[patch] doc_stage1.S : GRUB on DoC

[Mark Meade]

Ilguiz Latypov wrote:

> Could that be due to change in MTD patch I made?  I added the
> informational message output "DoC found" at the time of ROM BIOS extension
> scan.  I wonder if the video card's BIOS extension can render INT 10h
> unstable at that time.

I don't think so -- I temporarily removed that message, and made sure that 
the initial code (what used to be in doc_stage1.S) matched the previous 
version that worked.  It didn't make any difference - it still locked up on 
the P-133's, but not on the Athlon.

For what it's worth, on one of the PC's, the lockup occurs at line 363, in 
the readbyte loop.  We copy a few pages OK (%di = 0x400, 0x500, 0x600), but 
lock up when %di is between 0x700 and 0x800, specifically with ES:DI equal to 
0x07E0:0x0719.

The other board makes it to the "Jumping to Grub" message, but then 
immediately reboots.

Mark