Redesigned timer module: got a possibly infinite amount of virtual timers.

Makefile

@@ -99,7 +99,7 @@ obj-std = $(foreach mod,$(modules-libc),$(mod-$(mod)-obj)) $(obj-std-spec)
 obj-lib	= $(foreach mod,$(modules-gint),$(mod-$(mod)-obj)) $(obj-lib-spec)
 
 # Dependencies.
-hdr-dep = $(wildcard include/*.h include/internals/*.h)
+hdr-dep = $(wildcard include/*.h include/*/*.h)
 
 
 
@@ -249,9 +249,9 @@ ifdef config_ext
 endif
 	@ printf '\e[32;1mmsg \u00bb\e[0m All installed!\n'
 
-install-demo:
+install-demo: all
 	p7 send -f $(target-g1a)
-install-debug:
+install-debug: all
 	p7 send -f $(target-dbg)
 
 .PHONY: all-lib all help

TODO

@@ -12,7 +12,8 @@ Simple improvements:
 -  string:	Use cmp/str to implement memchr() (assembler examples)
 -  string:	Do some tests for memcmp()
 -  core:	Register more interrupts (and understand their parameters)
--  rtc:		Take care of carry when reading time
+-  project:	Clean headers that have some internal definitions
+-  project:	Check size of all library structures
 Larger improvements:
 -  errno:	Introduce errno and use it more or less everywhere
 -  bopti:	Monochrome bitmaps blending modes
@@ -24,6 +25,7 @@ Larger improvements:
 -  usb:		Implement a driver
 -  esper:	Cleaner playback, synthetizing
 -  clock:	Handle overclocking (relaunch clocks when overclocking)
+-  project:	Unify this hellish mess of register access!
 
 Things to investigate:
 -  Packed bit fields alignment

configure

@@ -13,7 +13,7 @@ conf[GINT_EXTENDED_LIBC]=
 
 # Size limits
 conf[ATEXIT_MAX]=16
-conf[RTC_CB_ARRAY_SIZE]=5
+conf[TIMER_SLOTS]=16
 conf[EVENTS_QUEUE_SIZE]=64
 
 # Output files
@@ -50,8 +50,8 @@ Options that affect the behavior of the library:
 Options that customize size limits:
   $Cr--atexit-max$C0=$Cy<integer>$Cg [default:$Cp 16$Cg]$C0
     Number of exit handlers that can be registered by atexit().
-  $Cr--rtc-callbacks$C0=$Cy<integer>$Cg [default:$Cp 5$Cg]$C0
-    Number of RTC callbacks that can be registered.
+  $Cr--timer-slots$C0=$Cy<integer>$Cg [default:$Cp 16$Cg]$C0
+    Number of virtual timers that may be registered at the same time.
   $Cr--events-queue-size$C0=$Cy<integer>$Cg [default:$Cp 64$Cg]$C0
     Number of events simultaneously stored in the event queue.
 EOF
@@ -76,11 +76,11 @@ for arg; do case "$arg" in
 			conf[ATEXIT_MAX]=$size
 		else echo -e "$error --atexit-max expects an integer value"
 			fail=true; fi;;
-	--rtc-callbacks=*)
+	--timer-slots=*)
 		size=${arg#*=}
 		if [[ $size == +([0-9]) ]]; then
-			conf[RTC_CB_ARRAY_SIZE]=$size
-		else echo -e "$error --rtc-callbacks expects an integer value"
+			conf[TIMER_SLOTS]=$size
+		else echo -e "$error --timer-slots expects an integer value"
 			fail=true; fi;;
 	--events-queue-size=*)
 		size=${arg#*=}
@@ -90,7 +90,7 @@ for arg; do case "$arg" in
 			"value"
 			fail=true; fi;;
 
-	--atexit-max | --rtc-callbacks | --events-queue-size)
+	--atexit-max | --timer-slots | --events-queue-size)
 		echo -e "$error syntax for $arg is $arg=<integer-value>";;
 
 	*)
@@ -108,7 +108,7 @@ output_config_gcc()
 	[ "${conf[GINT_EXTENDED_LIBC]}" != "" ] && echo "-D GINT_EXTENDED_LIBC"
 
 	echo "-D ATEXIT_MAX=${conf[ATEXIT_MAX]}"
-	echo "-D RTC_CB_ARRAY_SIZE=${conf[RTC_CB_ARRAY_SIZE]}"
+	echo "-D TIMER_SLOTS=${conf[TIMER_SLOTS]}"
 	echo "-D EVENTS_QUEUE_SIZE=${conf[EVENTS_QUEUE_SIZE]}"
 }
 

demo/gintdemo.c

@@ -521,7 +521,6 @@ int main(void)
 	return 0;
 }
 
-/*
 void crash(void)
 {
 	__asm__(
@@ -530,4 +529,3 @@ void crash(void)
 		"trapa	#1		"
 	);
 }
-*/

demo/test_keyboard.c

@@ -102,7 +102,7 @@ static void draw_events(enhanced_event_t *history, int size)
 		"0",        ".",             "\x08", "(-)",  "EXE",   NULL
 	};
 	const char *event_names[] = {
-		"None ", "User ", "Press", "Rept.", "Rel. "
+		"None ", "User ", "Press", "Rept.", "Rel. ", "Timer"
 	};
 
 	for(int i = 0; i < size && history[i].type != ET_None; i++)

demo/test_rtc.c

@@ -16,7 +16,7 @@
 #include <internals/rtc.h>
 #include <mpu.h>
 
-static void draw(struct RTCTime time)
+static void draw(rtc_time_t time)
 {
 	extern Image res_rtc_segments;
 
@@ -53,8 +53,7 @@ static void draw(struct RTCTime time)
 static void callback(void)
 {
 	extern Image res_opt_rtc;
-	struct RTCTime time = rtc_getTime();
-	time.year += 1900;
+	rtc_time_t time = rtc_getTime();
 
 	dclear();
 	draw(time);
@@ -62,7 +61,7 @@ static void callback(void)
 	dupdate();
 }
 
-static void set_region(struct RTCTime *time, int region, int value)
+static void set_region(rtc_time_t *time, int region, int value)
 {
 	switch(region)
 	{
@@ -129,12 +128,10 @@ static void set(void)
 		{ 72, 39,  7,  9 }, {  84, 39,  7,  9 }, { 90, 39,  7,  9 },
 		{ 96, 39,  7,  9 }, { 102, 39,  7,  9 },
 	};
-	struct RTCTime time = rtc_getTime();
+	rtc_time_t time = rtc_getTime();
 	int region_count = 14;
 	int n = 0, slide = 0, key, leave;
 
-	time.year += 1900;
-
 	while(1)
 	{
 		dclear();
@@ -157,11 +154,9 @@ static void set(void)
 
 			else if(key == KEY_F1 || key == KEY_EXE)
 			{
-				n++;
 				slide = 0;
-				if(n == region_count)
+				if(++n == region_count)
 				{
-					time.year -= 1900;
 					rtc_setTime(time);
 					return;
 				}
@@ -187,7 +182,7 @@ static void set(void)
 
 				else if(n == 6 && (slide != 1 || k != 5))
 				{
-					int day = k + 4 * slide - 1;
+					int day = (k + 4 * slide - 1) % 7;
 					set_region(&time, n, day);
 					n++;
 					slide = 0;
@@ -221,7 +216,6 @@ static void set(void)
 					n++;
 					if(n == region_count)
 					{
-						time.year -= 1900;
 						rtc_setTime(time);
 						return;
 					}

demo/test_timer.c

@@ -22,6 +22,7 @@ static clock_config_t conf;
 static volatile int elapsed_timer = -1;
 static volatile int elapsed_rtc = -1;
 static int cb_id = -1;
+static timer_t *htimer = NULL;
 
 static void timing_rtc(void)
 {
@@ -35,7 +36,11 @@ static void timing_timer(void)
 
 static void timing_start(void)
 {
-	timer_start(TIMER_USER, 64, Clock_Hz, timing_timer, NULL, 0);
+	uint32_t delay = clock_setting(64, Clock_Hz);
+	htimer = htimer_setup(timer_user, delay, timer_Po_4, 0);
+	timer_attach(htimer, timing_timer, NULL);
+	timer_start(htimer);
+
 	rtc_cb_edit(cb_id, RTCFreq_64Hz, timing_rtc);
 
 	elapsed_timer = 0;
@@ -253,8 +258,8 @@ void test_timer(void)
 		switch(getkey_opt(Getkey_NoOption, 1))
 		{
 		case KEY_EXIT:
-			timer_stop(TIMER_USER);
 			rtc_cb_end(cb_id);
+			timer_stop(htimer);
 			return;
 
 		case KEY_F1:

include/clock.h

@@ -10,6 +10,8 @@
 #ifndef	_CLOCK_H
 #define	_CLOCK_H
 
+#include <stdint.h>
+
 //---
 //	Sleep functions.
 //---
@@ -21,12 +23,16 @@
 void sleep(void);
 
