_S16_X3
  #cmakedefine HAVE_VLD1_U16_X2
  #cmakedefine HAVE_VLD1Q_U8_X4
  

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