[syslinux] Nasty Bug (BIOS?).

Arwin Vosselman testteam at xs4all.nl
Thu Aug 18 05:15:14 PDT 2005


At first I thought, I was dealing with the known EBIOS/CBIOS-problem.
The symptom was exactly the same (hangs at ...EBIOS). As 3.10-pre8 and
3.10-pre9, in contrary what was mentioned in the ML, did not bring any
improvement, I looked deeper into what could be my specific problem.

I found out that the program just halted at 'cmp [esi],edx' (line 658;
ldlinux.asm 3.10-pre9)! By replacing that code by 'cmp [si],edx' the
problems were gone, it worked like a charm;-) The only thing I can think
of to cause this is that the 16 high bits of esi are incorrect. (An
opcode-bug for this command seemed out of the question.)

After putting 'cmp [esi],edx' back and putting in a command 'xor esi,esi'
after line 641 it works again like a charm. This proves IMO my theory
that the high 16 bits of esi were set to some undesired value.

Probably the BIOS is setting the 16 high bits of esi to some value
causing 'cmp [esi], edx' to go beyond the maximum.

Hardware: MB Chaintech 5AGM2, BIOS Award v4.51PG, Intel Pentium 166-MMX,
HDD 6GB.

-- 
Regards,
Arwin.




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