Public bug reported:
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;
** Affects: qemu
Importance: Undecided
Status: New
** Affects: kvm (Ubuntu)
Importance: Undecided
Status: New
** Also affects: kvm (Ubuntu)
Importance: Undecided
Status: New
--
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https://bugs.launchpad.net/bugs/1239008
Title:
qemu fails to scroll screen on ^Vidmem output
Status in QEMU:
New
Status in “kvm” package in Ubuntu:
New
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;
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