 /*
-	sleep_ms(), sleep_us()
-	Sleeps for the given number of milliseconds / microseconds using the
-	TIMER_USER timer. The actual sleep time will always be slightly less
-	than requested.
+	sleep_ms()
+	Sleeps for the given number of milliseconds using a virtual timer.
 */
 void sleep_ms(int ms_delay);
+
+/*
+	sleep_us()
+	Sleeps for the given number of microseconds using the hardware timer
+	timer_user.
+*/
 void sleep_us(int us_delay);
 
 
@@ -83,7 +89,7 @@ typedef struct
 	Normally you need not use this function when setting up timers because
 	timer_start() handles this conversion for you.
 */
-int clock_setting(int duration, enum ClockUnit unit);
+uint32_t clock_setting(int duration, enum ClockUnit unit);
 
 /*
 	clock_config()

include/events.h

@@ -9,26 +9,31 @@
 #ifndef	_EVENTS_H
 #define	_EVENTS_H
 
+#include <timer.h>
+
 /*
 	event_type_t
 	Something user programs will surely use most often.
 */
 typedef enum
 {
-	EventType_None		= 0,
-	ET_None			= EventType_None,
+	EventType_None			= 0,
+	ET_None				= EventType_None,
 
-	EventType_User		= 1,
-	ET_User			= EventType_User,
+	EventType_User			= 1,
+	ET_User				= EventType_User,
 
-	EventType_KeyPressed	= 2,
-	ET_KeyPress		= EventType_KeyPressed,
+	EventType_KeyPressed		= 2,
+	ET_KeyPress			= EventType_KeyPressed,
 
-	EventType_KeyRepeated	= 3,
-	ET_KeyRepeat		= EventType_KeyRepeated,
+	EventType_KeyRepeated		= 3,
+	ET_KeyRepeat			= EventType_KeyRepeated,
 
-	EventType_KeyReleased	= 4,
-	ET_KeyRel		= EventType_KeyReleased,
+	EventType_KeyReleased		= 4,
+	ET_KeyRel			= EventType_KeyReleased,
+
+	EventType_TimerUnderflow	= 5,
+	ET_Timer			= EventType_TimerUnderflow,
 
 } event_type_t;
 
@@ -47,6 +52,8 @@ typedef struct
 		void *data;
 		// For ET_KeyPress, ET_KeyRepeat and ET_KeyRel.
 		int key;
+		// For ET_Timer.
+		timer_t *timer;
 	};
 
 } event_t;

include/internals/modules.h

@@ -0,0 +1,12 @@
+#ifndef	_INTERNALS_MODULES_H
+#define	_INTERNALS_MODULES_H
+
+/*
+	mod_init()
+	Initializes the module data to make register access cross-platform. The
+	MPU needs to have been detected or this function will yield wrong
+	results.
+*/
+void mod_init(void);
+
+#endif	// _INTERNALS_MODULES_H

include/internals/rtc.h

@@ -14,7 +14,7 @@
 */
 struct rtc_cb
 {
-	enum RTCFrequency freq;
+	rtc_frequency_t freq;
 	int id;
 
 	void (*callback)(void);
@@ -24,6 +24,19 @@ struct rtc_cb
 // The callback array.
 struct rtc_cb cb_array[RTC_CB_ARRAY_SIZE];
 
+/*
+	rtc_perodic_interrupt()
+	Handles periodic interrupts and calls the callbacks.
+*/
+void rtc_periodic_interrupt(void);
+
+/*
+	rtc_cb_interrupt()
+	Calls the RTC callbacks if necessary, and updates the repeat counts.
+	Should only be called when RTC periodic interrupts occur.
+*/
+void rtc_cb_interrupt(void);
+
 /*
 	struct mod_rtc
 	This structure describes the arrangement of RTC register in the memory.

include/internals/timer.h

@@ -1,49 +1,76 @@
 #ifndef	_INTERNALS_TIMER_H
-#define	_INTERNALS_TIMER_H	1
+#define	_INTERNALS_TIMER_H
+
+#include <timer.h>
+#include <stdint.h>
 
 /*
-	struct Timer
-	This structure holds information for a running timer.
+	timer_t
+	A virtual or hardware timer. We need to declare the struct timer_t name
+	so that we can forward-reference it.
 */
-struct Timer
+typedef struct timer_t
 {
+	// Current delay, how much time elapsed since last interrupt occurred,
+	// and how many repeats are left.
+	int ms_delay;
+	int ms_elapsed;
+	int repeats_left;
+
+	// Is the virtual slot free? Is the virtual timer active?
+	uint8_t	used		:1;
+	uint8_t	active		:1;
+	// Is this a virtual timer? Is this the virtual timer support?
+	uint8_t virtual		:1;
+	uint8_t vsupport	:1;
+	// How many events do I have received but not executed?
+	uint8_t	events		:4;
+
+	// Callback function (NULL for event-firing timers) and its argument.
 	void *callback;
-	void *data;
-	int repeats;
-};
+	void *argument;
 
-extern struct Timer timers[3];
+} timer_t;
+
+// Hardware timers.
+extern timer_t htimers[3];
+// Virtual timers.
+extern timer_t vtimers[TIMER_SLOTS];
 
 /*
-	struct mod_tmu
-	This structure holds information about the timer unit (peripheral
-	module) registers.
+	timer_interrupt()
+	Handles the interrupt for the given timer channel.
 */
-struct mod_tmu
-{
-	unsigned int TCOR;	// Timer constant register.
-	unsigned int TCNT;	// Timer counter.
-
-	union
-	{
-		unsigned short WORD;
-		struct
-		{
-			unsigned	:7;
-			unsigned UNF	:1;	// Underflow flag.
-			unsigned	:2;
-			unsigned UNIE	:1;	// Underflow interrupt enable.
-			unsigned CKEG	:2;	// Clock edge (SH7705 only).
-			unsigned TPSC	:3;	// Timer prescaler.
-		};
-	} TCR;	// Timer control register.
-};
+void timer_interrupt(int channel);
 
 /*
-	timer_get()
-	Returns the timer and TSTR register addresses.
+	timer_callback_event()
+	Executes the callback of a timer, or pushes a new timer event depending
+	on the timer configuration. Also reduces the amount of repeats left and
+	clears the active flag (or stops the hardware timer) if this number
+	falls from one to zero.
 */
-void timer_get(int timer, volatile struct mod_tmu **tmu,
-	volatile unsigned char **tstr);
+void timer_callback_event(timer_t *timer);
+
+/*
+	vtimer_interrupt()
+	Interrupt handling subsystem for the virtual timers.
+*/
+void vtimer_interrupt(void);
+
+/*
+	vtimer_updateOne()
+	Update the virtual timer hardware support timer, knowing that a virtual
+	timer with the given delay has been started.
+*/
+void vtimer_updateOne(int additional_delay_ms);
+
+/*
+	vtimer_updateAll()
+	Updates the virtual timer hardware support after computing the GCD of
+	all virtual timers delays. This is rather long so avoid calling this
+	when possible.
+*/
+void vtimer_updateAll(void);
 
