15 Jun
2011
15 Jun
'11
2:42 p.m.
On 15/06/11 22:04, Wolfgang Denk wrote:
Dear Aneesh V,
In message 4DF89102.9040508@ti.com you wrote:
Will you accept something like this?
a_val = (reg & a_mask) >> a_shift;
Yes, of course (that's what seems most natural to me).
Me too - The code is obvious - the desired value is being masked out of a larger composite value and then shifted right to bit 0
And to set the value then you have:
reg &= ~a_mask; /* Clear a_val */ reg |= (a_val << a_shift) & a_mask; /* Set new a_val */
AND'ing with a_mask is required to prevent accidental clobbering when a_val is out-of-range. May give undesirable results by setting an illegal a_val, but at least you don't clobber unrelated bit fields
Regards,
Graeme