Revised Specification - Implementation details

{
	return CONFIG_SYS_TICK_PER_MS;
}
{
	return CONFIG_SYS_TICK_PER_MS;
}
DENX Software Engineering GmbH,     MD: Wolfgang Denk & Detlev Zundel
HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
Phone: (+49)-8142-66989-10 Fax: (+49)-8142-66989-80 Email: wd at denx.de
There you go man, Keep as cool as you can. It riles them  to  believe
that you perceive the web they weave. Keep on being free!
{
	return CONFIG_SYS_TICK_PER_MS;
}
DENX Software Engineering GmbH,     MD: Wolfgang Denk & Detlev Zundel
HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
Phone: (+49)-8142-66989-10 Fax: (+49)-8142-66989-80 Email: wd at denx.de
"There are three principal ways to lose money: wine, women,  and  en-
gineers.  While  the first two are more pleasant, the third is by far
the more certain."                      -- Baron Rothschild, ca. 1800
DENX Software Engineering GmbH,     MD: Wolfgang Denk & Detlev Zundel
HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
Phone: (+49)-8142-66989-10 Fax: (+49)-8142-66989-80 Email: wd at denx.de
Behind every great man, there is a woman -- urging him on.
	-- Harry Mudd, "I, Mudd", stardate 4513.3
DENX Software Engineering GmbH,     MD: Wolfgang Denk & Detlev Zundel
HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
Phone: (+49)-8142-66989-10 Fax: (+49)-8142-66989-80 Email: wd at denx.de
As of 1992, they're called European Economic Community fries.
DENX Software Engineering GmbH,     MD: Wolfgang Denk & Detlev Zundel
HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
Phone: (+49)-8142-66989-10 Fax: (+49)-8142-66989-80 Email: wd at denx.de
Any sufficiently advanced technology is indistinguishable from magic.
                                                   - Arthur C. Clarke
{
        return CONFIG_SYS_TICK_PER_MS;
}
{
        return CONFIG_SYS_TICK_PER_MS;
}
{
	static u64 last_hw_tick_count;
	static u64 last_sw_tick_count;

	/* Now for the platform specific stuff - Read hardware tick counter */
	u64 current_hw_tick_count = /* Read hw registers etc */

	/* Deal with hardware weirdness - errata, stupid hw engineers etc */

	u64 elapsed_ticks = current_hw_tick_count - last_hw_tick_count;
	last_sw_tick_count += elapsed_ticks;

	return last_sw_tick_count;
}
{
	static u64 last_hw_tick_count;
	static u64 last_sw_tick_count;

	/* Now for the platform specific stuff - Read hardware tick counter */
	u64 current_hw_tick_count = /* Read hw registers etc */

	/* Deal with hardware weirdness - errata, stupid hw engineers etc */

	u64 elapsed_ticks = current_hw_tick_count - last_hw_tick_count;
	last_sw_tick_count += elapsed_ticks;

	return last_sw_tick_count;
}
    if (gd->timer_counts_down)
     count.lsb = gd->lsb_max_value - count.lsb;
      if (gd->lsb_max_value > 0 )
         count.u64 = count.msb * gd->lsb_max_value + count.lsb;
DENX Software Engineering GmbH,     MD: Wolfgang Denk & Detlev Zundel
HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
Phone: (+49)-8142-66989-10 Fax: (+49)-8142-66989-80 Email: wd at denx.de
A witty saying proves nothing, but saying  something  pointless  gets
people's attention.
DENX Software Engineering GmbH,     MD: Wolfgang Denk & Detlev Zundel
HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
Phone: (+49)-8142-66989-10 Fax: (+49)-8142-66989-80 Email: wd at denx.de
If the odds are a million to one against something occuring,  chances
are 50-50 it will.
	do {
		upper  = timebase_upper;
		lower  = timebase_lower;
	} while (upper != timebase_upper);
DENX Software Engineering GmbH,     MD: Wolfgang Denk & Detlev Zundel
HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
Phone: (+49)-8142-66989-10 Fax: (+49)-8142-66989-80 Email: wd at denx.de
You can only live once, but if you do it right, once is enough.
DENX Software Engineering GmbH,     MD: Wolfgang Denk & Detlev Zundel
HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
Phone: (+49)-8142-66989-10 Fax: (+49)-8142-66989-80 Email: wd at denx.de
 The software required `Windows 95 or better', so I installed Linux.
DENX Software Engineering GmbH,     MD: Wolfgang Denk & Detlev Zundel
HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
Phone: (+49)-8142-66989-10 Fax: (+49)-8142-66989-80 Email: wd at denx.de
The use of Microsoft crippleware systems is a sin that  carries  with
it its own punishment.
         -- Tom Christiansen in <[email protected]>
DENX Software Engineering GmbH,     MD: Wolfgang Denk & Detlev Zundel
HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
Phone: (+49)-8142-66989-10 Fax: (+49)-8142-66989-80 Email: wd at denx.de
"Plan to throw one away. You will anyway."
                              - Fred Brooks, "The Mythical Man Month"
	for (;;) {
		u32 t = get_time();

