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From: s_dubrovich on 8 May 2010 09:48
On May 8, 5:57 am, Mike Gonta <mikego...(a)gmail.com> wrote:
> On May 7, 10:03 pm, s_dubrov...(a)yahoo.com wrote:
>
> > Sure.. from power-on cold boot & ctrl-alt-del reboot, both give:
> > A:\>stack
> > 00000030:00000100
>
> > -I guess that says something :)
>
> Thanks Steve, it sure does.
> I've corrected the bug in rm2pm.asm where I was using the pm
> stack pointer before converting from the rm version. It was no
> problem when ss was 0 because real mode 0:offset is the same
> as protected mode offset.
> I've removed the stack initialization in boot.asm, as I am convinced
> that the BIOS stack (even when located in the lower IVT) is sufficient
> for the initial setup code.

But this latest version doesn't complete its boot either, in my case.
I can't explain it either, but it occurs to me that 30:0100 for SS:SP
also doubles as a pm selector:offset value.

Steve

> As a side note, on one PC I tested when I used 0:7C00h for
> the stack pointer it froze when rm2pm returned to the boot sector.
> Other values such as 0:7B00h and 0:0FFFEh were OK and this
> PC showed a BIOS stack in the 0:400 region. The strange thing is
> that the "start" monitor uses 7C00h and that PC worked fine as
> long as I didn't use that as the initial value. Of course the latest
> release tested OK with this PC.
>
> Mike Gonta
> look and see - many look but few see
>
> http://mikegonta.com/pdBIOS32

From: Mike Gonta on 8 May 2010 11:44
On May 8, 9:48 am, s_dubrov...(a)yahoo.com wrote:

> But this latest version doesn't complete its boot either, in my case.

Hi Steve,

I don't think the change in rm2pm.asm made it into the first release
today.
Please try the latest version "pdBIO32 20100508.01.img"

> I can't explain it either, but it occurs to me that 30:0100 for SS:SP
> also doubles as a pm selector:offset value.

In protected mode the ss is always 16 which is the 3rd entry in the
GDT
in rm2pm. This is the 4 Gb flat address space for data. When entering
real mode the ss is always set to 0 and if esp is greater than 0FFFCh
it is saved to be restored later and changed to 7C00h.


Mike Gonta
look and see - many look but few see

http://mikegonta.com/pdBIOS32
From: s_dubrovich on 8 May 2010 12:40
On May 8, 10:44 am, Mike Gonta <mikego...(a)gmail.com> wrote:
> On May 8, 9:48 am, s_dubrov...(a)yahoo.com wrote:
>
> > But this latest version doesn't complete its boot either, in my case.
>
> Hi Steve,
>
> I don't think the change in rm2pm.asm made it into the first release
> today.
> Please try the latest version "pdBIO32 20100508.01.img"
>
Success!

Steve

> > I can't explain it either, but it occurs to me that 30:0100 for SS:SP
> > also doubles as a pm selector:offset value.
>
> In protected mode the ss is always 16 which is the 3rd entry in the
> GDT
> in rm2pm. This is the 4 Gb flat address space for data. When entering
> real mode the ss is always set to 0 and if esp is greater than 0FFFCh
> it is saved to be restored later and changed to 7C00h.
>
A detail that is good to know.

> Mike Gonta
> look and see - many look but few see
>
> http://mikegonta.com/pdBIOS32

From: Mike Gonta on 8 May 2010 14:32
On May 7, 9:56 pm, "Rod Pemberton" <do_not_h...(a)havenone.cmm> wrote:

> It reliably enters the monitor too.  That probably eliminates port_92_A20
> and wait_A20 as issues.  That was against ...506 image.

Hi Rod,

I've eliminated the redundant code for disabling and enabling the
keyboard
controller in port_60_A20 in rm2pm.asm. This "standard" simplified
procedure
may fix the problem.

> The port_92_A20 not being an issue surprise me a bit...

I've also successfully tested 2 PC's which can only enable the A20 by
the
keyboard controller by first trying the fast port 92 method without
problems.

The latest release is "pdBIOS32 20100508.02.img"


Mike Gonta
look and see - many look but few see

http://mikegonta.com/pdBIOS32


From: Rod Pemberton on 8 May 2010 16:41
"Mike Gonta" <mikegonta(a)gmail.com> wrote in message
news:cda929a2-3667-43ea-8278-a99ecfe37935(a)h11g2000vbo.googlegroups.com...
>
> The latest release is "pdBIOS32 20100508.02.img"
>

pdBIOS32 20100508.02.img

Pentium-MMX, 233Mhz, Award Modular BIOS v4.51 PG
00000000:000003FA

Made it to the prompt. App's and kernel commands work. Still works on
2.8Ghz. (Sorry, 450Mhz machine is now in use...)

Oh, I forgot to mention that I also tried a USB stick boot on the 2.8Ghz
machine with one of the earlier images (501 or 505). It worked.


Rod Pemberton


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