SDL BlitCopy

gistfile1.c

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) {
        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;
    }
}