		printf("t=%ul\n", t);
	}
DENX Software Engineering GmbH,     MD: Wolfgang Denk & Detlev Zundel
HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
Phone: (+49)-8142-66989-10 Fax: (+49)-8142-66989-80 Email: wd at denx.de
A girl with a future avoids the man with a past.
                                   -- Evan Esar, "The Humor of Humor"
        for (;;) {
                u32t = get_time();
                printf("t=%ul\n", t);
        }
DENX Software Engineering GmbH,     MD: Wolfgang Denk & Detlev Zundel
HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
Phone: (+49)-8142-66989-10 Fax: (+49)-8142-66989-80 Email: wd at denx.de
Extended Epstein-Heisenberg Principle: In an R & D orbit, only  2  of
the  existing 3 parameters can be defined simultaneously. The parame-
ters are: task, time and resources ($).
DENX Software Engineering GmbH,     MD: Wolfgang Denk & Detlev Zundel
HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
Phone: (+49)-8142-66989-10 Fax: (+49)-8142-66989-80 Email: wd at denx.de
"...this does not mean that some of us should not want, in  a  rather
dispassionate sort of way, to put a bullet through csh's head."
                   - Larry Wall in <[email protected]>
	do {
		upper  = timebase_upper;
		lower  = timebase_lower;
	} while (upper != timebase_upper);
{
	if (base != 0) {
		if (timer - base < (CONFIG_MIN_TIMER_RESOLUTION * 2))
			return 0;
		else
			return timer - base - CONFIG_MIN_TIMER_RESOLUTION;
	} else {
		return timer;
	}
}
{
	if (base != 0) {
		if (timer - base<  (CONFIG_MIN_TIMER_RESOLUTION * 2))
			return 0;
		else
			return timer - base - CONFIG_MIN_TIMER_RESOLUTION;
	} else {
		return timer;
	}
}
{
    if (base != 0) {
        if (timer - base<  (CONFIG_MIN_TIMER_RESOLUTION * 2))
            return 0;
        else
            return timer - base - CONFIG_MIN_TIMER_RESOLUTION;
    } else {
        return timer;
    }
}
	get_timer(0) @ 109ms returns 100

	end_time = 110

	end_time will be reached in 1ms, not 10 as expected
	end_time = end_time(timeout);

	while (get_timer() < end_time) {
		/* Do Stuff */
	}
{
	if (base != 0) {
		if (timer - base<  (CONFIG_MIN_TIMER_RESOLUTION * 2))
			return 0;
		else
			return timer - base - CONFIG_MIN_TIMER_RESOLUTION;
	} else {
		return timer;
	}
}
DENX Software Engineering GmbH,     MD: Wolfgang Denk & Detlev Zundel
HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
Phone: (+49)-8142-66989-10 Fax: (+49)-8142-66989-80 Email: wd at denx.de
Q:  How many DEC repairman does it take to fix a flat?
A:  Five; four to hold the car up and one to swap tires.
Q:  How long does it take?
A:  It's indeterminate.  It will depend upon how many flats they've
    brought with them.
Q:  What happens if you've got TWO flats?
A:  They replace your generator.
	while (test_for_event() == 0) {
		if (--loops <= 0)
			handle_timeout();

		udelay(500000);	/delay 500 millisecond */
	}
	while (test_for_event() == 0) {
		if (--loops <= 0)
			handle_timeout();

		udelay(100);
	}
   	start = get_timer(0);
	while (test_for_event() == 0) {
		now = get_timer(0);
		if ((now - start) > timeout)
			handle_timeout();