 #endif	// _INTERNALS_TIMER_H

include/modules/macros.h

@@ -0,0 +1,48 @@
+#ifndef	_MODULES_MACROS_H
+#define	_MODULES_MACROS_H
+
+#include <stdint.h>
+
+// Fixed-width types for bit field are totally meaningless.
+typedef unsigned uint;
+
+/*
+	byte_union()
+	Union between an uint8_t 'byte' attribute and a provided bit-field
+	structure that describe the contents of the byte.
+*/
+#define	byte_union(name, fields)		\
+	union					\
+	{					\
+		uint8_t byte;			\
+		struct { fields }		\
+		__attribute__((packed));	\
+	} __attribute__((packed)) name
+
+/*
+	word_union()
+	Union between an uint16_t 'word' attribute and a provided bit-field
+	structure that describe the contents of the word.
+*/
+#define word_union(name, fields)		\
+	union					\
+	{					\
+		uint16_t word;			\
+		struct { fields }		\
+		__attribute__((packed));	\
+	} __attribute__((packed)) name
+
+/*
+	lword_union()
+	Union between an uint32_t 'lword' attribute and a provided bit-field
+	structure that describe the contents of the longword.
+*/
+#define	lword_union(name, fields)		\
+	union					\
+	{					\
+		uint32_t lword;			\
+		struct { fields }		\
+		__attribute__((packed));	\
+	} __attribute__((packed)) name
+
+#endif	// _MODULES_MACROS_H

include/modules/timer.h

@@ -0,0 +1,64 @@
+#ifndef	_MODULES_TIMER_H
+#define	_MODULES_TIMER_H
+
+#include <modules/macros.h>
+#include <stdint.h>
+
+/*
+	mod_tmu_timer_t
+	Registers of a single timer.
+*/
+typedef struct
+{
+	uint32_t	TCOR;		/* Timer constant register */
+	uint32_t	TCNT;		/* Timer counter */
+
+	word_union(TCR,
+		uint		:7;
+		uint	UNF	:1;	/* Underflow flag */
+		uint		:2;
+		uint	UNIE	:1;	/* Underflow interrupt enable */
+		uint	CKEG	:2;	/* Clock edge (SH7705) */
+		uint	TPSC	:3;	/* Timer prescaler */
+	);
+
+	uint16_t	:16;
+
+} __attribute__((packed, aligned(4))) mod_tmu_timer_t;
+
+/*
+	mod_tmu_tstr_t
+	The timer start register.
+*/
+typedef struct
+{
+	byte_union(,
+		uint		:5;
+		uint	STR2	:1;	/* Counter start 2 */
+		uint	STR1	:1;	/* Counter start 1 */
+		uint	STR0	:1;	/* Counter start 0 */
+	);
+
+} __attribute__((packed)) mod_tmu_tstr_t;
+
+/*
+	mod_tmu_t (resides into gint memory)
+	Basically three timer units and an additional register to control who's
+	running.
+*/
+typedef struct
+{
+	/* Timer configurations */
+	volatile mod_tmu_timer_t	*timers[3];
+	/* Timer start register */
+	volatile mod_tmu_tstr_t		*TSTR;
+	/* Timer input capture 2 (SH7705) */
+	volatile const uint32_t		*TCPR2;
+
+} mod_tmu_t;
+
+// The actual thing is there. It's initialized by gint at startup and contains
+// addresses and information suitable for the current platform.
+extern volatile mod_tmu_t TMU;
+
+#endif	// _MODULES_TIMER

include/rtc.h

@@ -9,38 +9,41 @@
 #ifndef	_RTC_H
 #define	_RTC_H	1
 
+#include <stdint.h>
+
 //---
 //	Time access.
 //---
 
 /*
-	struct RTCTime
+	rtc_time_t
 	Defines a point in time.
 */
-struct RTCTime
+typedef struct
 {
-	int seconds;		// Seconds in range 0-59
-	int minutes;		// Minutes in range 0-59
-	int hours;		// Hours in range 0-23
-	int month_day;		// Day of month in range 1-31
-	int month;		// Month in range 0-11
-	int year;		// Years (full value)
-	int week_day;		// Day of week in range 0(Sunday)-6(Saturday).
-};
+	uint8_t seconds;	// Seconds in range 0-59
+	uint8_t minutes;	// Minutes in range 0-59
+	uint8_t hours;		// Hours in range 0-23
+	uint8_t month_day;	// Day of month in range 1-31
+	uint8_t month;		// Month in range 0-11
+	uint8_t week_day;	// Day of week in range 0(Sunday)-6(Saturday).
+	uint16_t year;		// Years (around 2000)
+
+} rtc_time_t;
 
 /*
 	rtc_getTime()
 	Reads the current time from the RTC. There is no guarantee that the
 	week day is correct (use the time API for that).
 */
-struct RTCTime rtc_getTime(void);
+rtc_time_t rtc_getTime(void);
 
 /*
 	rtc_setTime()
 	Sets the time in the RTC registers. The week day is set to 0 if greater
 	than 6. Other fields are not checked.
 */
-void rtc_setTime(struct RTCTime time);
+void rtc_setTime(rtc_time_t time);
 
 
 
@@ -49,11 +52,11 @@ void rtc_setTime(struct RTCTime time);
 //---
 
 /*
-	enum RTCFrequency
+	rtc_frequency_t
 	Describes the possible frequencies available for the real-time clock
 	interrupt.
 */
-enum RTCFrequency
+typedef enum
 {
 	RTCFreq_500mHz	= 7,
 	RTCFreq_1Hz	= 6,
@@ -63,7 +66,8 @@ enum RTCFrequency
 	RTCFreq_64Hz	= 2,
 	RTCFreq_256Hz	= 1,
 	RTCFreq_None	= 0,
-};
+
+} rtc_frequency_t;
 
 /*
 	rtc_cb_add()
@@ -74,7 +78,7 @@ enum RTCFrequency
 	The number of repeats may be set to 0, in which case the callback is
 	called indefinitely unless the user calls rtc_cb_end().
 */
-int rtc_cb_add(enum RTCFrequency freq, void (*function)(void), int repeats);
+int rtc_cb_add(rtc_frequency_t freq, void (*function)(void), int repeats);
 
 /*
 	rtc_cb_end()
@@ -93,29 +97,6 @@ void rtc_cb_end(int id);
 	can set the function to NULL or the frequency to RTCFreq_None to
 	temporarily disable the callback.
 */
-int rtc_cb_edit(int id, enum RTCFrequency new_freq,
-	void (*new_function)(void));
-
-
-
-//---
-//	Internal API.
-//	Referenced here for documentation purposes only. Do not call.
-//---
-
-/*
-	rtc_interrupt()
-	Handles an RTC interrupt by calling the callback.
-*/
-void rtc_interrupt(void);
-void rtc_interrupt_7705(void);
-void rtc_interrupt_7305(void);
-
-/*
-	rtc_cb_interrupt()
-	Handles an RTC interrupt. Calls the RTC callbacks if necessary, and
-	updates the repeat counts.
-*/
-void rtc_cb_interrupt(void);
+int rtc_cb_edit(int id, rtc_frequency_t new_freq, void (*new_function)(void));
 
 #endif	// _RTC_H

include/timer.h

@@ -11,106 +11,157 @@
 #define	_TIMER_H	1
 
 #include <clock.h>
+#include <stdint.h>
+#include <stddef.h>
+
+// The timer object is manipulated by the module; the user needs not access it
+// directly. Its contents are defined in <internals/timer.h>.
+struct timer_t;
+typedef struct timer_t timer_t;
 
 //---
-//	Constants.
+//	Virtual timer API
+//	Gint allows users to create virtual timers with 1-ms precision to
+//	handle an important amount of timed events. The amount of virtual
+//	timers available is gapped by the TIMER_SLOTS parameter, but this
+//	parameter can be customized when building the library; thus, the
+//	amount of usable virtual timers is not limited.
 //---
 
-// Timer identifiers.
-#define	TIMER_0		0
-#define TIMER_TMU0	TIMER_0
-#define	TIMER_1		1
-#define TIMER_TMU1	TIMER_1
-#define	TIMER_2		2
-#define	TIMER_TMU2	TIMER_2
-// Timer function identifiers.
-#define	TIMER_KEYBOARD	TIMER_TMU0
-#define	TIMER_GRAY	TIMER_TMU1
-#define	TIMER_USER	TIMER_TMU2
+#ifndef	TIMER_SLOTS
+#define	TIMER_SLOTS	16
+#endif
 
