Add basic support for compiling on RISC OS

CMakeLists.txt

@@ -129,7 +129,7 @@ elseif(CMAKE_SYSTEM_NAME MATCHES "Haiku.*")
 endif()
 
 # Don't mistake osx for unix
-if(UNIX AND NOT APPLE)
+if(UNIX AND NOT APPLE AND NOT RISCOS)
   set(UNIX_SYS ON)
 else()
   set(UNIX_SYS OFF)
@@ -341,7 +341,7 @@ set_option(VIDEO_OPENGLES      "Include OpenGL ES support" ON)
 set_option(PTHREADS            "Use POSIX threads for multi-threading" ${SDL_PTHREADS_ENABLED_BY_DEFAULT})
 dep_option(PTHREADS_SEM        "Use pthread semaphores" ON "PTHREADS" OFF)
 set_option(SDL_DLOPEN          "Use dlopen for shared object loading" ${SDL_DLOPEN_ENABLED_BY_DEFAULT})
-set_option(OSS                 "Support the OSS audio API" ${UNIX_SYS})
+dep_option(OSS                 "Support the OSS audio API" ON "UNIX_SYS OR RISCOS" OFF)
 set_option(ALSA                "Support the ALSA audio API" ${UNIX_SYS})
 dep_option(ALSA_SHARED         "Dynamically load ALSA audio support" ON "ALSA" OFF)
 set_option(JACK                "Support the JACK audio API" ${UNIX_SYS})
@@ -1091,7 +1091,7 @@ elseif(EMSCRIPTEN)
     endif()
   endif()
 
-elseif(UNIX AND NOT APPLE AND NOT ANDROID)
+elseif(UNIX AND NOT APPLE AND NOT ANDROID AND NOT RISCOS)
   if(SDL_AUDIO)
     if(SYSV5 OR SOLARIS OR HPUX)
         set(SDL_AUDIO_DRIVER_SUNAUDIO 1)
@@ -1814,6 +1814,24 @@ elseif(HAIKU)
   endif()
 
   CheckPTHREAD()
+
+elseif(RISCOS)
+  if(SDL_TIMERS)
+    set(SDL_TIMER_UNIX 1)
+    file(GLOB TIMER_SOURCES ${SDL2_SOURCE_DIR}/src/timer/unix/*.c)
+    set(SOURCE_FILES ${SOURCE_FILES} ${TIMER_SOURCES})
+    set(HAVE_SDL_TIMERS TRUE)
+
+    if(CLOCK_GETTIME)
+      set(HAVE_CLOCK_GETTIME 1)
+    endif()
+  endif()
+
+  CheckPTHREAD()
+
+  if(SDL_AUDIO)
+    CheckOSS()
+  endif()
 endif()
 
 if(VIDEO_VULKAN)

configure

@@ -25365,6 +25365,27 @@ $as_echo "#define SDL_FILESYSTEM_EMSCRIPTEN 1" >>confdefs.h
         # Set up files for the timer library
         if test x$enable_timers = xyes; then
 
+$as_echo "#define SDL_TIMER_UNIX 1" >>confdefs.h
+
+            SOURCES="$SOURCES $srcdir/src/timer/unix/*.c"
+            have_timers=yes
+        fi
+        ;;
+    *-*-riscos*)
+        ARCH=riscos
+        CheckVisibilityHidden
+        CheckDeclarationAfterStatement
+        CheckDummyVideo
+        CheckDiskAudio
+        CheckDummyAudio
+        CheckDLOPEN
+        CheckOSS
+        CheckPTHREAD
+        CheckClockGettime
+
+        # Set up files for the timer library
+        if test x$enable_timers = xyes; then
+
 $as_echo "#define SDL_TIMER_UNIX 1" >>confdefs.h
 