		udelay(100);
	}
	start = get_timer(0);

	do_something_complicated();

	now = get_timer(0);

	printf("execution time: %ld millisec\n", now - start);
	/*
	 * Everybody uses a 1 millisecond interval, 
	#ifdef CONFIG_NIOS2
	static inline u32 timer_interval_size(void) { return 10; }
	#else
	static inline u32 timer_interval_size(void) { return 1; }
	#endif

	u32 delta_timer(u32 from, u32 to)
	{
		u32 delta = to - from;

		if (delta < timer_interval_size())
			return 0;

		return detla - timer_interval_size();
	}
	/*
	 * round - used to control rounding:
	 * <0 : round down, return time that has passed AT LEAST
	 * =0 : don't round, provide raw time difference
	 * >0 : round up, return time that has passed AT MOST
	 */
	 u32 delta_timer(u32 from, u32 to, int round)
	 {
		u32 delta = to - from;

		if (round == 0)	/* raw result, no rounding*/
			return delta;

		if (round > 0)	/* round up */
			return delta + timer_interval_size();

		/* round down */
		if (delta < timer_interval_size())
			return 0;

		return delta - timer_interval_size();
	}
   	start = get_timer(0);
	while (test_for_event() == 0) {
		now = get_timer(0);

		if (delta_timer(start, now) > timeout)
			handle_timeout();

		udelay(100);
	}
DENX Software Engineering GmbH,     MD: Wolfgang Denk & Detlev Zundel
HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
Phone: (+49)-8142-66989-10 Fax: (+49)-8142-66989-80 Email: wd at denx.de
"Beware of bugs in the above code; I have only proved it correct, not
tried it."                                             - Donald Knuth
	while (test_for_event() == 0) {
		if (--loops <= 0)
			handle_timeout();

		udelay(500000);	/delay 500 millisecond */
	}
	while (test_for_event() == 0) {
		if (--loops <= 0)
			handle_timeout();

		udelay(100);
	}
   	u32 start,now;
	u32 timeout = 5 * CONFIG_SYS_HZ; /* timeout after 5 seconds */

   	start = get_timer(0);

	while (test_for_event() == 0) {
		now = get_timer(0);
		if ((now - start) > timeout)
			handle_timeout();

		udelay(100);
	}

   Here the loop overhead caused by short delay which may result in a
   high number of calls to test_for_event() gets eliminated because
   the time reference is independet of the delay.
   These are usually used to measure the time needed to perform some
   specific actions, for example like this:

   	u32 start, now;

	start = get_timer(0);

	do_something_complicated();

	now = get_timer(0);

	printf("execution time: %ld millisec\n", now - start);
	do_something();
	udelay(500);
	/* Operation has finished - Keep going  */

	OR

	u32 start;

	do_something();

	start = get_timer(0);
	while (get_timer(start) < 500)
		;
	/* Operation has finished - Keep going  */
	/*
	 * Everybody uses a 1 millisecond interval, 
	#ifdef CONFIG_NIOS2
	static inline u32 timer_interval_size(void) { return 10; }
	#else
	static inline u32 timer_interval_size(void) { return 1; }
	#endif

	u32 delta_timer(u32 from, u32 to)
	{
		u32 delta = to - from;

		if (delta < timer_interval_size())
			return 0;

		return detla - timer_interval_size();
	}
	/*
	 * round - used to control rounding:
	 * <0 : round down, return time that has passed AT LEAST
	 * =0 : don't round, provide raw time difference
	 * >0 : round up, return time that has passed AT MOST
	 */
	 u32 delta_timer(u32 from, u32 to, int round)
	 {
		u32 delta = to - from;

		if (round == 0)	/* raw result, no rounding*/
			return delta;

		if (round > 0)	/* round up */
			return delta + timer_interval_size();