-// Timer prescalers.
-#define	TIMER_Po_4	0
-#define	TIMER_Po_16	1
-#define TIMER_Po_64	2
-#define TIMER_Po_256	3
-#define TIMER_TCLK	5
+/*
+	timer_create()
+	Basic timer configuration. This function creates a virtual timer and
+	configures its delay and repetition count. It returns a virtual timer
+	object that will be used by other functions. At most TIMER_SLOTS
+	virtual timers can be used at the same time: this function returns NULL
+	if there is no new slot available.
+	By default a virtual timer configured by timer_configure() will fire
+	ET_Timer events, which the user will need to catch. The user should
+	then execute some action.
+	There is another option: the user may call timer_attach() to attach a
+	callback to a virtual timer. A virtual timer which has a callback
+	attached will not fire any ET_Timer event and will call the callback
+	automatically instead.
+*/
+timer_t *timer_create(int delay_ms, int repeats);
+
+/*
+	timer_destroy()
+	Destroys a virtual timer. This virtual timer pointer becomes invalid
+	and should not be used anymore.
+*/
+void timer_destroy(timer_t *virtual_timer);
 
 
 
 //---
-//	Public API.
+//	Hardware timer API
+//	Gint provides access to hardware timer. These timer offer more or less
+//	microsecond-level control. However, the user should ensure, when using
+//	hardware timers, that they are not overriding the configuration of
+//	timers that are already running -- gint won't check.
 //---
 
+/*
+	timer_hard_t
+	Available hardware timers. The user can use timer_user freely, but
+	timer_gray and timer_virtual should not be used as long as the gray
+	engine or virtual timers are running (respectively).
+*/
+typedef enum
+{
+	timer_tmu0	= 0,
+	timer_virtual	= timer_tmu0,
+
+	timer_tmu1	= 1,
+	timer_gray	= timer_tmu1,
+
+	timer_tmu2	= 2,
+	timer_user	= timer_tmu2,
+
+} timer_hard_t;
+
+/*
+	timer_input_t
+	Available input clocks for the hardware timer:
+	  - Po/4	Peripheral clock (frequency divided by 4)
+	  - Po/16	Peripheral clock (frequency divided by 16)
+	  - Po/64	Peripheral clock (frequency divided by 64)
+	  - Po/256	Peripheral clock (frequency divided by 256)
+	  - TCLK	External clock
+	I'm not totally sure there is any signal on the external clock, so
+	don't use it unless you know what you are doing.
+*/
+typedef enum
+{
+	timer_Po_4	= 0,
+	timer_Po_16	= 1,
+	timer_Po_64	= 2,
+	timer_Po_256	= 3,
+	timer_tclk	= 5,
+
+} timer_input_t;
+
+/*
+	htimer_setup()
+	Configures a hardware timer. By default hardware timers generates
+	ET_Timer events but catching them may take some time, especially if
+	there are other events waiting in the queue. For increased timing, and
+	for fast timers, the user should consider using callbacks instead.
+	Returns a hardware timer object.
+	Returns the correct timer structure if the requested timer is free and
+	NULL otherwise.
+*/
+timer_t *htimer_setup(timer_hard_t id, uint32_t constant, timer_input_t input,
+	int repeats);
+
+/*
+	htimer_reload()
+	Reloads a hardware timer without starting or stopping it.
+*/
+void htimer_reload(timer_hard_t id, uint32_t new_constant);
+
+
+
+//---
+//	Common API
+//	The following functions work with both virtual and hardware timers.
+//---
+
+/*
+	timer_attach()
+	This function attaches a callback to a virtual or hardware timer. A
+	timer with a callback attached will stop firing ET_Timer events and
+	will call the callback function directly instead.
+	The type signature of the function should be as follows:
+	  - void callback(void)            if argument == NULL
+	  - void callback(void *argument)  if argument is non-NULL
+	In the latter case, the argument pointer will be passed to the callback
+	function.
+*/
+void timer_attach(timer_t *timer, void *callback, void *argument);
+
 /*
 	timer_start()
-	Configures and starts a timer. The timer argument expects a timer name.
-	You can use TIMER_USER anytime. You may also use TIMER_GRAY if you're
-	not running the gray engine.
-	Unit names are defined in the clock.h header and must be one of the
-	following:
-	  - Clock_us	(microseconds)
-	  - Clock_ms	(milliseconds)
-	  - Clock_s	(seconds)
-	  - Clock_Hz	(hertz)
-	  - Clock_kHz	(kilohertz)
-	  - Clock_MHz	(megahertz)
-	The number of repeats may to set to 0. In this case, the timer will not
-	stop until timer_stop() is explicitly called.
-	The callback is expected to be a function of the following type:
-	  - void callback(void)        if data == NULL
-	  - void callback(void *data)  if data is non-NULL
-	In the latter case, the data pointer will be passed as argument to the
-	callback function.
+	Starts a virtual or hardware timer. If the timer has a callback
+	attached, then the callback function will start being called regularly;
+	otherwise, the timer will start pushing ET_Timer events to the event
+	queue. It is advised, not to change a timer's configuration while it's
+	running.
 */
-void timer_start(int timer, int delay_or_frequency, enum ClockUnit unit,
-	void *callback, void *data, int repeats);
-
-/*
-	timer_start2()
-	Basically the same as timer_start(), but uses a clock-count delay and a
-	prescaler. The possible values for the prescaler are dividers of the
-	peripheral clock frequency Po:
-	- TIMER_Po_4
-	- TIMER_Po_16
-	- TIMER_Po_64
-	- TIMER_Po_256
-	- TIMER_TCLK
-*/
-void timer_start2(int timer, int delay, int prescaler, void *callback,
-	void *data, int repeats);
+void timer_start(timer_t *timer);
 
 /*
 	timer_stop()
-	Stops the given timer. This function may be called even if the timer is
-	not running.
+	Stops a timer. If the argument is virtual timer, it is paused and can
+	be started again later.
+	If it's a hardware timer, it is freed and made accessible to other
+	uses. It should be set up again before being started.
 */
-void timer_stop(int timer);
-
-/*
-	timer_reload()
-	Reloads the given timer with the supplied constant. Starts the timer if
-	it was stopped.
-*/
-void timer_reload(int timer, int new_delay_or_frequency, enum ClockUnit unit);
-
-/*
-	timer_reload2()
-	Same as timer_reload(), but again uses the native clock count. The
-	prescaler may not be changed.
-*/
-void timer_reload2(int timer, int new_delay);
-
-
-
-//---
-//	Internal API.
-//	Referenced for documentation purposes only. Do not call.
-//---
-
-/*
-	timer_interrupt()
-	Handles the interrupt for the given timer.
-*/
-void timer_interrupt(int timer);
+void timer_stop(timer_t *timer);
 
 #endif // _TIMER_H

src/clock/clock.c

@@ -1,6 +1,6 @@
 #include <clock.h>
 #include <timer.h>
-#include <internals/timer.h>
+#include <modules/timer.h>
 #include <rtc.h>
 #include <stddef.h>
 #include <mpu.h>
@@ -19,9 +19,9 @@ static clock_config_t conf = {
 	Several units can be used. Be aware that the result is approximate, and
 	very high frequencies or very short delays will yield important errors.
 */
-int clock_setting(int duration, enum ClockUnit unit)
+uint32_t clock_setting(int duration, enum ClockUnit unit)
 {
-	if(conf.Pphi_f <= 0) return -1;
+	if(conf.Pphi_f <= 0) return 0xffffffff;
 	uint64_t f = conf.Pphi_f >> 2;
 	uint64_t result;
 
@@ -74,30 +74,42 @@ void sleep(void)
 	);
 }
 
-/*
-	sleep_ms(), sleep_us()
-	Sleeps for the given number of milliseconds / microseconds using the
-	TIMER_USER timer. The actual sleep time will always be slightly less
-	than requested.
-*/
-
-static void sleep_callback(void *flag)
+static void sleep_callback(void *arg)
 {
-	*((int *)flag) = 1;
+	int *flag = arg;
+	*flag = 1;
 }
 
