optimization: do not start/link timer functions if system time never gets called

Author: uyjulian

ee/kernel/Makefile

@@ -125,6 +125,8 @@ EXIT_OBJS += _exit_internals.o SetArg.o Exit.o ExecPS2.o LoadExecPS2.o ExecOSD.o
 
 TIMER_OBJS = \
 	timer_data.o \
+	_ps2sdk_init_timer.o \
+	_ps2sdk_deinit_timer.o \
 	SetT2.o \
 	SetT2_COUNT.o \
 	SetT2_MODE.o \

ee/kernel/include/kernel.h

@@ -575,10 +575,8 @@ extern void *GetEntryAddress(int syscall);
     void ExecOSD(int num_args, char *args[]) { _ExecOSD(num_args, args); }
 
 #define DISABLE_TimerSystemTime() \
-    s32 InitTimer(s32 in_mode) {(void)in_mode; return 0;} \
-    s32 EndTimer(void) {return 0;} \
-    s32 StartTimerSystemTime(void) {return 0;} \
-    s32 StopTimerSystemTime(void) {return 0;}
+    void _ps2sdk_init_timer() {} \
+    void _ps2sdk_deinit_timer() {}
 
 #define DISABLE_TimerAlarm() \
     void ForTimer_InitAlarm(void) {}

ee/kernel/include/timer.h

@@ -66,6 +66,11 @@ typedef u64 (*timer_alarm_handler_t)(s32 id, u64 scheduled_time, u64 actual_time
 extern "C" {
 #endif
 
+extern void _ps2sdk_init_timer_impl(void);
+extern void _ps2sdk_init_timer(void);
+extern void _ps2sdk_deinit_timer_impl(void);
+extern void _ps2sdk_deinit_timer(void);
+
 extern s32 InitTimer(s32 in_mode);
 extern s32 EndTimer(void);
 extern s32 GetTimerPreScaleFactor(void);

ee/kernel/src/initsys.c

@@ -21,8 +21,7 @@
 void _InitSys(void)
 {
     InitAlarm();
-    InitTimer(2);
-    StartTimerSystemTime();
+    _ps2sdk_init_timer();
     InitThread();
     InitExecPS2();
     InitTLBFunctions();
@@ -32,8 +31,7 @@ void _InitSys(void)
 #ifdef F_TerminateLibrary
 void TerminateLibrary(void)
 {
-    StopTimerSystemTime();
-    EndTimer();
+    _ps2sdk_deinit_timer();
     InitTLB();
 }
 #endif

ee/kernel/src/timer.c

@@ -79,6 +79,30 @@ extern timer_ee_global_struct g_Timer;
 extern counter_struct_t g_CounterBuf[COUNTER_COUNT] __attribute__((aligned(64)));
 #endif
 
+#ifdef F__ps2sdk_init_timer
+void __attribute__((weak)) _ps2sdk_init_timer_impl(void);
+__attribute__((weak)) void _ps2sdk_init_timer(void)
+{
+    // cppcheck-suppress knownConditionTrueFalse
+    if (&_ps2sdk_init_timer_impl)
+    {
+        _ps2sdk_init_timer_impl();
+    }
+}
+#endif
+
+#ifdef F__ps2sdk_deinit_timer
+void __attribute__((weak)) _ps2sdk_deinit_timer_impl(void);
+__attribute__((weak)) void _ps2sdk_deinit_timer(void)
+{
+    // cppcheck-suppress knownConditionTrueFalse
+    if (&_ps2sdk_deinit_timer_impl)
+    {
+        _ps2sdk_deinit_timer_impl();
+    }
+}
+#endif
+
 #ifdef F_SetT2
 void SetT2(volatile void *ptr, u32 val)
 {
@@ -478,6 +502,18 @@ u64 iGetTimerSystemTime(void)
     timer_system_time_now = timer_system_time_now << ((mode & 3) << 2);
     return timer_system_time_now;
 }
+
+void _ps2sdk_init_timer_impl(void)
+{
+    InitTimer(2);
+    StartTimerSystemTime();
+}
+
+void _ps2sdk_deinit_timer_impl(void)
+{
+    StopTimerSystemTime();
+    EndTimer();
+}
 #endif
 
 #ifdef F_GetTimerSystemTime