>-----Original Message-----
>From: piclist-bounces@mit.edu [mailto:piclist-bounces@mit.edu] 
>Sent: 15 February 2005 15:27
>To: Microcontroller discussion list - Public.
>Subject: RE: [PIC] Bug in Microchip mcc18 std library?
>
>
>> In Hitech the only type of pointer that can point to both data and 
>> program memory are pointers to const data types.  Are you 
>saying it's 
>> preferable to have two different functions to deal with pointers to 
>> data/program memory rather than one function that can work with 
>> either? e.g. puts() which is used by printf etc.  As sson as you
>> start splitting
>> things up like this the compiler moves away from ANSI 
>> compatibility and
>> you have to add all sorts of kludges to get things working.
>> 
>
>The ANSI standard C is designed around an architecture which 
>makes no distinction in memory between data and code space; 
>the PIC isn't like that. Whilst it's possible to create an 
>ANSI standard compiler for a PIC, the architectural quirks, 
>IMO, mean that is less than desireable.
>
>Yes, the side effect is the need for different std functions 
>to cope with different scenarios, but at least that makes the 
>programmer aware that there is a very real difference.

When you declare data structures you have to tell the compiler if they
are located in program memory or in data memory.  You then have a handy
pointer that can work with either type of data.  Obviously it is a
pointer to a const data type, so the data cannot be modified via that
pointer even if it is in data memory.  The whole idea is that a function
using this pointer dosen't have to be explicitly told where the data is,
it just works.  Wheres the problem exactly?

Regards

Mike

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