I use function pointer to bypass direct addressing. Fred -------------------------------------------- Frederic Beaulieu, M.Sc. Research and Development NewTrax Technologies Inc. http://www.newtraxtech.com/
-----Original Message----- From: mspgcc-users-ad...@lists.sourceforge.net [mailto:mspgcc-users-ad...@lists.sourceforge.net] On Behalf Of Dale Cunningham Sent: Friday, June 17, 2005 5:05 PM To: mspgcc-users@lists.sourceforge.net Subject: Re: [Mspgcc-users] bootstrap code N. Coesel wrote: > At 04:53 17-06-05 -0400, you wrote: > >>I'm trying to write a bootstrap routine in C that will reside in flash >>and be copied to RAM for execution. Can anyone give me some helpful >>hints on how to do that? > > > In an earlier discussion the method of copying a routine was discussed. That should be the easy part. I wasn't worried about that, but I'll check the archives just in case I'm missing something. >>I've searched the docs for any reference to relocatable code (there will >>be some subroutines, also in RAM) or preprocessor commands that might be >>able to specify that this code will be running at a particular address >>(in this case within the RAM) and haven't been able to find anything >>that relates to this problem. > > > Why would you copy more than one subroutine in RAM? The only thing you will > want in RAM is the code that actually programs the flash. The amount of > memory doesn't allow for allocating large fixed buffers for this. This BSL also needs to decrypt the data to be written to flash and handle some handshaking with the PC. The decryption routine might be erased at some point during the flash programming even if I only erase the segment about to be written. That wouldn't be good. And, part of the decryption algorhythm makes multiple calls to a subroutine, so that inlining that code would increase the size - this might not be a problem. I'm using an msp430x449 with 2k of RAM, so I think I'll have plenty of space for code and a communications buffer. So far, looking at the assembler output, it seems that calls are my only problem - they use direct addressing. So, I can just "fix" these few lines in the assembler or try indirect calls in C or just inline everything. Dale Cunningham ------------------------------------------------------- SF.Net email is sponsored by: Discover Easy Linux Migration Strategies from IBM. Find simple to follow Roadmaps, straightforward articles, informative Webcasts and more! Get everything you need to get up to speed, fast. http://ads.osdn.com/?ad_id=7477&alloc_id=16492&op=click _______________________________________________ Mspgcc-users mailing list Mspgcc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/mspgcc-users -- No virus found in this incoming message. Checked by AVG Anti-Virus. Version: 7.0.323 / Virus Database: 267.7.7/20 - Release Date: 6/16/2005 -- No virus found in this outgoing message. Checked by AVG Anti-Virus. Version: 7.0.323 / Virus Database: 267.7.7/20 - Release Date: 6/16/2005
