Re: [avr-libc-dev] RFC: avr/bits.h

[Dave Hylands]

Hi Bob,

> I wanted to do a test case for using bit_XXX on longs to see if it does the
> right thing, and wrote the following test case.  However the results to me
> are puzzling, they look down right broken.  What is going on here?:

Part of the problem is that bit_set wants a bit number, and you're
providing a bit mask (I was fooled until I looked at the preprocessor
output).

So 

    bit_set( shorttest_u16, BIT(4) ); 

should really be 

    bit_set( shorttest_u16, 4 );

Then it doesn't fail until

   bit_set( longtest_u32, 16 );

which happens because

    1

is an int, whereas

    1L

is a longint. Since ints are 16 bits wide 1 << 16 gives the warning,
while 1L << 16 works fine.

-- 
Dave Hylands
Vancouver, BC, Canada
http://www.DaveHylands.com/