Dear Dirk Behme,
In message <1362387637-32334-1-git-send-email-dirk.be...@de.bosch.com> you
wrote:
> From: Dirk Behme <dirk.be...@de.bosch.com>
>
> Several ARM timer implementations use gd->arch.tbl to record the
> absolute tick count of 32-bit counters, including timer overflows.
> For example arch/arm/imx-common/timer.c does:
>
> ulong lastinc;
> ulong now = counter value;
> if (no overflow) {
> ...
> } else { /* counter overflow */
> gd->arch.tbl += (0xFFFFFFFF - lastinc) + now;
> }
> lastinc = now;
>
> As we use a 32-bit counter and the two ulong (32-bit) variables 'lastinc'
> and 'now' here, gd->arch.tbl should be long long (64-bit) to not overflow
> at the same time, too.
I think this is wrong.
"tbl" means "time base, lower 32 bits" and is complemented by "tbu"
(time base, upper 32 bits) to form a 64 bit time base counter.
If you need the full 64 bit precision, then please either maintain the
carry manually, or use a proper union or similar.
Best regards,
Wolfgang Denk
--
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: w...@denx.de
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it is, pockets the watch, and sends you a bill for it.
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