Le 23/05/2011 19:30, J. William Campbell a écrit : >> Did you have a look at the PowerPC implementation? I'd like to see >> this used as reference.
> I have looked at it as a reference. However, there is one disadvantage > in using the PPC code as a reference. It has a 64 bit timestamp. Many > systems do not have a 64 bit timestamp, but rather a 32 bit timestamp. > It is possible to extend the 32 bit timestamp to a 64 bit timestamp if > get_timer is called often enough that there will only be a single > rollover of the bottom 32 bits between uses. However, if that condition > is met, there is no need to extend the timer to 64 bits. Well, there is one: making sure that drivers do not need to know if timestamps are 32 or 64 bits, or even what resolution they are. Granted, you could define a timestamp_t type to be either u32 or u64 depending on the actual timestamp width, so that the driver would not need to know the details; but extending u32 to u64, or subtracting two u64 values, are not so much of an effort, and that would mean a single API. Amicalement, -- Albert. _______________________________________________ U-Boot mailing list U-Boot@lists.denx.de http://lists.denx.de/mailman/listinfo/u-boot