+/*
+	sleep_ms()
+	Sleeps for the given number of milliseconds using a virtual timer.
+*/
 void sleep_ms(int ms_delay)
 {
-	sleep_us(1000 * ms_delay);
+	volatile int sleep_done = 0;
+
+	timer_t *timer = timer_create(ms_delay, 1);
+	timer_attach(timer, sleep_callback, (void *)&sleep_done);
+	timer_start(timer);
+
+	while(!sleep_done) sleep();
 }
+
+/*
+	sleep_us()
+	Sleeps for the given number of microseconds using the hardware timer
+	timer_user.
+*/
 void sleep_us(int us_delay)
 {
 	volatile int sleep_done = 0;
-	timer_start(TIMER_USER, us_delay, Clock_us, sleep_callback,
-		(void *)&sleep_done, 1);
+	const uint32_t constant = clock_setting(us_delay, Clock_us);
 
-	do sleep();
-	while(!sleep_done);
+	timer_t *timer = htimer_setup(timer_user, constant, timer_Po_4, 1);
+	timer_attach(timer, sleep_callback, (void *)&sleep_done);
+	timer_start(timer);
+
+	while(!sleep_done) sleep();
 }
 
 
@@ -109,6 +121,7 @@ void sleep_us(int us_delay)
 // Indicates whether the measurements are finished.
 static volatile int clock_measure_done = 0;
 // Once again SH7705 and SH7305 need different methods...
+static timer_t *htimer_7705 = NULL;
 static int cb_id_7705 = -1;
 static void clock_measure_7705(void);
 static void clock_compute_7305(void);
@@ -128,25 +141,8 @@ void clock_measure(void)
 	// P_phi using a timer/RTC combination, and we deduce CKIO.
 	if(isSH3())
 	{
-		// We prepare the timer manually, without starting it, so that
-		// we only have to push the running bit to start it when the
-		// measurements begin. This might look of little effect but it
-		// makes the precision jump from ~97% to more than 99%.
-		volatile struct mod_tmu *tmu;
-		timer_get(TIMER_USER, &tmu, NULL);
-
-		tmu->TCOR	= 0xffffffff;
-		tmu->TCNT	= tmu->TCOR;
-		tmu->TCR.TPSC	= TIMER_Po_4;
-
-		tmu->TCR.UNF	= 0;
-		tmu->TCR.UNIE	= 1;
-		tmu->TCR.CKEG	= 0;
-
-		timers[TIMER_USER].callback	= NULL;
-		timers[TIMER_USER].data		= NULL;
-		timers[TIMER_USER].repeats	= 0;
-
+		htimer_7705 = htimer_setup(timer_user, 0xffffffff, timer_Po_4,
+			1);
 		cb_id_7705 = rtc_cb_add(RTCFreq_256Hz, clock_measure_7705, 0);
 	}
 
@@ -226,7 +222,7 @@ static void clock_compute_7305(void)
 	Given the number of P_phi / 4 timer ticks elapsed between two RTC
 	256 Hz interrupts, determines the clock configuration.
 */
-static void clock_measure_7705_finalize(int elapsed)
+static void clock_measure_7705_finalize(uint32_t elapsed)
 {
 	volatile unsigned int *FRQCR	= (void *)0xffffff80;
 
@@ -254,13 +250,10 @@ static void clock_measure_7705_finalize(int elapsed)
 */
 static void clock_measure_7705_callback(void)
 {
-	timer_stop(TIMER_USER);
+	timer_stop(htimer_7705);
 	rtc_cb_end(cb_id_7705);
 
-	volatile struct mod_tmu *tmu;
-	timer_get(TIMER_USER, &tmu, NULL);
-	int elapsed = 0xffffffff - tmu->TCNT;
-
+	uint32_t elapsed = 0xffffffff - TMU.timers[timer_user]->TCNT;
 	clock_measure_7705_finalize(elapsed);
 	clock_measure_done = 1;
 }
@@ -274,9 +267,6 @@ static void clock_measure_7705_callback(void)
 */
 static void clock_measure_7705(void)
 {
-	volatile unsigned char *tstr;
-	timer_get(TIMER_USER, NULL, &tstr);
-
-	*tstr |= (1 << TIMER_USER);
+	timer_start(htimer_7705);
 	rtc_cb_edit(cb_id_7705, RTCFreq_256Hz, clock_measure_7705_callback);
 }

src/core/crt0.c

@@ -8,6 +8,7 @@
 #include <internals/clock.h>
 #include <clock.h>
 #include <gint.h>
+#include <internals/modules.h>
 
 int main(void);
 
@@ -58,7 +59,7 @@ __attribute__((section(".pretext.entry"))) int start(void)
 	dg->stage	= stage_startup;
 
 	// Exception records: what kind of exceptions / TLB faults / interrupts
-	// occured last to get some trace in case of crash.
+	// occurred last to get some trace in case of crash.
 	dg->excepts	= 0;
 	for(size_t i = 0; i < sizeof dg->except_vect; i++)
 		dg->except_vect[i] = 0;
@@ -67,7 +68,7 @@ __attribute__((section(".pretext.entry"))) int start(void)
 	dg->expevt	= 0x00000000;
 	dg->tea		= 0x00000000;
 
-	// Memory map: provides information about alignement and the relative
+	// Memory map: provides information about alignment and the relative
 	// size and position of each section, as well as read-only / read-write
 	// types of addresses.
 	dg->section_text.address	= (uint32_t)&btext;
@@ -107,7 +108,10 @@ __attribute__((section(".pretext.entry"))) int start(void)
 	dg->stage	= stage_mmu;
 	#endif
 
-	// Initializing gint.
+	// Detecting the MPU type, initializing the register module addresses,
+	// and initializing gint.
+	mpu_init();
+	mod_init();
 	gint_init();
 
 	#ifdef	GINT_DIAGNOSTICS

src/core/init_quit.c

@@ -29,11 +29,6 @@ void gint_init(void)
 	uint32_t *ptr = &bgint;
 	uint32_t *src = &gint_data;
 
-	// This initialization routine is usually called before any
-	// constructor. We want to ensure that the MPU type is detected, but
-	// mpu_init() hasn't been called yet.
-	mpu_init();
-
 	// Loading the interrupt handler into the memory.
 	while(ptr < &egint) *ptr++ = *src++;
 

src/core/interrupts.c

@@ -1,6 +1,6 @@
 #include <internals/interrupts.h>
-#include <timer.h>
-#include <rtc.h>
+#include <internals/timer.h>
+#include <internals/rtc.h>
 
 /*
 	inth_timer_underflow()
@@ -17,5 +17,5 @@ void inth_timer_underflow(uint32_t channel)
 */
 void inth_rtc_periodic(void)
 {
-	rtc_interrupt();
+	rtc_periodic_interrupt();
 }

src/core/modules.c

@@ -0,0 +1,49 @@
+#include <modules/timer.h>
+#include <stddef.h>
+#include <mpu.h>
+
+//---
+//	Structure information
+//	Here resides most of the platform-dependent register configuration.
+//	Module structures are arranged to mask as much as possible hardware
+//	differences to the user. When it becomes impossible to do so at
+//	compile-time, gint provides functions to ensure that the user does not
+//	confront to the hardware directly.
+//---
+
+volatile mod_tmu_t TMU;
+
+
+
+//---
+//	Initializer
+//---
+
+static void mod_init_7705(void)
+{
+	TMU.timers[0]	= (void *)0xfffffe94;
+	TMU.timers[1]	= (void *)0xfffffea0;
+	TMU.timers[2]	= (void *)0xfffffeac;
+	TMU.TSTR	= (void *)0xfffffe92;
+	TMU.TCPR2	= (void *)0xfffffeb8;
+}
+
+static void mod_init_7305(void)
+{
+	TMU.timers[0]	= (void *)0xa4490008;
+	TMU.timers[1]	= (void *)0xa4490014;
+	TMU.timers[2]	= (void *)0xa4490020;
+	TMU.TSTR	= (void *)0xa4490004;
+	TMU.TCPR2	= NULL;
+}
+
+/*
+	mod_init()
+	Initializes the module data to make register access cross-platform. The
+	MPU needs to have been detected or this function will yield wrong
+	results.
+*/
+void mod_init(void)
+{
+	isSH3() ? mod_init_7705() : mod_init_7305();
+}

src/gray/gray_engine.c

@@ -19,7 +19,7 @@ static int delays[2];
 
 static int runs = 0;
 
