+}
+
+
+#ifdef MSWIN32
+
+# ifdef __GNUC__
+
+ typedef struct {
+ EXCEPTION_REGISTRATION ex_reg;
+ void *alt_path;
+ } ext_ex_regn;
+
+
+ static EXCEPTION_DISPOSITION mark_ex_handler(
+ struct _EXCEPTION_RECORD *ex_rec,
+ void *est_frame,
+ struct _CONTEXT *context,
+ void *disp_ctxt)
+ {
+ if (ex_rec->ExceptionCode == STATUS_ACCESS_VIOLATION) {
+ ext_ex_regn *xer = (ext_ex_regn *)est_frame;
+
+ /* Unwind from the inner function assuming the standard */
+ /* function prologue. */
+ /* Assumes code has not been compiled with */
+ /* -fomit-frame-pointer. */
+ context->Esp = context->Ebp;
+ context->Ebp = *((DWORD *)context->Esp);
+ context->Esp = context->Esp - 8;
+
+ /* Resume execution at the "real" handler within the */
+ /* wrapper function. */
+ context->Eip = (DWORD )(xer->alt_path);
+
+ return ExceptionContinueExecution;
+
+ } else {
+ return ExceptionContinueSearch;
+ }
+ }
+# endif /* __GNUC__ */
+
+
+ GC_bool GC_mark_some(cold_gc_frame)
+ ptr_t cold_gc_frame;
+ {
+ GC_bool ret_val;
+
+# ifndef __GNUC__
+ /* Windows 98 appears to asynchronously create and remove */
+ /* writable memory mappings, for reasons we haven't yet */
+ /* understood. Since we look for writable regions to */
+ /* determine the root set, we may try to mark from an */
+ /* address range that disappeared since we started the */
+ /* collection. Thus we have to recover from faults here. */
+ /* This code does not appear to be necessary for Windows */
+ /* 95/NT/2000. Note that this code should never generate */
+ /* an incremental GC write fault. */
+
+ __try {
+
+# else /* __GNUC__ */
+
+ /* Manually install an exception handler since GCC does */
+ /* not yet support Structured Exception Handling (SEH) on */
+ /* Win32. */
+
+ ext_ex_regn er;
+
+ er.alt_path = &&handle_ex;
+ er.ex_reg.handler = mark_ex_handler;
+ asm volatile ("movl %%fs:0, %0" : "=r" (er.ex_reg.prev));
+ asm volatile ("movl %0, %%fs:0" : : "r" (&er));
+
+# endif /* __GNUC__ */
+
+ ret_val = GC_mark_some_inner(cold_gc_frame);
+
+# ifndef __GNUC__
+
+ } __except (GetExceptionCode() == EXCEPTION_ACCESS_VIOLATION ?
+ EXCEPTION_EXECUTE_HANDLER : EXCEPTION_CONTINUE_SEARCH) {
+
+# else /* __GNUC__ */
+
+ /* Prevent GCC from considering the following code unreachable */
+ /* and thus eliminating it. */
+ if (er.alt_path != 0)
+ goto rm_handler;
+
+handle_ex:
+ /* Execution resumes from here on an access violation. */
+
+# endif /* __GNUC__ */
+
+# ifdef CONDPRINT
+ if (GC_print_stats) {
+ GC_printf0("Caught ACCESS_VIOLATION in marker. "
+ "Memory mapping disappeared.\n");
+ }
+# endif /* CONDPRINT */
+
+ /* We have bad roots on the stack. Discard mark stack. */
+ /* Rescan from marked objects. Redetermine roots. */
+ GC_invalidate_mark_state();
+ scan_ptr = 0;
+
+ ret_val = FALSE;
+
+# ifndef __GNUC__
+