kc3-lang/SDL/src/stdlib/SDL_memset.c

• Show log

  Commit

• Hash : ae7446a9
  Author :
  Date : 2022-06-15T20:48:54
  

  stlib: Extract SDL_memcpy and SDL_memset to its own file respectively This is done such that we can disable LTO for these 2 functions when building with MSVC. This is due to a limitation of Link Time Code Generation (LTCG). Code generation might generate a new reference to memset after linking has started. The LTCG must make assumptions about where memset is defined which is normally the C runtime.

Download

• src/stdlib/SDL_memset.c

• /*
    Simple DirectMedia Layer
    Copyright (C) 1997-2022 Sam Lantinga <slouken@libsdl.org>
  
    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.
  */
  
  #include "../SDL_internal.h"
  
  /* This file contains a portable memset manipulation function for SDL */
  
  void *
  SDL_memset(SDL_OUT_BYTECAP(len) void *dst, int c, size_t len)
  {
  #if defined(HAVE_MEMSET)
      return memset(dst, c, len);
  #else
      size_t left;
      Uint32 *dstp4;
      Uint8 *dstp1 = (Uint8 *) dst;
      Uint8 value1;
      Uint32 value4;
  
      /* The value used in memset() is a byte, passed as an int */
      c &= 0xff;
  
      /* The destination pointer needs to be aligned on a 4-byte boundary to
       * execute a 32-bit set. Set first bytes manually if needed until it is
       * aligned. */
      value1 = (Uint8)c;
      while ((uintptr_t)dstp1 & 0x3) {
          if (len--) {
              *dstp1++ = value1;
          } else {
              return dst;
          }
      }
  
      value4 = ((Uint32)c | ((Uint32)c << 8) | ((Uint32)c << 16) | ((Uint32)c << 24));
      dstp4 = (Uint32 *) dstp1;
      left = (len % 4);
      len /= 4;
      while (len--) {
          *dstp4++ = value4;
      }
  
      dstp1 = (Uint8 *) dstp4;
      switch (left) {
          case 3:
              *dstp1++ = value1;
          case 2:
              *dstp1++ = value1;
          case 1:
              *dstp1++ = value1;
      }
  
      return dst;
  #endif /* HAVE_MEMSET */
  }
  
  /* vi: set ts=4 sw=4 expandtab: */
  

Download