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Merged improvements to SDL_SoftStretch() from SDL 1.2
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@slouken
slouken committed Oct 18, 2009
1 parent 6ece67f commit 6803a1c
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Showing 3 changed files with 87 additions and 51 deletions.
9 changes: 9 additions & 0 deletions configure.in
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Expand Up @@ -204,6 +204,15 @@ if test x$enable_libc = xyes; then
if test x$ac_cv_func_strtod = xyes; then
AC_DEFINE(HAVE_STRTOD)
fi
AC_CHECK_FUNC(mprotect,
AC_TRY_COMPILE([
#include <sys/types.h>
#include <sys/mman.h>
],[
],[
AC_DEFINE(HAVE_MPROTECT)
]),
)
AC_CHECK_FUNCS(malloc calloc realloc free getenv putenv unsetenv qsort abs bcopy memset memcpy memmove strlen strlcpy strlcat strdup _strrev _strupr _strlwr strchr strrchr strstr itoa _ltoa _uitoa _ultoa strtol strtoul _i64toa _ui64toa strtoll strtoull atoi atof strcmp strncmp _stricmp strcasecmp _strnicmp strncasecmp sscanf snprintf vsnprintf sigaction setjmp nanosleep)

AC_CHECK_LIB(m, pow, [LIBS="$LIBS -lm"; EXTRA_LDFLAGS="$EXTRA_LDFLAGS -lm"])
Expand Down
1 change: 1 addition & 0 deletions include/SDL_config.h.in
View file
Expand Up @@ -151,6 +151,7 @@
#undef HAVE_NANOSLEEP
#undef HAVE_CLOCK_GETTIME
#undef HAVE_GETPAGESIZE
#undef HAVE_MPROTECT

#else
/* We may need some replacement for stdarg.h here */
Expand Down
128 changes: 77 additions & 51 deletions src/video/SDL_stretch.c
View file
Expand Up @@ -42,6 +42,16 @@

#ifdef USE_ASM_STRETCH

#ifdef HAVE_MPROTECT
#include <sys/types.h>
#include <sys/mman.h>
#endif
#ifdef __GNUC__
#define PAGE_ALIGNED __attribute__((__aligned__(4096)))
#else
#define PAGE_ALIGNED
#endif

#if defined(_M_IX86) || defined(i386)
#define PREFIX16 0x66
#define STORE_BYTE 0xAA
Expand All @@ -53,7 +63,7 @@
#error Need assembly opcodes for this architecture
#endif

static unsigned char copy_row[4096];
static unsigned char copy_row[4096] PAGE_ALIGNED;

static int
generate_rowbytes(int src_w, int dst_w, int bpp)
Expand All @@ -63,6 +73,7 @@ generate_rowbytes(int src_w, int dst_w, int bpp)
int bpp;
int src_w;
int dst_w;
int status;
} last;

int i;
Expand All @@ -72,11 +83,12 @@ generate_rowbytes(int src_w, int dst_w, int bpp)

/* See if we need to regenerate the copy buffer */
if ((src_w == last.src_w) && (dst_w == last.dst_w) && (bpp == last.bpp)) {
return (0);
return (last.status);
}
last.bpp = bpp;
last.src_w = src_w;
last.dst_w = dst_w;
last.status = -1;

switch (bpp) {
case 1:
Expand All @@ -92,6 +104,13 @@ generate_rowbytes(int src_w, int dst_w, int bpp)
SDL_SetError("ASM stretch of %d bytes isn't supported\n", bpp);
return (-1);
}
#ifdef HAVE_MPROTECT
/* Make the code writeable */
if (mprotect(copy_row, sizeof(copy_row), PROT_READ | PROT_WRITE) < 0) {
SDL_SetError("Couldn't make copy buffer writeable");
return (-1);
}
#endif
pos = 0x10000;
inc = (src_w << 16) / dst_w;
eip = copy_row;
Expand All @@ -111,47 +130,55 @@ generate_rowbytes(int src_w, int dst_w, int bpp)
}
*eip++ = RETURN;

/* Verify that we didn't overflow (too late) */
/* Verify that we didn't overflow (too late!!!) */
if (eip > (copy_row + sizeof(copy_row))) {
SDL_SetError("Copy buffer overflow");
return (-1);
}
#ifdef HAVE_MPROTECT
/* Make the code executable but not writeable */
if (mprotect(copy_row, sizeof(copy_row), PROT_READ | PROT_EXEC) < 0) {
SDL_SetError("Couldn't make copy buffer executable");
return (-1);
}
#endif
last.status = 0;
return (0);
}

