On Wed, May 09, 2012 at 08:57:53AM -0700, Alain Ribière wrote:
> Tanks for your answer.
>
>
> I have to apologize, I made a mistake. I rechecked my application and used
> git bisect.
> So I found that this is not a SeaBIOS issue (actually it's more a C-DOS
> issues...). My problem comes from this Qemu commit :
>
> 49669fc551e0ccd2310a9584a9b7343a0bcae477 is the first bad commit
> commit 49669fc551e0ccd2310a9584a9b7343a0bcae477
[...]
>
> Also I found the theorical memory map of the C-DOS in the documentation of my
> legacy application :
> start end
>
> 000000 9FFFF Program area
>
> 0A0000 0BFFFF Video memory
>
> 0C00000 0C7FFF BIOS graphic card
> 0C8000 0CBFFF BIOS cache controller
> 0CC000 0CFFFF BIOS removable disk
> 0D0000 0D3FFF BIOS network adapter
> 0D4000 0EFFFF CDOS system
> 0F0000 0FFFFF ROM BIOS
>
> I wonder what is the CDOS system at 0D4000... It seems a bit strange.
Very odd. This is still controlled by seabios. Indeed, if I apply
this (clearly incorrect) patch to seabios:
diff --git a/src/shadow.c b/src/shadow.c
index c0c8cc2..73c0670 100644
--- a/src/shadow.c
+++ b/src/shadow.c
@@ -83,7 +83,7 @@ make_bios_readonly_intel(u16 bdf, u32 pam0)
for (i=0; i<6; i++) {
u32 mem = BUILD_ROM_START + i * 32*1024;
u32 pam = pam0 + 1 + i;
- if (RomEnd <= mem + 16*1024) {
+ if (0 && RomEnd <= mem + 16*1024) {
if (RomEnd > mem)
pci_config_writeb(bdf, pam, 0x31);
break;
Then the C-DOS image you posted seems happier. Basically, if C-DOS is
allowed to write to the e-segment then it seems to do weird things.
>
> I do not understand why this commit affects the C-DOS memory allocation.
> But you're probably right, C-DOS is using memory addresses he shouldn't for
> it's own purpose causing conflicts...
>
> If you have any idea.
>
>
> Thanks, and sorry again for the wrong issue (I will remove the SeaBIOS
> mailing list in the future mails)...
>
This is still in the SeaBIOS realm. (Though I'm thinking it's really
a C-DOS bug.)
-Kevin
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