             SOURCES="$SOURCES $srcdir/src/timer/unix/*.c"

configure.ac

@@ -4056,6 +4056,25 @@ AS_HELP_STRING([--enable-render-d3d], [enable the Direct3D render driver [[defau
             SOURCES="$SOURCES $srcdir/src/filesystem/emscripten/*.c"
             have_filesystem=yes
         fi
+        # Set up files for the timer library
+        if test x$enable_timers = xyes; then
+            AC_DEFINE(SDL_TIMER_UNIX, 1, [ ])
+            SOURCES="$SOURCES $srcdir/src/timer/unix/*.c"
+            have_timers=yes
+        fi
+        ;;
+    *-*-riscos*)
+        ARCH=riscos
+        CheckVisibilityHidden
+        CheckDeclarationAfterStatement
+        CheckDummyVideo
+        CheckDiskAudio
+        CheckDummyAudio
+        CheckDLOPEN
+        CheckOSS
+        CheckPTHREAD
+        CheckClockGettime
+
         # Set up files for the timer library
         if test x$enable_timers = xyes; then
             AC_DEFINE(SDL_TIMER_UNIX, 1, [ ])

src/atomic/SDL_spinlock.c

@@ -32,6 +32,10 @@
 #include <atomic.h>
 #endif
 
+#if !defined(HAVE_GCC_ATOMICS) && defined(__RISCOS__)
+#include <unixlib/local.h>
+#endif
+
 #if defined(_MSC_VER) && (defined(_M_IX86) || defined(_M_X64))
 #include <xmmintrin.h>
 #endif
@@ -84,6 +88,16 @@ SDL_AtomicTryLock(SDL_SpinLock *lock)
          defined(__ARM_ARCH_5__) || defined(__ARM_ARCH_5TE__) || \
          defined(__ARM_ARCH_5TEJ__))
     int result;
+
+#if defined(__RISCOS__)
+    if (__cpucap_have_rex()) {
+        __asm__ __volatile__ (
+            "ldrex %0, [%2]\nteq   %0, #0\nstrexeq %0, %1, [%2]"
+            : "=&r" (result) : "r" (1), "r" (lock) : "cc", "memory");
+        return (result == 0);
+    }
+#endif
+
     __asm__ __volatile__ (
         "swp %0, %1, [%2]\n"
         : "=&r,&r" (result) : "r,0" (1), "r,r" (lock) : "memory");

src/dynapi/SDL_dynapi.h

@@ -53,6 +53,8 @@
 #define SDL_DYNAMIC_API 0
 #elif defined(__PSP__) && __PSP__
 #define SDL_DYNAMIC_API 0
+#elif defined(__riscos__) && __riscos__ /* probably not useful on RISC OS, since dlopen() can't be used when using static linking. */
+#define SDL_DYNAMIC_API 0
 #elif defined(__clang_analyzer__)
 #define SDL_DYNAMIC_API 0  /* Turn off for static analysis, so reports are more clear. */
 #endif

src/thread/pthread/SDL_systhread.c

@@ -188,7 +188,7 @@ SDL_ThreadID(void)
 int
 SDL_SYS_SetThreadPriority(SDL_ThreadPriority priority)
 {
-#if __NACL__ 
+#if __NACL__ || __RISCOS__
     /* FIXME: Setting thread priority does not seem to be supported in NACL */
     return 0;
 #elif __LINUX__

test/configure

@@ -2988,6 +2988,11 @@ fi
         MATHLIB=""
         SYS_GL_LIBS=""
         ;;
+    *-*-riscos* )
+        EXE=",e1f"
+        MATHLIB=""
+        SYS_GL_LIBS=""
+        ;;
     *)
                 ISUNIX="true"
         EXE=""

test/configure.ac

@@ -71,6 +71,11 @@ case "$host" in
         MATHLIB=""
         SYS_GL_LIBS=""
         ;;
+    *-*-riscos* )
+        EXE=",e1f"
+        MATHLIB=""
+        SYS_GL_LIBS=""
+        ;;
     *)
         dnl Oh well, call it Unix...
         ISUNIX="true"