[ECOS] The 640k barrier

David N. Welton davidw@dedasys.com
Mon Dec 29 21:01:00 GMT 2003

Leandro Fanzone <leandro@hasar.com> writes:

> We're planning a 2M i386 board, and though I declare through the
> mlt_i386_pc_floppy files such thing, malloc always stops when the
> pointer reaches the 640k barrier.

You might try recompiling... a few times, or running the 'ecosconfig
tree' command.  I always found that getting this to work was a little
bit fiddly.

If you want, you can download and look at the "Scivoli" code on my
free software page (link below).  That definitely uses more than the
base 640K.

> It's also a concern for us that the code can't be moved to the upper
> meg, because the linker complains "relocation truncated to fit",
> something related to vectors.o, so I assume that the interrupt
> vectors drag the code to the lower meg, and therefore can't be moved
> that high. Our code will be large enough to exceed the 640k, so the
> best for us would be to map the code in the upper meg, and let data
> and heap in the lower 640k. Can someone help me with this?

That is a question for the real experts:-)

Good luck,
David N. Welton
   Consulting: http://www.dedasys.com/
     Personal: http://www.dedasys.com/davidw/
Free Software: http://www.dedasys.com/freesoftware/
   Apache Tcl: http://tcl.apache.org/

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