SDL2 port for DOS (DJGPP and VBE 2.0+)

CMakeLists.txt

@@ -241,7 +241,7 @@ if(USE_GCC OR USE_CLANG OR USE_INTELCC OR USE_QCC)
 endif()
 
 # Default option knobs
-if(UNIX OR MINGW OR MSYS OR (USE_CLANG AND NOT WINDOWS) OR VITA OR PSP OR PS2 OR N3DS OR SDL_CPU_ARM64EC)
+if(UNIX OR MINGW OR MSYS OR (USE_CLANG AND NOT WINDOWS) OR VITA OR PSP OR PS2 OR N3DS OR SDL_CPU_ARM64EC OR DOS)
   set(OPT_DEF_LIBC ON)
 endif()
 if(WINDOWS OR MACOS OR IOS OR TVOS OR VISIONOS OR WATCHOS)
@@ -358,11 +358,20 @@ if(EMSCRIPTEN)
   set(SDL_CPUINFO_ENABLED_BY_DEFAULT OFF)
 endif()
 
-if(VITA OR PSP OR PS2 OR N3DS)
+if(VITA OR PSP OR PS2 OR N3DS OR DOS)
   set(SDL_SHARED_ENABLED_BY_DEFAULT OFF)
   set(SDL_LOADSO_ENABLED_BY_DEFAULT OFF)
 endif()
 
+if(DOS)
+  set(SDL_THREADS_ENABLED_BY_DEFAULT OFF)
+  set(SDL_SSE OFF)
+  set(SDL_SSE2 OFF)
+  set(SDL_SSE3 OFF)
+  set(SDL_MMX OFF)
+  set(SDL_3DNOW OFF)
+endif()
+
 set(SDL_X11_XRANDR_DEFAULT ON)
 if(SOLARIS)
   set(SDL_X11_XRANDR_DEFAULT OFF)
@@ -412,7 +421,7 @@ set_option(SDL2_DISABLE_UNINSTALL  "Disable uninstallation of SDL2" OFF)
 option_string(SDL_ASSERTIONS "Enable internal sanity checks (auto/disabled/release/enabled/paranoid)" "auto")
 #set_option(SDL_DEPENDENCY_TRACKING "Use gcc -MMD -MT dependency tracking" ON)
 set_option(SDL_ASSEMBLY            "Enable assembly routines" ${OPT_DEF_ASM})
-dep_option(SDL_SSEMATH             "Allow GCC to use SSE floating point math" ON "SDL_ASSEMBLY;SDL_CPU_X86 OR SDL_CPU_X64" OFF)
+dep_option(SDL_SSEMATH             "Allow GCC to use SSE floating point math" ON "SDL_ASSEMBLY;SDL_CPU_X86 OR SDL_CPU_X64;NOT DOS" OFF)
 dep_option(SDL_SSE                 "Use SSE assembly routines" ON "SDL_ASSEMBLY;SDL_CPU_X86 OR SDL_CPU_X64" OFF)
 dep_option(SDL_SSE2                "Use SSE2 assembly routines" ON "SDL_ASSEMBLY;SDL_CPU_X86 OR SDL_CPU_X64" OFF)
 dep_option(SDL_SSE3                "Use SSE3 assembly routines" ON "SDL_ASSEMBLY;SDL_CPU_X86 OR SDL_CPU_X64" OFF)
@@ -525,6 +534,10 @@ if(VITA)
   set_option(VIDEO_VITA_PVR  "Build with PSVita PVR gles/gles2 support" OFF)
 endif()
 
+if(DOS)
+  set_option(SDL_DOS_UCLOCK "Whether to use uclock() for performance counter on DOS" TRUE)
+endif()
+
 # General source files
 file(GLOB SOURCE_FILES
   ${SDL2_SOURCE_DIR}/src/*.c
@@ -2873,6 +2886,28 @@ elseif(OS2)
     CheckHIDAPI()
   endif()
 
