Make ScummVM run in usermode, install exception handler in kernelmode.

svn-id: r18897

1 files changed, 23 insertions, 5 deletions

diff --git a/backends/psp/psp_main.cpp b/backends/psp/psp_main.cpp
index 0a4b8fa05d..89ad768941 100644
--- a/backends/psp/psp_main.cpp
+++ b/backends/psp/psp_main.cpp
@@ -37,10 +37,21 @@
 #include <pspgu.h>
 #include "./trace.h"
 
+
+/**
+ * Define the module info section
+ *
+ * 2nd arg must 0x1000 so __init is executed in
+ * kernelmode for our loaderInit function
+ */
 PSP_MODULE_INFO("SCUMMVM-PSP", 0x1000, 1, 1);
 
-/* Define the main thread's attribute value (optional) */
-PSP_MAIN_THREAD_ATTR(/*THREAD_ATTR_USER | THREAD_ATTR_VFPU*/ 0);
+/**
+ * THREAD_ATTR_USER causes the thread that the startup
+ * code (crt0.c) starts this program in to be in usermode
+ * even though the module was started in kernelmode
+ */
+PSP_MAIN_THREAD_ATTR(THREAD_ATTR_USER | THREAD_ATTR_VFPU);
 
 /* global quit flag, this is used to let the VM engine shutdown properly */
 bool g_quit = false;
@@ -60,6 +71,16 @@ void MyExceptionHandler(PspDebugRegBlock *regs) {
 	while (1) ;
 }
 
+/**
+ * Function that is called from _init in kernelmode before the
+ * main thread is started in usermode.
+ */
+__attribute__ ((constructor))
+void loaderInit() {
+	pspKernelSetKernelPC();
+	pspDebugInstallErrorHandler(MyExceptionHandler);
+}
+
 
 /* Exit callback */
 SceKernelCallbackFunction exit_callback(int /*arg1*/, int /*arg2*/, void * /*common*/) {
@@ -104,9 +125,6 @@ int main(void)
 	//PSPDebugTrace("Setup callbacks\n");
 	SetupCallbacks();
 
-	//install exception handler
-	pspDebugInstallErrorHandler(MyExceptionHandler);
-
 	//check if the save directory exists
 	SceUID fd = sceIoDopen(SCUMMVM_SAVEPATH);
 	if (fd < 0) {