11.12.2013 12:28, Sven Barth пишет:
Am 11.12.2013 08:43, schrieb Michael Ring:
The strb command seems to be the problem, documentation from STM states:
Each I/O port bit is freely programmable, however the I/O port registers have
to be accessed as
32-bit words (half-word or byte accesses are not allowed).
So, is there some way to make the bitset operations word-aligned?
Better say 32-bit aligned to avoid confusion. Words in Pascal are 16-bit
although I know that you
are talking about the CPUs word size...
Are there any good reasons for not doing so?
What when you really have a byte that you want ot access? Then using 32-bit
writes/reads could(*)
result in unnecessary cycles.
* I don't know about ARM especially, but I know that for e.g. the m68k a 32-bit
store is more
expensive than a 16-bit or 8-bit store
That said I don't have a solution for your specific problem except by doing it
by hand.
Maybe size of memory access must be guided by size of record? For ARM the record will be 32-bit, and
for m68k it can be 8 or 16-bit.
Regards,
Sergei
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