+elseif(DOS)
+  file(GLOB DOS_CORE_SOURCES ${SDL2_SOURCE_DIR}/src/core/dos/*.c)
+  list(APPEND SOURCE_FILES ${DOS_CORE_SOURCES})
+
+  if(SDL_TIMERS)
+    if(SDL_DOS_UCLOCK)
+      set(HAVE_UCLOCK TRUE)
+    endif()
+
+    set(SDL_TIMER_DOS 1)
+    file(GLOB DOS_TIMER_SOURCES ${SDL2_SOURCE_DIR}/src/timer/dos/*.c)
+    list(APPEND SOURCE_FILES ${DOS_TIMER_SOURCES})
+    set(HAVE_SDL_TIMERS TRUE)
+  endif()
+
+  if(SDL_VIDEO)
+    set(SDL_VIDEO_DRIVER_SVGA 1)
+    file(GLOB SVGA_VIDEO_SOURCES ${SDL2_SOURCE_DIR}/src/video/svga/*.c)
+    list(APPEND SOURCE_FILES ${SVGA_VIDEO_SOURCES})
+    set(HAVE_SDL_VIDEO TRUE)
+  endif()
+
 elseif(N3DS)
   file(GLOB N3DS_MAIN_SOURCES ${SDL2_SOURCE_DIR}/src/main/n3ds/*.c)
   set(SDLMAIN_SOURCES ${SDLMAIN_SOURCES} ${N3DS_MAIN_SOURCES})
@@ -3028,7 +3063,7 @@ endif()
 # We always need to have threads and timers around
 if(NOT HAVE_SDL_THREADS)
   # The emscripten platform has been carefully vetted to work without threads
-  if (EMSCRIPTEN)
+  if (EMSCRIPTEN OR DOS)
     set(SDL_THREADS_DISABLED 1)
     file(GLOB THREADS_SOURCES ${SDL2_SOURCE_DIR}/src/thread/generic/*.c)
     list(APPEND SOURCE_FILES ${THREADS_SOURCES})

configure

@@ -952,6 +952,7 @@ enable_wasapi
 enable_hidapi_joystick
 enable_hidapi_libusb
 enable_clock_gettime
+enable_uclock
 enable_rpath
 enable_backgrounding_signal
 enable_foregrounding_signal
@@ -1671,9 +1672,9 @@ Optional Features:
   --enable-assembly       Enable assembly routines [default=yes]
   --enable-ssemath        Allow GCC to use SSE floating point math
                           [default=maybe]
-  --enable-mmx            use MMX assembly routines [default=yes]
-  --enable-3dnow          use 3DNow! assembly routines [default=no]
-  --enable-sse            use SSE assembly routines [default=yes]
+  --enable-mmx            use MMX assembly routines [default=maybe]
+  --enable-3dnow          use 3DNow! assembly routines [default=maybe]
+  --enable-sse            use SSE assembly routines [default=maybe]
   --enable-sse2           use SSE2 assembly routines [default=maybe]
   --enable-sse3           use SSE3 assembly routines [default=maybe]
   --enable-altivec        use Altivec assembly routines [default=yes]
@@ -1779,6 +1780,8 @@ Optional Features:
   --enable-clock_gettime  use clock_gettime() instead of gettimeofday() on
                           UNIX [default=yes]
   --enable-rpath          use an rpath when linking SDL [default=yes]
+  --enable-uclock         use uclock() for performance counter on DOS
+                          [default=yes]
   --enable-backgrounding-signal
                           number to use for magic backgrounding signal or 'no'
                           [default=no]
@@ -19358,6 +19361,25 @@ printf "%s\n" "#define HAVE_MPROTECT 1" >>confdefs.h
 