-#define	GRAY_PRESCALER	TIMER_Po_64
+static timer_t *gray_timer = NULL;
 
 
 
@@ -33,7 +33,8 @@ static int runs = 0;
 */
 void gray_interrupt(void)
 {
-	timer_reload2(TIMER_GRAY, delays[(~current) & 1]);
+	htimer_reload(timer_gray, delays[(~current) & 1]);
+
 	screen_display(vrams[current]);
 	current ^= 1;
 }
@@ -68,8 +69,10 @@ void gray_start(void)
 {
 	if(runs) return;
 
-	timer_start2(TIMER_GRAY, delays[0], GRAY_PRESCALER, gray_interrupt,
-		NULL, 0);
+	gray_timer = htimer_setup(timer_gray, delays[0], timer_Po_64, 0);
+	timer_attach(gray_timer, gray_interrupt, NULL);
+	timer_start(gray_timer);
+
 	current &= 1;
 	runs = 1;
 }
@@ -81,9 +84,7 @@ void gray_start(void)
 */
 void gray_stop(void)
 {
-	if(!runs) return;
-
-	timer_stop(TIMER_GRAY);
+	timer_stop(gray_timer);
 	runs = 0;
 
 	display_useVRAM(display_getLocalVRAM());

src/rtc/rtc_callback.c

@@ -7,7 +7,7 @@ struct rtc_cb cb_array[RTC_CB_ARRAY_SIZE] = { 0 };
 // Callback identifier (unique).
 static int unique_id = 1;
 // Current RTC interrupt frequency.
-static enum RTCFrequency rtc_freq = RTCFreq_None;
+static rtc_frequency_t rtc_freq = RTCFreq_None;
 // 256-Hz tick count. This counter is stopped when no callback is registered.
 static unsigned elapsed256 = 0;
 
@@ -21,7 +21,7 @@ static unsigned elapsed256 = 0;
 */
 static void rtc_cb_update(void)
 {
-	enum RTCFrequency max = RTCFreq_None;
+	rtc_frequency_t max = RTCFreq_None;
 	int n;
 
 	for(n = 0; n < RTC_CB_ARRAY_SIZE; n++) if(cb_array[n].id)
@@ -46,7 +46,7 @@ static void rtc_cb_update(void)
 	The number of repeats may be set to 0, in which case the callback is
 	called indefinitely unless the user calls rtc_cb_end().
 */
-int rtc_cb_add(enum RTCFrequency freq, void (*function)(void), int repeats)
+int rtc_cb_add(rtc_frequency_t freq, void (*function)(void), int repeats)
 {
 	int n = 0;
 	if(freq == RTCFreq_None || !function || repeats < 0) return -2;
@@ -92,7 +92,7 @@ void rtc_cb_end(int id)
 	  -2	Invalid parameters
 	This function never removes a callback. Call rtc_cb_end() for this.
 */
-int rtc_cb_edit(int id, enum RTCFrequency new_freq,
+int rtc_cb_edit(int id, rtc_frequency_t new_freq,
 	void (*new_function)(void))
 {
 	if(new_freq < 0 || new_freq > 7) return -2;

src/rtc/rtc_getTime.c

@@ -21,18 +21,24 @@ static int integer16(int bcd)
 	Reads the current time from the RTC. There is no guarantee that the
 	week day is correct (use the time API for that).
 */
-struct RTCTime rtc_getTime(void)
+rtc_time_t rtc_getTime(void)
 {
 	volatile struct mod_rtc *rtc = isSH3() ? RTC_SH7705 : RTC_SH7305;
-	struct RTCTime time;
+	rtc_time_t time;
 
-	time.seconds	= integer8(rtc->RSECCNT.BYTE);
-	time.minutes	= integer8(rtc->RMINCNT.BYTE);
-	time.hours	= integer8(rtc->RHRCNT.BYTE);
-	time.month_day	= integer8(rtc->RDAYCNT.BYTE);
-	time.month	= integer8(rtc->RMONCNT.BYTE);
-	time.year	= integer16(rtc->RYRCNT.WORD);
-	time.week_day	= rtc->RWKCNT;
+	do
+	{
+		rtc->RCR1.CF = 0;
+
+		time.seconds	= integer8(rtc->RSECCNT.BYTE);
+		time.minutes	= integer8(rtc->RMINCNT.BYTE);
+		time.hours	= integer8(rtc->RHRCNT.BYTE);
+		time.month_day	= integer8(rtc->RDAYCNT.BYTE);
+		time.month	= integer8(rtc->RMONCNT.BYTE);
+		time.year	= integer16(rtc->RYRCNT.WORD);
+		time.week_day	= rtc->RWKCNT;
+	}
+	while(rtc->RCR1.CF != 0);
 
 	return time;
 }

src/rtc/rtc_interrupt.c

@@ -2,11 +2,13 @@
 #include <rtc.h>
 #include <mpu.h>
 
+int rtc_carry_flag = 0;
+
 /*
-	rtc_interrupt()
+	rtc_periodic_interrupt()
 	Handles an RTC interrupt by calling the callback.
 */
-void rtc_interrupt(void)
+void rtc_periodic_interrupt(void)
 {
 	rtc_cb_interrupt();
 

src/rtc/rtc_setTime.c

@@ -22,15 +22,22 @@ static int bcd16(int integer)
 	Sets the time in the RTC registers. The week day is set to 0 if greater
 	than 6. Other fields are not checked.
 */
-void rtc_setTime(struct RTCTime time)
+void rtc_setTime(rtc_time_t time)
 {
 	volatile struct mod_rtc *rtc = isSH3() ? RTC_SH7705 : RTC_SH7305;
+	int wday = (time.week_day < 7) ? (time.week_day) : (0);
 
-	rtc->RSECCNT.BYTE	= bcd8(time.seconds);
-	rtc->RMINCNT.BYTE	= bcd8(time.minutes);
-	rtc->RHRCNT.BYTE	= bcd8(time.hours);
-	rtc->RDAYCNT.BYTE	= bcd8(time.month_day);
-	rtc->RMONCNT.BYTE	= bcd8(time.month);
-	rtc->RYRCNT.WORD	= bcd16(time.year);
-	rtc->RWKCNT		= time.week_day < 7 ? time.week_day : 0;
+	do
+	{
+		rtc->RCR1.CF = 0;
+
+		rtc->RSECCNT.BYTE	= bcd8(time.seconds);
+		rtc->RMINCNT.BYTE	= bcd8(time.minutes);
+		rtc->RHRCNT.BYTE	= bcd8(time.hours);
+		rtc->RDAYCNT.BYTE	= bcd8(time.month_day);
+		rtc->RMONCNT.BYTE	= bcd8(time.month);
+		rtc->RYRCNT.WORD	= bcd16(time.year);
+		rtc->RWKCNT		= wday;
+	}
+	while(rtc->RCR1.CF != 0);
 }

src/time/time.c

@@ -12,7 +12,7 @@
 */
 time_t time(time_t *timeptr)
 {
-	struct RTCTime rtc = rtc_getTime();
+	rtc_time_t rtc = rtc_getTime();
 	struct tm tm;
 	time_t calendar;
 