#else
#endif /* USE_ASM_STRETCH */

#define DEFINE_COPY_ROW(name, type) \
void name(type *src, int src_w, type *dst, int dst_w) \
{ \
int i; \
int pos, inc; \
type pixel = 0; \
\
pos = 0x10000; \
inc = (src_w << 16) / dst_w; \
for ( i=dst_w; i>0; --i ) { \
while ( pos >= 0x10000L ) { \
pixel = *src++; \
pos -= 0x10000L; \
} \
*dst++ = pixel; \
pos += inc; \
} \
#define DEFINE_COPY_ROW(name, type) \
void name(type *src, int src_w, type *dst, int dst_w) \
{ \
int i; \
int pos, inc; \
type pixel = 0; \
\
pos = 0x10000; \
inc = (src_w << 16) / dst_w; \
for ( i=dst_w; i>0; --i ) { \
while ( pos >= 0x10000L ) { \
pixel = *src++; \
pos -= 0x10000L; \
} \
*dst++ = pixel; \
pos += inc; \
} \
}
/* *INDENT-OFF* */
DEFINE_COPY_ROW(copy_row1, Uint8)
DEFINE_COPY_ROW(copy_row2, Uint16)
DEFINE_COPY_ROW(copy_row4, Uint32)
/* *INDENT-ON* */
#endif /* USE_ASM_STRETCH */

/* The ASM code doesn't handle 24-bpp stretch blits */
void
copy_row3(Uint8 * src, int src_w, Uint8 * dst, int dst_w)
{
int i;
int pos, inc;
Uint8 pixel[3];
Uint8 pixel[3] = { 0, 0, 0 };

pos = 0x10000;
inc = (src_w << 16) / dst_w;
Expand Down Expand Up @@ -186,9 +213,12 @@ SDL_SoftStretch(SDL_Surface * src, const SDL_Rect * srcrect,
Uint8 *dstp;
SDL_Rect full_src;
SDL_Rect full_dst;
#if defined(USE_ASM_STRETCH) && defined(__GNUC__)
#ifdef USE_ASM_STRETCH
SDL_bool use_asm = SDL_TRUE;
#ifdef __GNUC__
int u1, u2;
#endif
#endif /* USE_ASM_STRETCH */
const int bpp = dst->format->BytesPerPixel;

if (src->format->BitsPerPixel != dst->format->BitsPerPixel) {
Expand Down Expand Up @@ -257,8 +287,8 @@ SDL_SoftStretch(SDL_Surface * src, const SDL_Rect * srcrect,

#ifdef USE_ASM_STRETCH
/* Write the opcodes for this stretch */
if ((bpp != 3) && (generate_rowbytes(srcrect->w, dstrect->w, bpp) < 0)) {
return (-1);
if ((bpp == 3) || (generate_rowbytes(srcrect->w, dstrect->w, bpp) < 0)) {
use_asm = SDL_FALSE;
}
#endif

Expand All @@ -273,13 +303,11 @@ SDL_SoftStretch(SDL_Surface * src, const SDL_Rect * srcrect,
pos -= 0x10000L;
}
#ifdef USE_ASM_STRETCH
switch (bpp) {
case 3:
copy_row3(srcp, srcrect->w, dstp, dstrect->w);
break;
default:
if (use_asm) {
#ifdef __GNUC__
__asm__ __volatile__("call *%4": "=&D"(u1), "=&S"(u2): "0"(dstp), "1"(srcp), "r"(copy_row):"memory");
__asm__ __volatile__("call *%4":"=&D"(u1), "=&S"(u2)
:"0"(dstp), "1"(srcp), "r"(copy_row)
:"memory");
#elif defined(_MSC_VER) || defined(__WATCOMC__)
/* *INDENT-OFF* */
{
Expand All @@ -298,26 +326,24 @@ SDL_SoftStretch(SDL_Surface * src, const SDL_Rect * srcrect,
#else
#error Need inline assembly for this compiler
#endif
break;
}
#else
switch (bpp) {
case 1:
copy_row1(srcp, srcrect->w, dstp, dstrect->w);
break;
case 2:
copy_row2((Uint16 *) srcp, srcrect->w,
(Uint16 *) dstp, dstrect->w);
break;
case 3:
copy_row3(srcp, srcrect->w, dstp, dstrect->w);
break;
case 4:
copy_row4((Uint32 *) srcp, srcrect->w,
(Uint32 *) dstp, dstrect->w);
break;
}
} else
#endif
switch (bpp) {
case 1:
copy_row1(srcp, srcrect->w, dstp, dstrect->w);
break;
case 2:
copy_row2((Uint16 *) srcp, srcrect->w,
(Uint16 *) dstp, dstrect->w);
break;
case 3:
copy_row3(srcp, srcrect->w, dstp, dstrect->w);
break;
case 4:
copy_row4((Uint32 *) srcp, srcrect->w,
(Uint32 *) dstp, dstrect->w);
break;
}
pos += inc;
}

Expand Down

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