 fi
 rm -f core conftest.err conftest.$ac_objext conftest.beam conftest.$ac_ext
+    case "$host" in
+    *-*-msdosdjgpp*)
+        { $as_echo "$as_me:${as_lineno-$LINENO}: skipping unfinished fseeko64 in DJGPP" >&5
+$as_echo "$as_me: skipping unfinished fseeko64 in DJGPP" >&6;}
+        ;;
+    *)
+        for ac_func in fseeko64
+do :
+  ac_fn_c_check_func "$LINENO" "fseeko64" "ac_cv_func_fseeko64"
+if test "x$ac_cv_func_fseeko64" = xyes; then :
+  cat >>confdefs.h <<_ACEOF
+#define HAVE_FSEEKO64 1
+_ACEOF
+
+fi
+done
+
+        ;;
+    esac
 fi
 
     ac_fn_c_check_func "$LINENO" "malloc" "ac_cv_func_malloc"
@@ -19743,12 +19765,6 @@ if test "x$ac_cv_func_fseeko" = xyes
 then :
   printf "%s\n" "#define HAVE_FSEEKO 1" >>confdefs.h
 
-fi
-ac_fn_c_check_func "$LINENO" "fseeko64" "ac_cv_func_fseeko64"
-if test "x$ac_cv_func_fseeko64" = xyes
-then :
-  printf "%s\n" "#define HAVE_FSEEKO64 1" >>confdefs.h
-
 fi
 ac_fn_c_check_func "$LINENO" "sigaction" "ac_cv_func_sigaction"
 if test "x$ac_cv_func_sigaction" = xyes
@@ -20647,7 +20663,7 @@ if test ${enable_mmx+y}
 then :
   enableval=$enable_mmx;
 else $as_nop
-  enable_mmx=yes
+  enable_mmx=$default_ssemath
 fi
 
     if test x$enable_mmx = xyes; then
@@ -20703,7 +20719,7 @@ if test ${enable_3dnow+y}
 then :
   enableval=$enable_3dnow;
 else $as_nop
-  enable_3dnow=no
+  enable_3dnow=$default_ssemath
 fi
 
     if test x$enable_3dnow = xyes; then
@@ -20754,7 +20770,7 @@ if test ${enable_sse+y}
 then :
   enableval=$enable_sse;
 else $as_nop
-  enable_sse=yes
+  enable_sse=$default_ssemath
 fi
 
     if test x$enable_sse = xyes; then
@@ -25984,6 +26000,18 @@ printf "%s\n" "#define SDL_AUDIO_DRIVER_QSA 1" >>confdefs.h
     fi
 }
 
+CheckSVGAVideo()
+{
+    if test x$enable_video = xyes; then
+
+$as_echo "#define SDL_VIDEO_DRIVER_SVGA 1" >>confdefs.h
+
+        SOURCES="$SOURCES $srcdir/src/video/svga/*.c"
+        have_video=yes
+        SUMMARY_video="${SUMMARY_video} svga"
+    fi
+}
+
 # Check whether --enable-video-opengl was given.
 if test ${enable_video_opengl+y}
 then :
@@ -28553,6 +28581,30 @@ printf "%s\n" "#define HAVE_CLOCK_GETTIME 1" >>confdefs.h
     fi
 }
 
