--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/gpf/osl/os_sem_ir.c	Sun Jul 15 08:15:49 2018 +0000
@@ -0,0 +1,91 @@
+/*
+ * This C module is a reconstruction based on the disassembly of
+ * os_sem.obj in frame_na7_db_ir.lib from the Leonardo package.
+ */
+
+/* set of included headers from COFF symtab: */
+#include <stdio.h>
+#include <string.h>
+#include "nucleus.h"
+#include "typedefs.h"
+#include "os.h"
+#include "gdi.h"
+#include "os_types.h"
+#include "os_glob.h"
+
+extern T_OS_SEM_TABLE_ENTRY SemTable[];
+extern unsigned os_time_to_tick_multiplier;
+
+int
+ReleaseSemaphoreCB(NU_SEMAPHORE *SemCB)
+{
+	if (NU_Release_Semaphore(SemCB) == NU_SUCCESS)
+		return(OS_OK);
+	else
+		return(OS_ERROR);
+}
+
+GLOBAL LONG
+os_ReleaseSemaphore(OS_HANDLE TaskHandle, OS_HANDLE SemHandle)
+{
+	if (NU_Release_Semaphore(&SemTable[SemHandle].SemCB) == NU_SUCCESS)
+		return(OS_OK);
+	else
+		return(OS_ERROR);
+}
+
+int
+ObtainSemaphoreCB(NU_SEMAPHORE *SemCB, ULONG Timeout, USHORT wait_check)
+{
+	UNSIGNED nu_timeout;
+	STATUS sts;
+	int ret;
+
+	ret = OS_OK;
+	if (Timeout != OS_SUSPEND)
+		nu_timeout = TIME_TO_SYSTEM_TICKS(Timeout);
+	else if (wait_check == 1)
+		nu_timeout = 1;
+	else
+		nu_timeout = NU_SUSPEND;
+	for (;;) {
+		sts = NU_Obtain_Semaphore(SemCB, nu_timeout);
+		switch (sts) {
+		case NU_SUCCESS:
+			return(ret);
+		case NU_INVALID_SEMAPHORE:
+			return(OS_ERROR);
+		case NU_INVALID_SUSPEND:
+			nu_timeout = 0;
+			continue;
+		case NU_TIMEOUT:
+		case NU_UNAVAILABLE:
+			if (nu_timeout == 1 && wait_check == 1) {
+				nu_timeout = NU_SUSPEND;
+				ret = OS_WAITED;
+				continue;
+			}
+			return(OS_TIMEOUT);
+		default:
+			/*
+			 * Disassembly reveals that the original code
+			 * has an endless loop here, the equivalent
+			 * of continue.  My guess is that they simply
+			 * forgot the default case, and so control
+			 * falls onto the closing brace of the switch
+			 * and then onto the closing brace of the for
+			 * loop.  But I prefer better error handling,
+			 * hence the present addition. - Space Falcon
+			 */
+			return(OS_ERROR);
+		}
+	}
+}
+
+GLOBAL LONG
+os_ObtainSemaphore(OS_HANDLE TaskHandle, OS_HANDLE SemHandle, ULONG Timeout)
+{
+	if (SemHandle > MaxSemaphores)
+		return(OS_ERROR);
+	return ObtainSemaphoreCB(&SemTable[SemHandle].SemCB, Timeout, 0);
+}