initial commit, 4.5 stable

thirdparty/sdl/stdlib/SDL_memcpy.c

@@ -0,0 +1,101 @@
+/*
+  Simple DirectMedia Layer
+  Copyright (C) 1997-2025 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"
+
+
+#ifdef SDL_memcpy
+#undef SDL_memcpy
+#endif
+#if SDL_DYNAMIC_API
+#define SDL_memcpy SDL_memcpy_REAL
+#endif
+void *SDL_memcpy(SDL_OUT_BYTECAP(len) void *dst, SDL_IN_BYTECAP(len) const void *src, size_t len)
+{
+#if defined(__GNUC__) && (defined(HAVE_LIBC) && HAVE_LIBC)
+    /* Presumably this is well tuned for speed.
+       On my machine this is twice as fast as the C code below.
+     */
+    return __builtin_memcpy(dst, src, len);
+#elif defined(HAVE_MEMCPY)
+    return memcpy(dst, src, len);
+#elif defined(HAVE_BCOPY)
+    bcopy(src, dst, len);
+    return dst;
+#else
+    /* GCC 4.9.0 with -O3 will generate movaps instructions with the loop
+       using Uint32* pointers, so we need to make sure the pointers are
+       aligned before we loop using them.
+     */
+    if (((uintptr_t)src & 0x3) || ((uintptr_t)dst & 0x3)) {
+        // Do an unaligned byte copy
+        Uint8 *srcp1 = (Uint8 *)src;
+        Uint8 *dstp1 = (Uint8 *)dst;
+
+        while (len--) {
+            *dstp1++ = *srcp1++;
+        }
+    } else {
+        size_t left = (len % 4);
+        Uint32 *srcp4, *dstp4;
+        Uint8 *srcp1, *dstp1;
+
+        srcp4 = (Uint32 *)src;
+        dstp4 = (Uint32 *)dst;
+        len /= 4;
+        while (len--) {
+            *dstp4++ = *srcp4++;
+        }
+
+        srcp1 = (Uint8 *)srcp4;
+        dstp1 = (Uint8 *)dstp4;
+        switch (left) {
+        case 3:
+            *dstp1++ = *srcp1++;
+            SDL_FALLTHROUGH;
+        case 2:
+            *dstp1++ = *srcp1++;
+            SDL_FALLTHROUGH;
+        case 1:
+            *dstp1++ = *srcp1++;
+        }
+    }
+    return dst;
+#endif // HAVE_MEMCPY
+}
+
+/* The optimizer on Visual Studio 2005 and later generates memcpy() and memset() calls.
+   We will provide our own implementation if we're not building with a C runtime. */
+#ifndef HAVE_LIBC
+// NOLINTNEXTLINE(readability-redundant-declaration)
+extern void *memcpy(void *dst, const void *src, size_t len);
+#if defined(_MSC_VER) && !defined(__INTEL_LLVM_COMPILER)
+#pragma intrinsic(memcpy)
+#endif
+
+#if defined(_MSC_VER) && !defined(__clang__)
+#pragma function(memcpy)
+#endif
+// NOLINTNEXTLINE(readability-inconsistent-declaration-parameter-name)
+void *memcpy(void *dst, const void *src, size_t len)
+{
+    return SDL_memcpy(dst, src, len);
+}
+#endif // !HAVE_LIBC