+CheckUCLOCK()
+{
+    # Check whether --enable-uclock was given.
+if test "${enable_uclock+set}" = set; then :
+  enableval=$enable_uclock;
+else
+  enable_uclock=yes
+fi
+
+    if test x$enable_uclock = xyes; then
+        for ac_func in uclock
+do :
+  ac_fn_c_check_func "$LINENO" "uclock" "ac_cv_func_uclock"
+if test "x$ac_cv_func_uclock" = xyes; then :
+  cat >>confdefs.h <<_ACEOF
+#define HAVE_UCLOCK 1
+_ACEOF
+
+fi
+done
+
+    fi
+}
+
 CheckLinuxVersion()
 {
     ac_fn_c_check_header_compile "$LINENO" "linux/version.h" "ac_cv_header_linux_version_h" "$ac_includes_default"
@@ -29762,6 +29814,29 @@ printf "%s\n" "#define SDL_JOYSTICK_OS2 1" >>confdefs.h
             have_joystick=yes
         fi
         ;;
+    *-*-msdosdjgpp*)
+        ARCH=dos
+        CheckVisibilityHidden
+        CheckDeclarationAfterStatement
+        CheckDummyVideo
+        CheckDiskAudio
+        CheckDummyAudio
+        CheckSVGAVideo
+        CheckDLOPEN
+        CheckUCLOCK
+
+        # Set up files for the timer library
+        if test x$enable_timers = xyes; then
+
+$as_echo "#define SDL_TIMER_DOS 1" >>confdefs.h
+
+            SOURCES="$SOURCES $srcdir/src/timer/dos/*.c"
+            have_timers=yes
+        fi
+
+        # Set up files for shared DOS utilities and event handling
+        SOURCES="$SOURCES $srcdir/src/core/dos/*.c"
+        ;;
     *)
         as_fn_error $? "
 *** Unsupported host:  Please add to configure.ac

configure.ac

@@ -359,7 +359,17 @@ dnl Checks for library functions.
         AC_DEFINE(HAVE_MPROTECT, 1, [ ])
         ],[]),
     )
-    AC_CHECK_FUNCS(malloc calloc realloc free getenv setenv putenv unsetenv bsearch qsort abs bcopy memset memcmp memcpy memmove wcslen wcslcpy wcslcat _wcsdup wcsdup wcsstr wcscmp wcsncmp wcscasecmp _wcsicmp wcsncasecmp _wcsnicmp strlen strlcpy strlcat _strrev _strupr _strlwr index rindex strchr strrchr strstr strtok_r itoa _ltoa _uitoa _ultoa strtod strtol strtoul _i64toa _ui64toa strtoll strtoull atoi atof strcmp strncmp _stricmp strcasecmp _strnicmp strncasecmp strcasestr vsscanf vsnprintf fopen64 fseeko fseeko64 sigaction sigtimedwait setjmp nanosleep sysconf sysctlbyname getauxval elf_aux_info poll memfd_create posix_fallocate _Exit)
+
+    case "$host" in
+    *-*-msdosdjgpp*)
+        AC_MSG_NOTICE(skipping unfinished fseeko64 in DJGPP)
+        ;;
+    *)
+        AC_CHECK_FUNCS(fseeko64)
+        ;;
+    esac
+
+    AC_CHECK_FUNCS(malloc calloc realloc free getenv setenv putenv unsetenv bsearch qsort abs bcopy memset memcmp memcpy memmove wcslen wcslcpy wcslcat _wcsdup wcsdup wcsstr wcscmp wcsncmp wcscasecmp _wcsicmp wcsncasecmp _wcsnicmp strlen strlcpy strlcat _strrev _strupr _strlwr index rindex strchr strrchr strstr strtok_r itoa _ltoa _uitoa _ultoa strtod strtol strtoul _i64toa _ui64toa strtoll strtoull atoi atof strcmp strncmp _stricmp strcasecmp _strnicmp strncasecmp strcasestr vsscanf vsnprintf fopen64 fseeko sigaction sigtimedwait setjmp nanosleep sysconf sysctlbyname getauxval elf_aux_info poll memfd_create posix_fallocate _Exit)
 
     AC_CHECK_LIB(m, pow, [LIBS="$LIBS -lm"; EXTRA_LDFLAGS="$EXTRA_LDFLAGS -lm"])
     AC_CHECK_FUNCS(acos acosf asin asinf atan atanf atan2 atan2f ceil ceilf copysign copysignf cos cosf exp expf fabs fabsf floor floorf trunc truncf fmod fmodf log logf log10 log10f lround lroundf pow powf round roundf scalbn scalbnf sin sinf sqrt sqrtf tan tanf)
@@ -664,8 +674,8 @@ if test x$enable_assembly = xyes; then
 
 dnl Check for various instruction support
     AC_ARG_ENABLE(mmx,
-[AS_HELP_STRING([--enable-mmx], [use MMX assembly routines [default=yes]])],
-                  , enable_mmx=yes)
+[AS_HELP_STRING([--enable-mmx], [use MMX assembly routines [[default=maybe]]])],
+                  , enable_mmx=$default_ssemath)
     if test x$enable_mmx = xyes; then
         save_CFLAGS="$CFLAGS"
         have_gcc_mmx=no
@@ -698,8 +708,8 @@ dnl Check for various instruction support
     fi
 