src/timer/common_api.c

@@ -0,0 +1,112 @@
+#include <timer.h>
+#include <internals/timer.h>
+#include <modules/timer.h>
+#include <events.h>
+
+/*
+	timer_attach()
+	Attaches a callback to a virtual or hardware timer.
+*/
+void timer_attach(timer_t *timer, void *callback, void *argument)
+{
+	if(!timer) return;
+
+	timer->callback = callback;
+	timer->argument = argument;
+}
+
+/*
+	timer_start()
+	Starts a virtual or hardware timer. If the timer has a callback
+	attached, then the callback function will start being called regularly;
+	otherwise, the timer will start pushing ET_Timer events to the event
+	queue. It is advised, not to change a timer's configuration while it's
+	running.
+*/
+void timer_start(timer_t *timer)
+{
+	if(!timer) return;
+	timer->active = 1;
+
+	if(timer->virtual) vtimer_updateOne(timer->ms_delay);
+	else TMU.TSTR->byte |= (1 << (timer - htimers));
+}
+
+/*
+	timer_stop()
+	Pauses a virtual or hardware timer. The timer stops counting and can be
+	started again later.
+*/
+void timer_stop(timer_t *timer)
+{
+	if(!timer) return;
+	timer->active = 0;
+
+	if(timer->virtual) vtimer_updateAll();
+	else
+	{
+		TMU.TSTR->byte &= ~(1 << (timer - htimers));
+		timer->used = 0;
+	}
+}
+
+/*
+	timer_interrupt()
+	Handles the interrupt for the given timer channel.
+*/
+void timer_interrupt(int channel)
+{
+	// Is this the virtual timer support?
+	if(htimers[channel].vsupport) vtimer_interrupt();
+	else timer_callback_event(&htimers[channel]);
+
+	// Clearing the interrupt flag.
+	TMU.timers[channel]->TCR.UNF = 0;
+}
+
+/*
+	timer_callback_event()
+	Executes the callback of a timer, or pushes a new timer event depending
+	on the timer configuration. Also reduces the amount of repeats left and
+	clears the active flag (or stops the hardware timer) if this number
+	falls from one to zero.
+*/
+void timer_callback_event(timer_t *timer)
+{
+	if(!timer) return;
+
+	// Callback-type timers.
+	if(timer->callback)
+	{
+		if(!timer->argument)
+		{
+			void (*fun)(void) = timer->callback;
+			fun();
+		}
+		else
+		{
+			void (*fun)(void *arg) = timer->callback;
+			fun(timer->argument);
+		}
+	}
+
+	// Event-type timers.
+	else
+	{
+		event_t event = {
+			.type	= ET_Timer,
+			.timer	= timer
+		};
+		event_push(event);
+	}
+
+	// Reducing the number of repeats and stopping the timer if required.
+	if(timer->repeats_left > 0)
+	{
+		if(!--timer->repeats_left)
+		{
+			if(timer->virtual) timer->active = 0;
+			else timer_stop(timer);
+		}
+	}
+}

src/timer/hardware_timers.c

@@ -0,0 +1,63 @@
+#include <timer.h>
+#include <internals/timer.h>
+#include <modules/timer.h>
+
+//---
+//	Public API
+//---
+
+timer_t htimers[3] = { 0 };
+
+/*
+	htimer_setup()
+	Configures a hardware timer.
+*/
+timer_t *htimer_setup(timer_hard_t id, uint32_t constant, timer_input_t input,
+	int repeats)
+{
+	if(id < 0 || id >= 3 || htimers[id].used) return NULL;
+	timer_t *timer = &htimers[id];
+
+	// We don't care about this.
+	timer->ms_delay		= 0;
+	timer->ms_elapsed	= 0;
+
+	timer->repeats_left	= repeats;
+
+	timer->used		= 1;
+	timer->active		= 0;
+	timer->virtual		= 0;
+	timer->vsupport		= 0;
+	timer->events		= 0;
+
+	timer->callback		= NULL;
+	timer->argument		= NULL;
+
+	// Time to set up the real thing.
+	volatile mod_tmu_timer_t *tmu = TMU.timers[id];
+
+	tmu->TCOR		= constant;
+	tmu->TCNT		= constant;
+	tmu->TCR.TPSC		= input;
+
+	tmu->TCR.UNF		= 0;	// Clear the interrupt flag.
+	tmu->TCR.UNIE		= 1;	// Enable underflow interrupt.
+	tmu->TCR.CKEG		= 0;	// Count on rising edge (SH7705).
+
+	return timer;
+}
+
+/*
+	htimer_reload()
+	Reloads a hardware timer without starting or stopping it.
+*/
+void htimer_reload(timer_hard_t id, uint32_t new_constant)
+{
+	volatile mod_tmu_timer_t *tmu = TMU.timers[id];
+
+	// This is not much but we want to make the transition as swift as
+	// possible and I can prove that at least one cycle will be lost in
+	// processor operation. Thus...
+	tmu->TCNT = new_constant - 1;
+	tmu->TCOR = new_constant;
+}

src/timer/timer_get.c

@@ -1,25 +0,0 @@
-#include <internals/timer.h>
-#include <mpu.h>
-
-/*
-	timer_get()
-	Returns the timer and TSTR register addresses.
-*/
-void timer_get(int timer, volatile struct mod_tmu **tmu,
-	volatile unsigned char **tstr)
-{
-	// Using SH7705 information for SH-3-based MPUs.
-	if(isSH3())
-	{
-		if(tstr) *tstr = (volatile unsigned char *)0xfffffe92;
-		if(tmu) *tmu = (volatile struct mod_tmu *)
-			(0xfffffe94 + 12 * timer);
-	}
-	// Assuming SH7305 by default.
-	else
-	{
-		if(tstr) *tstr = (volatile unsigned char *)0xa4490004;
-		if(tmu) *tmu = (volatile struct mod_tmu *)
-			(0xa4490008 + 12 * timer);
-	}
-}

src/timer/timer_interrupt.c

@@ -1,41 +0,0 @@
-#include <internals/timer.h>
-#include <timer.h>
-
-#include <stddef.h>
-
-struct Timer timers[3] = {
-	{ .callback = NULL, .data = NULL, .repeats = 0 },
-	{ .callback = NULL, .data = NULL, .repeats = 0 },
-	{ .callback = NULL, .data = NULL, .repeats = 0 },
-};
-
-/*
-	timer_interrupt()
-	Handles the interrupt for the given timer.
-*/
-void timer_interrupt(int timer)
-{
-	volatile struct mod_tmu *tmu;
-	timer_get(timer, &tmu, NULL);
-
-	tmu->TCR.UNF = 0;
-
-	if(timers[timer].callback)
-	{
-		if(timers[timer].data)
-		{
-			void (*fun)(void *data) = timers[timer].callback;
-			fun(timers[timer].data);
-		}
-		else
-		{
-			void (*fun)(void) = timers[timer].callback;
-			fun();
-		}
-	}
-
-	// Reducing the number of repetitions left, if not infinite.
-	if(!timers[timer].repeats) return;
-	if(timers[timer].repeats == 1) timer_stop(timer);
-	else timers[timer].repeats--;
-}

src/timer/timer_reload.c

@@ -1,32 +0,0 @@
-#include <internals/timer.h>
-#include <timer.h>
-
-/*
-	timer_reload()
-	Reloads the given timer with the supplied constant. Starts the timer if
-	it was stopped.
-*/
-void timer_reload(int timer, int new_delay_or_frequency, enum ClockUnit unit)
-{
-	timer_reload2(timer, clock_setting(new_delay_or_frequency, unit));
-}
-
-/*
-	timer_reload2()
-	Same as timer_reload(), but again uses the native clock count. The
-	prescaler may not be changed.
-*/
-void timer_reload2(int timer, int new_delay)
-{
-	volatile struct mod_tmu *tmu;
-	volatile unsigned char *tstr;
-	int byte = (1 << timer);
-	timer_get(timer, &tmu, &tstr);
-
-	// Setting the constant and the delay.
-	tmu->TCOR = new_delay;
-	tmu->TCNT = new_delay;
-
-	// Starting the timer.
-	*tstr |= byte;
-}

