rtc: add an rtc_ticks() function similar to RTC_GetTicks()

CMakeLists.txt

@@ -41,6 +41,7 @@ set(SOURCES_COMMON
   src/render/topti.c
   src/rtc/inth.s
   src/rtc/rtc.c
+  src/rtc/rtc_ticks.c
   src/spu/spu.c
   src/std/tinymt32/rand.c
   src/std/tinymt32/tinymt32.c

include/gint/rtc.h

@@ -22,6 +22,7 @@ typedef struct
 	uint8_t hours;		/* Hour (0..23) */
 	uint8_t minutes;	/* Minute (0..59) */
 	uint8_t seconds;	/* Second (0..59) */
+	uint8_t ticks;		/* 128-Hz sub-second counter (0...127) */
 
 } rtc_time_t;
 
@@ -31,10 +32,16 @@ void rtc_get_time(rtc_time_t *time);
 
 /* rtc_set_time(): Set current time in the RTC
    If [time->week_day] is not in the valid range, it is set to 0. Other fields
-   are not checked.
+   are not checked. R64CNT cannot be set to [time->ticks] is ignored.
    @time  Pointer to new time */
 void rtc_set_time(rtc_time_t const *time);
 
+/* rtc_ticks(): Get number of 128-Hz ticks elapsed since Midnight.
+
+   Returns R64CNT + 128*RSECCNT + 128*60*RMINCNT + 128*60*60*RHRCNT. This can
+   be used as a 128-Hz counter, but it wraps around at midnight. */
+uint32_t rtc_ticks(void);
+
 //---
 //	RTC timer
 //	The real-time clock produces a regular interrupt which may be used as a

src/rtc/rtc.c

@@ -61,6 +61,7 @@ void rtc_get_time(rtc_time_t *time)
 	do {
 		RTC->RCR1.CF = 0;
 
+		time->ticks     = RTC->R64CNT;
 		time->seconds   = int8(RTC->RSECCNT.byte);
 		time->minutes   = int8(RTC->RMINCNT.byte);
 		time->hours     = int8(RTC->RHRCNT.byte);

src/rtc/rtc_ticks.c

@@ -0,0 +1,14 @@
+#include <gint/rtc.h>
+
+uint32_t rtc_ticks(void)
+{
+	rtc_time_t t;
+	rtc_get_time(&t);
+
+	uint32_t ticks = t.hours;
+	ticks =  60 * ticks + t.minutes;
+	ticks =  60 * ticks + t.seconds;
+	ticks = 128 * ticks + t.ticks;
+
+	return ticks;
+}