>-----Original Message-----
>From: piclist-bounces@mit.edu [mailto:piclist-bounces@mit.edu] 
>Sent: 28 July 2005 15:59
>To: piclist@mit.edu
>Subject: Re: [PIC] [OT] Cost of dev tools complaint. (was Free 
>C Compiler
>
>
>> Is anyone aware of a reason for the lack of OSS for the PIC (in
>> particular PIC18)? Is there another processor that's taken 
>most of the 
>> interest of the OSS community, and has better OSS tools?
>
>The AVR seems to be well supported by the OSS community.
>
>Basically if the people who use the chips want to write 
>support for it, the support will be there.

FWIW I am working on a project using the AVR GCC compiler, and having used HiTech's compiler for both the 14 and 16bit PIC's for the last 5 years or so, I was surprised to see how poor the optimisation of the GCC compiler was in a few areas e.g. testing a bit in 32 bit value produced numerous (ISTR ~15) instructions when a single bit test instruction could have been used, and binary weighted multplies/divides are not optimised well.

GCC lacks intrinsic support for Harvard memory architectures, i.e. accessing data in program memory has to be performed through a macro.  The HiTech compiler automaticly puts 'const' objects in program memory and you can access such objects directly through a pointer, no macros etc.  You can even access both data and (most of) program memory through the same pointer which makes string handling functions so much simpler.

GCC lacks suppport for bit variables, meaning writing to pins requires using bit masks.  Worse still an entire byte is used for each boolean variable (they do not get packed).


On the plus side, the value for money cannot be beaten, and most flaws would not concern a hobbiest.

Regards

Mike

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