     AC_ARG_ENABLE(3dnow,
-[AS_HELP_STRING([--enable-3dnow], [use 3DNow! assembly routines [default=no]])],
-                  , enable_3dnow=no)
+[AS_HELP_STRING([--enable-3dnow], [use 3DNow! assembly routines [[default=maybe]]])],
+                  , enable_3dnow=$default_ssemath)
     if test x$enable_3dnow = xyes; then
         save_CFLAGS="$CFLAGS"
         have_gcc_3dnow=no
@@ -727,8 +737,8 @@ dnl Check for various instruction support
     fi
 
     AC_ARG_ENABLE(sse,
-[AS_HELP_STRING([--enable-sse], [use SSE assembly routines [default=yes]])],
-                  , enable_sse=yes)
+[AS_HELP_STRING([--enable-sse], [use SSE assembly routines [[default=maybe]]])],
+                  , enable_sse=$default_ssemath)
     if test x$enable_sse = xyes; then
         save_CFLAGS="$CFLAGS"
         have_gcc_sse=no
@@ -2508,6 +2518,17 @@ CheckQNXAudio()
     fi
 }
 
+dnl Set up the SVGA video driver if enabled
+CheckSVGAVideo()
+{
+    if test x$enable_video = xyes; then
+        AC_DEFINE(SDL_VIDEO_DRIVER_SVGA, 1, [ ])
+        SOURCES="$SOURCES $srcdir/src/video/svga/*.c"
+        have_video=yes
+        SUMMARY_video="${SUMMARY_video} svga"
+    fi
+}
+
 dnl Check to see if OpenGL support is desired
 AC_ARG_ENABLE(video-opengl,
 [AS_HELP_STRING([--enable-video-opengl], [include OpenGL support [default=yes]])],
@@ -3694,6 +3715,17 @@ CheckClockGettime()
     fi
 }
 
+dnl Check for uclock()
+CheckUCLOCK()
+{
+    AC_ARG_ENABLE(uclock,
+AS_HELP_STRING([--enable-uclock], [use uclock() for performance counter on DOS [[default=yes]]]),
+                  , enable_uclock=yes)
+    if test x$enable_uclock = xyes; then
+        AC_CHECK_FUNCS(uclock)
+    fi
+}
+
 dnl Check for a valid linux/version.h
 CheckLinuxVersion()
 {
@@ -4673,6 +4705,27 @@ dnl BeOS support removed after SDL 2.0.1. Haiku still works.  --ryan.
             have_joystick=yes
         fi
         ;;
+    *-*-msdosdjgpp*)
+        ARCH=dos
+        CheckVisibilityHidden
+        CheckDeclarationAfterStatement
+        CheckDummyVideo
+        CheckDiskAudio
+        CheckDummyAudio
+        CheckSVGAVideo
+        CheckDLOPEN
+        CheckUCLOCK
+
+        # Set up files for the timer library
+        if test x$enable_timers = xyes; then
+            AC_DEFINE(SDL_TIMER_DOS, 1, [ ])
+            SOURCES="$SOURCES $srcdir/src/timer/dos/*.c"
+            have_timers=yes
+        fi
+
+        # Set up files for shared DOS utilities and event handling
+        SOURCES="$SOURCES $srcdir/src/core/dos/*.c"
+        ;;
     *)
         AC_MSG_ERROR([
 *** Unsupported host:  Please add to configure.ac