[ECOS] Question CYGNUM_KERNEL_THREADS_DATA_MAX?
Thu Jan 30 06:26:00 GMT 2003
Patrick Doyle wrote:
>>>Thats what im relying on. 1<<32 should be 0 on most processors. If so,
>>>it all works out correct. But its not something i would trust unless
>>>it was written down in some standard and gcc actually implements that
I just looked at the standard to be absolutely sure about this and it
says: "If the value of the right operand is negative or is greater than or
equal to the width of the promoted left operand, the behavior is undefined."
> Wandering in here very late in the game, I am wondering why you don't just
> mask the result of the shift with 0xFFFFFFFFu whereever you use it. On
> 32-bit machines, the optimizer will (presumably) ignore the NOP mask, and on
> other machines, the result will be 0 as you desire.
Well that's true, although it would be nice if we allowed it to work with
64-bit addresses in future (difficult with the CDL constraint, but whatever).
The following should do it:
cyg_ucount32 Cyg_Thread::thread_data_map = (~CYGNUM_KERNEL_THREADS_DATA_ALL) &
Icky, but avoids overflow and gets compiled to a constant by the compiler
(obviously otherwise it wouldn't compile as an initializer!).
I'll check this in.
eCosCentric http://www.eCosCentric.com/ <info@eCosCentric.com>
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