--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/gpf/osl/os_tim_fl.c	Fri Oct 16 06:23:26 2020 +0000
@@ -0,0 +1,184 @@
+/*
+ * This C module is a reconstruction based on the disassembly of
+ * os_tim.obj in frame_na7_db_fl.lib from the Leonardo package,
+ * subsequently reworked by Space Falcon.
+ */
+
+/* set of included headers from COFF symtab: */
+#include <stdio.h>
+#include "nucleus.h"
+#include "typedefs.h"
+#include "os.h"
+#include "gdi.h"
+#include "os_types.h"
+#include "os_glob.h"
+
+extern UNSIGNED TMD_Timer;
+extern INT      TMD_Timer_State;
+
+extern T_OS_TIMER_ENTRY TimerTable[];
+extern T_OS_TIMER_TABLE_ENTRY *p_list[];
+
+extern void os_Timeout(UNSIGNED t_handle);
+extern void timer_error(int err);
+
+unsigned os_time_to_tick_multiplier = TIME_TO_TICK_TDMA_FRAME_MULTIPLIER;
+unsigned os_tick_to_time_multiplier = TICK_TO_TIME_TDMA_FRAME_MULTIPLIER;
+
+unsigned volatile t_start_ticks;
+T_OS_TIMER_TABLE_ENTRY *t_running;
+int used_timers;
+int next_t_handle;
+int volatile t_list_access;
+int max_used_timers;
+NU_SEMAPHORE TimSemCB;
+NU_TIMER os_timer_cb;
+
+#ifdef __GNUC__
+#define	BARRIER	asm volatile ("": : :"memory")
+#else
+#define	BARRIER	/* prayer */
+#endif
+
+GLOBAL LONG
+os_set_tick(int os_system_tick)
+{
+	switch (os_system_tick) {
+	case SYSTEM_TICK_TDMA_FRAME:
+		os_time_to_tick_multiplier = TIME_TO_TICK_TDMA_FRAME_MULTIPLIER;
+		os_tick_to_time_multiplier = TICK_TO_TIME_TDMA_FRAME_MULTIPLIER;
+		return(OS_OK);
+	case SYSTEM_TICK_10_MS:
+		os_time_to_tick_multiplier = TIME_TO_TICK_10MS_MULTIPLIER;
+		os_tick_to_time_multiplier = TICK_TO_TIME_10MS_MULTIPLIER;
+		return(OS_OK);
+	default:
+		return(OS_ERROR);
+	}
+}
+
+GLOBAL LONG
+os_TimerInformation(USHORT Index, char *Buffer)
+{
+	static int t_info_read;
+
+	if (t_info_read) {
+		t_info_read = 0;
+		return(OS_ERROR);
+	}
+	sprintf(Buffer, "Maximum %d of %d available timers running",
+		max_used_timers, MaxSimultaneousTimer);
+	t_info_read = 1;
+	return(OS_OK);
+}
+
+GLOBAL LONG
+os_TimInit(void)
+{
+	int i;
+
+	if (NU_Create_Semaphore(&TimSemCB, "TIMSEM", 1, NU_PRIORITY)
+			!= NU_SUCCESS)
+		return(OS_ERROR);
+	if (NU_Create_Timer(&os_timer_cb, "OS_TIMER", os_Timeout, 0, 1, 0,
+			    NU_DISABLE_TIMER) != NU_SUCCESS)
+		return(OS_ERROR);
+	used_timers = 0;
+	max_used_timers = 0;
+	next_t_handle = 1;
+	t_list_access = 0;
+	t_start_ticks = 0;
+	p_list[0] = 0;
+	for (i = 1; i < MaxSimultaneousTimer; i++) {
+		TimerTable[i].entry.status = TMR_FREE;
+		TimerTable[i].entry.next = 0;
+		TimerTable[i].entry.prev = 0;
+		TimerTable[i].next_t_handle = i + 1;
+		p_list[i] = 0;
+	}
+	TimerTable[MaxSimultaneousTimer].entry.status = TMR_FREE;
+	TimerTable[MaxSimultaneousTimer].next_t_handle = 0;
+	t_running = 0;
+	return(OS_OK);
+}
+
+GLOBAL LONG
+os_RecoverTick(OS_TICK ticks)
+{
+	UNSIGNED current_system_clock;
+
+	current_system_clock = NU_Retrieve_Clock();
+	NU_Set_Clock(current_system_clock + ticks);
+	if (TMD_Timer_State == TM_ACTIVE) {
+		if (TMD_Timer <= ticks) {
+			TMD_Timer_State = TM_EXPIRED;
+			TMD_Timer = 0;
+		} else
+			TMD_Timer -= ticks;
+	}
+	return(OS_OK);
+}
+
+GLOBAL LONG
+os_QueryTimer(OS_HANDLE TaskHandle, OS_HANDLE TimerHandle,
+		OS_TIME *RemainingTime)
+{
+	T_OS_TIMER_TABLE_ENTRY *timer, *t_iter;
+	OS_TICK c_ticks, r_ticks, e_ticks;
+	STATUS sts;
+
+	if (TimerHandle > MaxSimultaneousTimer)
+		return(OS_ERROR);
+	sts = NU_Obtain_Semaphore(&TimSemCB, NU_SUSPEND);
+	timer = &TimerTable[TimerHandle].entry;
+	if (timer->status == TMR_FREE) {
+		if (sts == NU_SUCCESS)
+			NU_Release_Semaphore(&TimSemCB);
+		return(OS_ERROR);
+	}
+	t_list_access = 1;
+	BARRIER;
+	if (!t_running) {
+		r_ticks = 0;
+		goto out;
+	}
+	c_ticks = NU_Retrieve_Clock();
+	e_ticks = c_ticks - t_start_ticks;
+	t_iter = t_running;
+	if (t_iter->r_ticks >= e_ticks)
+		r_ticks = t_iter->r_ticks - e_ticks;
+	else
+		r_ticks = 0;
+	while (t_iter != timer) {
+		t_iter = t_iter->next;
+		if (t_iter == t_running) {
+			r_ticks = 0;
+			goto out;
+		}
+		r_ticks += t_iter->r_ticks;
+	}
+out:	BARRIER;
+	t_list_access = 0;
+	if (sts == NU_SUCCESS)
+		NU_Release_Semaphore(&TimSemCB);
+	*RemainingTime = SYSTEM_TICKS_TO_TIME(r_ticks);
+	return(OS_OK);
+}
+
+GLOBAL LONG
+os_InactivityTicks(int *next_event, OS_TICK *next_event_ticks)
+{
+	*next_event = 1;
+	switch (TMD_Timer_State) {
+	case TM_ACTIVE:
+		*next_event_ticks = TMD_Timer;
+		return(OS_OK);
+	case TM_NOT_ACTIVE:
+		*next_event_ticks = 0;
+		*next_event = 0;
+		return(OS_OK);
+	default:
+		*next_event_ticks = 0;
+		return(OS_OK);
+	}
+}