16 May
2011
16 May
'11
5:52 p.m.
Dear Simon Glass,
In message BANLkTin6o4OEp7aBfCsxpt=z5oZToxVE2g@mail.gmail.com you wrote:
I believe the problem here is the read/modify/write behaviour which is not well-defined in C. One ends up using volatile to ensure the right behaviour, and then this doesn't necessarily work either. Where one write must happen
volatile does not help anything here. You MUST always make sure to use proper I/O accessors. Even in ARM code this has become mandatory by now, even if older ARM cores and compilers have been forgiving enough for a long time.
Perhaps in newer compilers bitfield semantics have been improved?
Bitfields have always been a mess, and should be avoided like hell.
Best regards,
Wolfgang Denk
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