src/timer/timer_start.c

@@ -1,48 +0,0 @@
-#include <internals/timer.h>
-#include <timer.h>
-
-/*
-	timer_start2()
-	Configures and starts a time using a clock count and a prescaler.
-*/
-void timer_start2(int timer, int delay, int prescaler, void *callback,
-	void *data, int repeats)
-{
-	volatile struct mod_tmu *tmu;
-	volatile unsigned char *tstr;
-	int byte = (1 << timer);
-
-	timer_get(timer, &tmu, &tstr);
-
-	// Loading the counter, the constant and the prescaler/
-	tmu->TCOR = delay;
-	tmu->TCNT = delay;
-	tmu->TCR.TPSC = prescaler;
-
-	// Resetting underflow flag and enabling interruptions.
-	tmu->TCR.UNF = 0;
-	tmu->TCR.UNIE = 1;
-
-	// Counting on rising edge (ignored on SH7305).
-	tmu->TCR.CKEG = 0;
-
-	// Loading the structure information.
-	timers[timer].callback	= callback;
-	timers[timer].data	= data;
-	timers[timer].repeats	= repeats;
-
-	// Starting the timer.
-	*tstr |= byte;
-}
-
-/*
-	timer_start()
-	Configures and starts a timer using a delay, or a frequency, and the
-	associated unit.
-*/
-void timer_start(int timer, int delay, enum ClockUnit unit, void *callback,
-	void *data, int repeats)
-{
-	timer_start2(timer, clock_setting(delay, unit), TIMER_Po_4, callback,
-		data, repeats);
-}

src/timer/timer_stop.c

@@ -1,18 +0,0 @@
-#include <internals/timer.h>
-#include <timer.h>
-
-#include <stddef.h>
-
-/*
-	timer_stop()
-	Stops the given timer. This function may be called even if the timer is
-	not running.
-*/
-void timer_stop(int timer)
-{
-	volatile unsigned char *tstr;
-	int byte = (1 << timer);
-
-	timer_get(timer, NULL, &tstr);
-	*tstr &= ~byte;
-}

src/timer/virtual_timers.c

@@ -0,0 +1,223 @@
+#include <timer.h>
+#include <clock.h>
+#include <internals/timer.h>
+#include <modules/timer.h>
+
+//---
+//	Public API
+//---
+
+timer_t vtimers[TIMER_SLOTS] = { 0 };
+
+/*
+	timer_create()
+	Creates a virtual timer and configures its delay and repetition count.
+*/
+timer_t *timer_create(int ms_delay, int repeats)
+{
+	if(ms_delay <= 0) return NULL;
+	timer_t *timer = vtimers;
+
+	// Finding an available virtual slot.
+	while(timer < vtimers + TIMER_SLOTS && timer->used) timer++;
+	if(timer >= vtimers + TIMER_SLOTS) return NULL;
+
+	timer->ms_delay		= ms_delay;
+	timer->ms_elapsed	= 0;
+	timer->repeats_left	= repeats;
+
+	timer->used		= 1;
+	timer->active		= 0;
+	timer->virtual		= 1;
+	timer->vsupport		= 0;
+	timer->events		= 0;
+
+	timer->callback		= NULL;
+	timer->argument		= NULL;
+
+	return timer;
+}
+
+/*
+	timer_destroy()
+	Destroys a virtual timer. This virtual timer pointer becomes invalid
+	and should not be used anymore.
+*/
+void timer_destroy(timer_t *timer)
+{
+	timer->events	= 0;
+	timer->active	= 0;
+	timer->used	= 0;
+
+	vtimer_updateAll();
+}
+
+
+
+//---
+//	Virtual timers management
+//---
+
+static int current_delay = 0;
+static uint32_t current_constant = 0;
+
+/*
+	vtimer_interrupt()
+	Interrupt handling subsystem for the virtual timers.
+*/
+void vtimer_interrupt(void)
+{
+	// Do we need to recompute the hardware support frequency?
+	int recalc = 0;
+
+	// No timer is running.
+	if(!current_delay) return;
+
+	// Update them all and call the required callbacks. Stop the ones that
+	// have been running for long enough.
+	for(timer_t *timer = vtimers; timer < vtimers + TIMER_SLOTS; timer++)
+	if(timer->used)
+	{
+		timer->ms_elapsed += current_delay;
+
+		// This should happen only once but in case there is a problem,
+		// this loop will ensure that at least the correct amount of
+		// callbacks is executed.
+		// We could divide but it would be slower.
+		while(timer->ms_elapsed >= timer->ms_delay)
+		{
+			// We don't call the callbacks now because we may need
+			// to update the timer frequency later and we want to
+			// get there asap.
+			timer->events++;
+			timer->ms_elapsed -= timer->ms_delay;
+		}
+
+		// We would need to stop one virtual timer.
+		if(timer->repeats_left > 0 && timer->repeats_left <=
+			timer->events) recalc = 1;
+	}
+
+	if(recalc) vtimer_updateAll();
+
+	for(timer_t *timer = vtimers; timer < vtimers + TIMER_SLOTS; timer++)
+	if(timer->used)
+	{
+		while(timer->active && timer->events)
+		{
+			timer_callback_event(timer);
+			timer->events--;
+		}
+		timer->used = timer->active;
+	}
+}
+
+/*
+	vtimer_update()
+	Swiftly updates the hardware support counter and constant to keep up
+	with new kinds of timers being added while disturbing the counting flow
+	as little as possible.
+*/
+static void vtimer_update(int new_delay)
+{
+	volatile mod_tmu_timer_t *tmu = TMU.timers[timer_virtual];
+	timer_t *timer = &htimers[timer_virtual];
+
+	if(new_delay == current_delay) return;
+
+	if(!new_delay)
+	{
+		current_delay		= 0;
+		current_constant	= 0;
+
+		// At this point the virtual support timer was running and has
+		// been stopped, thus the hardware timer structure is filled
+		// properly so we can use this function.
+		timer_stop(timer);
+		return;
+	}
+	uint32_t new_constant = clock_setting(new_delay, Clock_ms);
+
+	// The transition needs to be as smooth as possible. We have probably
+	// spent a lot of time calculating this new GCD delay so we want to
+	// take into consideration the current value of the timer counter.
+	// The -1 is here to take into account the time between reading and
+	// writing the new constant (~10 I_phi cycles thus usually 5 P_phi
+	// cycles; given this timer runs on P_phi / 4 this makes 1 unit).
+	// Here we suppose that the new TCNT is positive, i.e that the update
+	// happened in less than 1 ms. This is reasonable as long as this
+	// happens *before* calling callbacks.
+	tmu->TCNT = new_constant - (current_constant - tmu->TCNT - 1);
+	tmu->TCOR = new_constant;
+
+	if(!current_delay)
+	{
+		// Ups, we've been using a random counter; the timer's not
+		// running.
+		tmu->TCNT		= tmu->TCOR;
+		// Set it up then.
+		tmu->TCR.TPSC		= timer_Po_4;
+		tmu->TCR.UNF		= 0;
+		tmu->TCR.UNIE		= 1;
+		tmu->TCR.CKEG		= 0;
+		// Tell them that the virtual timer support is running there.
+		timer->used		= 1;
+		timer->active		= 0;
+		timer->virtual		= 0;
+		timer->vsupport		= 1;
+		timer->events		= 0;
+		// And let's roll!
+		timer_start(timer);
+	}
+
+	current_delay = new_delay;
+	current_constant = new_constant;
+}
+
+/*
+	gcd()
+	Well, the Euclidean algorithm. That's a O(ln(a)) & O(ln(b)) FWIW.
+*/
+static int gcd(int a, int b)
+{
+	while(b)
+	{
+		int r = a % b;
+		a = b;
+		b = r;
+	}
+
+	return a;
+}
+
+/*
+	vtimer_updateOne()
+	Update the virtual timer hardware support timer, knowing that a virtual
+	timer with the given delay has been started.
+*/
+void vtimer_updateOne(int additional_delay)
+{
+	vtimer_update(gcd(current_delay, additional_delay));
+}
+
+/*
+	vtimer_updateAll()
+	Updates the virtual timer hardware support after computing the GCD of
+	all virtual timers delays. This computation is rather long (especially
+	this modulo can afaik only be achieved using division on SuperH and
+	it's a 70-cycle operation) so it should be avoided when possible.
+*/
+
+void vtimer_updateAll(void)
+{
+	int gcd_delay = 0;
+
+	for(timer_t *timer = vtimers; timer < vtimers + TIMER_SLOTS; timer++)
+	if(timer->used && timer->active && (timer->repeats_left <= 0 ||
+		timer->repeats_left > timer->events))
+	{
+		gcd_delay = gcd(gcd_delay, timer->ms_delay);
+	}
+
+	vtimer_update(gcd_delay);
+}