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Date: Wed, 09 Feb 2011 10:49:37 -0500
From: Hyman Rosen <hyrosen@mail.com>
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Subject: Re: How do I write directly to a memory address?
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Date: 2011-02-09T10:49:37-05:00
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On 2/8/2011 9:33 PM, Adam Beneschan wrote:
>  Dmitry asks, "How do you set the third
> bit?", and you say, "Well, if the third bit is a Ready bit in a
> hardware I/O register, I'd define a struct with bit components [yes, I
> think C has those] and just assign 1 to the component, which would be
> more readable than using a mask."

This can be considerably more complicated depending on
the hardware and the compiler; you are trying to assign
to a single bit, but the compiler may do this by reading
an entire word, setting the bit in the result, and
assigning the entire word back. That could have dire
effects if writing adjacent bits does something.