[ECOS] Re: newbie qn about eCos integral types

Grant Edwards grante@visi.com
Wed Oct 18 23:30:00 GMT 2006


In gmane.os.ecos.general, you wrote:

>> On both processors cyg_uint16 is exactly 16 bits and cyg_uint32 is
>> exactly 32 bits. Hence those data types can be used reliably for
>> describing hardware, for defining network protocols, etc.
>>
>> However cyg_ucount16 is 16 bits on the 16-bit processor and 32
>> bits on the 32-bit processor. In both cases cyg_ucount16 is
>> the most efficient data type that provides at least the
>> specified number of bits.

IOW, it's a different spelling of the C<mumble> standard types
int_fastNN_t and uint_fastNN_t.

> Sounds like a good application for "int" or "unsigned int".

There are (now) actually standard C types for the usage in
question, but I don't think gcc implemented them back in the
early days of eCos.  Maybe they weren't even in the standards
back them -- I forget.

> Having a type alias for a 32-bit integer with "16" in its name
> is pretty confusing, leading to questions like this.

You'll have to have chat with the C standards people: the
standard types *_fast16_t are probably 32 bits on a lot of
platforms.

-- 
Grant Edwards                   grante             Yow!  ... PENGUINS are
                                  at               floating by...
                               visi.com            

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