kc3-lang/SDL/src/video/SDL_blit_copy.c

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• Hash : cd64e0b6
  Author :
  Date : 2023-03-26T16:31:18
  

  SDL_blit_copy: Don't call potentially FPU using SDL_memcpy in SDL_memcpyMMX

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• src/video/SDL_blit_copy.c

• /*
    Simple DirectMedia Layer
    Copyright (C) 1997-2023 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"
  
  #include "SDL_video.h"
  #include "SDL_blit.h"
  #include "SDL_blit_copy.h"
  
  #ifdef __SSE__
  /* This assumes 16-byte aligned src and dst */
  static SDL_INLINE void SDL_memcpySSE(Uint8 *dst, const Uint8 *src, int len)
  {
      int i;
  
      __m128 values[4];
      for (i = len / 64; i--;) {
          _mm_prefetch((const char *)src, _MM_HINT_NTA);
          values[0] = *(__m128 *)(src + 0);
          values[1] = *(__m128 *)(src + 16);
          values[2] = *(__m128 *)(src + 32);
          values[3] = *(__m128 *)(src + 48);
          _mm_stream_ps((float *)(dst + 0), values[0]);
          _mm_stream_ps((float *)(dst + 16), values[1]);
          _mm_stream_ps((float *)(dst + 32), values[2]);
          _mm_stream_ps((float *)(dst + 48), values[3]);
          src += 64;
          dst += 64;
      }
  
      if (len & 63) {
          SDL_memcpy(dst, src, len & 63);
      }
  }
  #endif /* __SSE__ */
  
  #ifdef __MMX__
  #ifdef _MSC_VER
  #pragma warning(disable : 4799)
  #endif
  static SDL_INLINE void SDL_memcpyMMX(Uint8 *dst, const Uint8 *src, int len)
  {
      int remain = len & 63;
      int i;
  
      __m64 *d64 = (__m64 *)dst;
      __m64 *s64 = (__m64 *)src;
  
      for (i = len / 64; i--;) {
          d64[0] = s64[0];
          d64[1] = s64[1];
          d64[2] = s64[2];
          d64[3] = s64[3];
          d64[4] = s64[4];
          d64[5] = s64[5];
          d64[6] = s64[6];
          d64[7] = s64[7];
  
          d64 += 8;
          s64 += 8;
      }
  
      if (remain) {
          const int skip = len - remain;
          dst += skip;
          src += skip;
          while (remain--) {
              *dst++ = *src++;
          }
      }
  }
  #endif /* __MMX__ */
  
  void SDL_BlitCopy(SDL_BlitInfo *info)
  {
      SDL_bool overlap;
      Uint8 *src, *dst;
      int w, h;
      int srcskip, dstskip;
  
      w = info->dst_w * info->dst_fmt->BytesPerPixel;
      h = info->dst_h;
      src = info->src;
      dst = info->dst;
      srcskip = info->src_pitch;
      dstskip = info->dst_pitch;
  
      /* Properly handle overlapping blits */
      if (src < dst) {
          overlap = (dst < (src + h * srcskip));
      } else {
          overlap = (src < (dst + h * dstskip));
      }
      if (overlap) {
          if (dst < src) {
              while (h--) {
                  SDL_memmove(dst, src, w);
                  src += srcskip;
                  dst += dstskip;
              }
          } else {
              src += ((h - 1) * srcskip);
              dst += ((h - 1) * dstskip);
              while (h--) {
                  SDL_memmove(dst, src, w);
                  src -= srcskip;
                  dst -= dstskip;
              }
          }
          return;
      }
  
  #ifdef __SSE__
      if (SDL_HasSSE() &&
          !((uintptr_t)src & 15) && !(srcskip & 15) &&
          !((uintptr_t)dst & 15) && !(dstskip & 15)) {
          while (h--) {
              SDL_memcpySSE(dst, src, w);
              src += srcskip;
              dst += dstskip;
          }
          return;
      }
  #endif
  
  #ifdef __MMX__
      if (SDL_HasMMX() && !(srcskip & 7) && !(dstskip & 7)) {
          while (h--) {
              SDL_memcpyMMX(dst, src, w);
              src += srcskip;
              dst += dstskip;
          }
          _mm_empty();
          return;
      }
  #endif
  
      while (h--) {
          SDL_memcpy(dst, src, w);
          src += srcskip;
          dst += dstskip;
      }
  }
  
  /* vi: set ts=4 sw=4 expandtab: */
  

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