On Dec 12, 2006, at 12:42 AM, Scott Dattalo wrote: >> I have some vague ideas about some pieces, such as the asmop set of >> functions which generate assembly code for operands, but I'm not even >> sure how that relates to the register allocation, or how the whole >> contraption determines what symbols are spillable, rematerializable, >> and so on. > > I didn't see a question in your message, but I think you're asking > how to > add 12-bit support to SDCC. Someone privately just asked what it would > take to do this and I said 6 man months. Fortunately, the 12-bit > port has > the luxury of building off of the 14-bit port. Who knows, maybe the > pCode > generation can accommodate both!
Hi Scott, Well, again, my question is, where do I start? When I look at the 14- bit port, I see (sorry for this...) a huge legacy application with little to no documentation. The pCode stuff just makes it worse because it's more stuff added on to the "standard" way to write backends that *must* be understood in order to morph the 14-bit code into a 12-bit port. Should I: a) Write the 12-bit port from scratch? b) Copy the 12-bit port from some non-PIC architecture and modify? c) Copy the 12-bit port from the 14-bit port and modify? And in each of these cases, where do I start? What decisions do I need to make? Do I need to understand the register allocation / spill / rematerialize algorithm fully before even attempting to touch ralloc.c, or is it sufficient to just change small portions of it? Can I make incremental changes to verify that things are working at each stage, or do I have to write the entire thing before testing? GCC has a porting guide... not that I could ever get it to work. It seemed to me that GCC required the entire (or a vast majority of the) port to be written in order to even function, so my experience with GCC was to write hundreds of lines of code that may or may not work, find a bug, grovel through the source code of GCC for a week to figure out what went wrong, ask in the forums (and get no answers)... it was a complete mess. :( --Rob ------------------------------------------------------------------------- Take Surveys. Earn Cash. Influence the Future of IT Join SourceForge.net's Techsay panel and you'll get the chance to share your opinions on IT & business topics through brief surveys - and earn cash http://www.techsay.com/default.php?page=join.php&p=sourceforge&CID=DEVDEV _______________________________________________ Sdcc-user mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/sdcc-user
