Commit 06ad887f44203966b194cdcf95309046a2a1a2ca
2021-01-27T11:39:03
Fixed bug 3816 - asm code in video/SDL_stretch.c Ozkan Sezer - adds MSVC __declspec(align(x)) support, - disables asm if PAGE_ALIGNED no macro is defined, - still disables asm for gcc < 4.6, need more info, - drops Watcom support.
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diff --git a/src/video/SDL_stretch.c b/src/video/SDL_stretch.c
index 1d3610d..9e29e6e 100644
--- a/src/video/SDL_stretch.c
+++ b/src/video/SDL_stretch.c
@@ -34,54 +34,58 @@
into the general blitting mechanism.
*/
-#if ((defined(_MSC_VER) && defined(_M_IX86)) || \
- (defined(__WATCOMC__) && defined(__386__)) || \
+#if ((defined(_MSC_VER) && defined(_M_IX86)) || \
(defined(__GNUC__) && defined(__i386__))) && SDL_ASSEMBLY_ROUTINES
+#define USE_ASM_STRETCH
+#endif
+
/* There's a bug with gcc 4.4.1 and -O2 where srcp doesn't get the correct
* value after the first scanline. */
/* This bug seems fixed, at least with gcc >= 4.6 */
-# define USE_ASM_STRETCH
-# if defined(__GNUC__)
-# if (__GNUC__ < 4 || (__GNUC__ == 4 && __GNUC_MINOR__ < 6))
-# undef USE_ASM_STRETCH
-# endif
-# endif
-/* But it doesn't work if mprotect isn't available */
-# if !defined(HAVE_MPROTECT) && defined(USE_ASM_STRETCH)
-# undef USE_ASM_STRETCH
-# endif
+#if defined(USE_ASM_STRETCH) && \
+ defined(__GNUC__) && (__GNUC__ < 4 || (__GNUC__ == 4 && __GNUC_MINOR__ < 6))
+#undef USE_ASM_STRETCH
+#endif
+
+/* And it doesn't work if mprotect isn't available */
+#if defined(USE_ASM_STRETCH) && \
+ !defined(HAVE_MPROTECT) && !defined(__WIN32__)
+#undef USE_ASM_STRETCH
#endif
#ifdef USE_ASM_STRETCH
-#ifdef HAVE_MPROTECT
+#ifdef __WIN32__
+#define WIN32_LEAN_AND_MEAN
+#include <windows.h>
+#elif defined(HAVE_MPROTECT)
#include <sys/types.h>
#include <sys/mman.h>
#endif
#ifdef __GNUC__
#define PAGE_ALIGNED __attribute__((__aligned__(4096)))
+#elif defined(_MSC_VER)
+#define PAGE_ALIGNED __declspec(align(4096))
#else
-#define PAGE_ALIGNED
+#undef USE_ASM_STRETCH
#endif
+#endif /**/
+
+#ifdef USE_ASM_STRETCH
-#if defined(_M_IX86) || defined(__i386__) || defined(__386__)
#define PREFIX16 0x66
#define STORE_BYTE 0xAA
#define STORE_WORD 0xAB
#define LOAD_BYTE 0xAC
#define LOAD_WORD 0xAD
#define RETURN 0xC3
-#else
-#error Need assembly opcodes for this architecture
-#endif
-static unsigned char copy_row[4096] PAGE_ALIGNED;
+static PAGE_ALIGNED unsigned char copy_row[4096];
static int
generate_rowbytes(int src_w, int dst_w, int bpp)
{
- static struct
- {
+ static struct {
int bpp;
int src_w;
int dst_w;
@@ -92,6 +96,9 @@ generate_rowbytes(int src_w, int dst_w, int bpp)
int pos, inc;
unsigned char *eip, *fence;
unsigned char load, store;
+#ifdef __WIN32__
+ DWORD oldprot;
+#endif
/* See if we need to regenerate the copy buffer */
if ((src_w == last.src_w) && (dst_w == last.dst_w) && (bpp == last.bpp)) {
@@ -115,8 +122,12 @@ generate_rowbytes(int src_w, int dst_w, int bpp)
default:
return SDL_SetError("ASM stretch of %d bytes isn't supported", bpp);
}
-#ifdef HAVE_MPROTECT
/* Make the code writeable */
+#ifdef __WIN32__
+ if (!VirtualProtect(copy_row, sizeof(copy_row), PAGE_READWRITE, &oldprot)) {
+ return SDL_SetError("Couldn't make copy buffer writeable");
+ }
+#elif defined(HAVE_MPROTECT)
if (mprotect(copy_row, sizeof(copy_row), PROT_READ | PROT_WRITE) < 0) {
return SDL_SetError("Couldn't make copy buffer writeable");
}
@@ -147,8 +158,12 @@ generate_rowbytes(int src_w, int dst_w, int bpp)
}
*eip++ = RETURN;
-#ifdef HAVE_MPROTECT
/* Make the code executable but not writeable */
+#ifdef __WIN32__
+ if (!VirtualProtect(copy_row, sizeof(copy_row), PAGE_EXECUTE_READ, &oldprot)) {
+ return SDL_SetError("Couldn't make copy buffer executable");
+ }
+#elif defined(HAVE_MPROTECT)
if (mprotect(copy_row, sizeof(copy_row), PROT_READ | PROT_EXEC) < 0) {
return SDL_SetError("Couldn't make copy buffer executable");
}
@@ -156,7 +171,6 @@ generate_rowbytes(int src_w, int dst_w, int bpp)
last.status = 0;
return (0);
}
-
#endif /* USE_ASM_STRETCH */
#define DEFINE_COPY_ROW(name, type) \