[ECOS] i386 Memory Size Problem

kevin_lemay@agilent.com kevin_lemay@agilent.com
Mon Nov 24 22:53:00 GMT 2003

There appears to be an issue with the pcmb_misc.c file where it determines to actual amount of extended memory available.

It is reading bytes 0x17 and 0x18 from the CMOS which limits the RAM size to 64MB.

I was trying to find the proper way to find out the memory size, and found the following on the web.

Use BIOS calls: 
INT 15h AX=E820h (32-bit CPU only). If this fails... 
...use INT 15h AX=E801h. If this fails... 
...use INT 15h AH=88h. 
Read the extended memory size from CMOS only if all of the BIOS calls listed above fail. 

How do I do this with eCos?

I have a large application that I am porting that allocates lots of ram. I need more than 64MB.


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