		/* round down */
		if (delta < timer_interval_size())
			return 0;

		return delta - timer_interval_size();
	}
   	u32 start,now;
	u32 timeout = 5 * CONFIG_SYS_HZ; /* timeout after 5 seconds */

   	start = get_timer(0);

	while (test_for_event() == 0) {
		now = get_timer(0);

		if (delta_timer(start, now) > timeout)
			handle_timeout();

		udelay(100);
	}
	u32 start = get_current_ms();

	while (test_for_event() == 0) {
		if (time_elapsed(start, timeout))
			handle_timeout();

		udelay(100);
	}
	while (test_for_event() == 0) {
		now = get_timer(0);
		if ((now - start) > timeout)
			handle_timeout();

		udelay(100);
	}
	start = get_timer(0);

	do_something_complicated();

	now = get_timer(0);

	printf("execution time: %ld millisec\n", now - start);
DENX Software Engineering GmbH,     MD: Wolfgang Denk & Detlev Zundel
HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
Phone: (+49)-8142-66989-10 Fax: (+49)-8142-66989-80 Email: wd at denx.de
"I find this a nice feature but it is not according to  the  documen-
tation. Or is it a BUG?"   "Let's call it an accidental feature. :-)"
                       - Larry Wall in <[email protected]>
	while (test_for_event() == 0) {
		now = get_timer(0);
		if ((now - start) > timeout)
			handle_timeout();

		udelay(100);
	}
	start = get_timer(0);

	do_something_complicated();

	now = get_timer(0);
	printf("execution time: %ld millisec\n", now - start);
    ...
	u32 start = get_timer();

	while (!timer_expired(start, timeout))
		...
    ...
	u32 start = get_timer();

	while (!timer_expired(start, timeout))
		...
    ...
        u32 start = get_timer();

        while (!timer_expired(start, timeout))
                ...
        u32 start = get_timer();

        while (!timer_expired(start, timeout))
                ...
    ..
	u32 stop = get_current_ms() + 1234;
	u64 start = get_current_tick();
	... do something ...
	u32 duration = ticks_to_ms(get_current_tick() - start);
        u32 start = get_timer();

        while (!timer_expired(start, timeout))
                ...
    ..
	u32 stop = get_current_ms() + 1234;
	u64 start = get_current_tick();
	... do something ...
	u32 duration = ticks_to_ms(get_current_tick() - start);
DENX Software Engineering GmbH,     MD: Wolfgang Denk & Detlev Zundel
HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
Phone: (+49)-8142-66989-10 Fax: (+49)-8142-66989-80 Email: wd at denx.de
"Bureaucracy is the enemy of innovation."
       - Mark Shepherd, former President and CEO of Texas Instruments
DENX Software Engineering GmbH,     MD: Wolfgang Denk & Detlev Zundel
HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
Phone: (+49)-8142-66989-10 Fax: (+49)-8142-66989-80 Email: wd at denx.de
"UNIX was not designed to stop you from doing stupid things,  because
that would also stop you from doing clever things."       - Doug Gwyn
DENX Software Engineering GmbH,     MD: Wolfgang Denk & Detlev Zundel
HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
Phone: (+49)-8142-66989-10 Fax: (+49)-8142-66989-80 Email: [email protected]
Just because your doctor has a name for your condition  doesn't  mean
he knows what it is.
DENX Software Engineering GmbH,     MD: Wolfgang Denk & Detlev Zundel
HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
Phone: (+49)-8142-66989-10 Fax: (+49)-8142-66989-80 Email: wd at denx.de
core error - bus dumped
DENX Software Engineering GmbH,     MD: Wolfgang Denk & Detlev Zundel
HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
Phone: (+49)-8142-66989-10 Fax: (+49)-8142-66989-80 Email: wd at denx.de
I think there's a world market for about five computers.
         -- attr. Thomas J. Watson (Chairman of the Board, IBM), 1943
	}
   	u32 start,now;
	u32 timeout = 5 * CONFIG_SYS_HZ; /* timeout after 5 seconds */

   	start = get_timer(0);
	start = time_ms_now();
	while (test_for_event() == 0) {
		now = get_timer(0);

		if (delta_timer(start, now) > timeout)
			handle_timeout();

		udelay(100);
	}
      }
	ulStartJiffies = time_ms_now();
	while (time_ms_delta_min(ulStartJiffies, time_ms_now())
			< NS7520_MII_NEG_DELAY) {
	ulStartJiffies = time_ms_now();
	while (time_min_ms_since(ulStartJiffies) < NS7520_MII_NEG_DELAY) {
	start_ms = time_ms_now();
	while (time_min_ms_since(start_ms) < NS7520_MII_NEG_DELAY) {
{
	u32 start = time_now_us();

	while(time_since_us(start) < delay)
		;
}