qemu fails to scroll screen on ^Vidmem output

Bug #1239008 reported by rjasmin
6
This bug affects 1 person
Affects Status Importance Assigned to Milestone
QEMU
Expired
Undecided
Unassigned
qemu (Ubuntu)
Expired
Low
Unassigned

Bug Description

Pascal uses ^Vidmem for B800 console output. The terminal does not oblige the Pascal OS code to scroll the output. Virtualbox emulation works, so this must be a qemu bug. Using QEMU in KVM mode as Ubuntu LTS.

Source line to trip bug(in theory pushes VideoMem up one line):

procedure Scroll;
//this is whats causing crashes. FIXME:Virtualbox not affected.QEMU BUG?
begin
  if scrolldisabled then exit;
      if (CursorPosY >= 24) then begin //in case called before end of screen
    blank:= $20 or (TextAttr shl 8);
    Move((VidMem+(2*80))^,VidMem^,24*(2*80));
    // Empty last line
    FillWord((VidMem+(24*2*80))^,80,Blank);
    CursorPosX:=1;
    CursorPosY:=23;
    update_cursor;
  end;
end;

Revision history for this message
Serge Hallyn (serge-hallyn) wrote :

Thanks for reporting this bug. Is there any other reproducer you can give us?

no longer affects: kvm (Ubuntu)
Changed in qemu (Ubuntu):
status: New → Incomplete
Changed in qemu:
status: New → Incomplete
Revision history for this message
rjasmin (frazzledjazz) wrote : Re: [Bug 1239008] Re: qemu fails to scroll screen on ^Vidmem output

I dont know how to write it myself, but the original kernel scrolling
code is in C.
Might try OSDev forums. Not that I know of.

On 11/27/2013 09:24 PM, Serge Hallyn wrote:
> Thanks for reporting this bug. Is there any other reproducer you can
> give us?
>
> ** No longer affects: kvm (Ubuntu)
>
> ** Also affects: qemu (Ubuntu)
> Importance: Undecided
> Status: New
>
> ** Changed in: qemu (Ubuntu)
> Status: New => Incomplete
>
> ** Changed in: qemu
> Status: New => Incomplete
>

Changed in qemu (Ubuntu):
status: Incomplete → New
Changed in qemu:
status: Incomplete → New
Changed in qemu (Ubuntu):
importance: Undecided → Low
Revision history for this message
Chris J Arges (arges) wrote :

Can you test with the latest version to see if this still affects you?
If this still is a problem, any information on how to obtain the Guest OS in question that would also be helpful.

Changed in qemu (Ubuntu):
status: New → Incomplete
Revision history for this message
rjasmin (frazzledjazz) wrote :

It is hosted on google code, a dying service. FreePascal(coffee) OS.A
more basic version is posted there.I assume it works as the version that
I last built did not for some reason. Sources should be there via
subversion checkout.Thats what I tested with.
https://code.google.com/p/coffee-os/

  It uses a basic VRAM scroll buffer and writes to it.

Examples are found elsewhere in C. (OS Dev pages)
Im in the middle of a fedup upgrade at the moment, but will see what I
can do.

On 06/17/2015 12:11 PM, Chris J Arges wrote:
> Can you test with the latest version to see if this still affects you?
> If this still is a problem, any information on how to obtain the Guest OS in question that would also be helpful.
>
> ** Changed in: qemu (Ubuntu)
> Status: New => Incomplete
>

Revision history for this message
Thomas Huth (th-huth) wrote :

Triaging old bug tickets... can you still reproduce this issue with the latest version of QEMU? Or could we close this ticket nowadays?

Changed in qemu:
status: New → Incomplete
Revision history for this message
Launchpad Janitor (janitor) wrote :

[Expired for QEMU because there has been no activity for 60 days.]

Changed in qemu:
status: Incomplete → Expired
Revision history for this message
Launchpad Janitor (janitor) wrote :

[Expired for qemu (Ubuntu) because there has been no activity for 60 days.]

Changed in qemu (Ubuntu):
status: Incomplete → Expired
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