This patch introduces the concept of shadow bits. For every byte of
memory there is a corresponding shadow byte that contains metadata
about that memory.
Initially, the only metadata is whether the byte has been initialized
or not. That's represented by the least significant shadow bit.
Shadow bits travel together with regular values throughout the entire
CPU and MMU emulation. There are two main helper classes to facilitate
this: ValueWithShadow and ValueAndShadowReference.
ValueWithShadow<T> is basically a struct { T value; T shadow; } whereas
ValueAndShadowReference<T> is struct { T& value; T& shadow; }.
The latter is used as a wrapper around general-purpose registers, since
they can't use the plain ValueWithShadow memory as we need to be able
to address individual 8-bit and 16-bit subregisters (EAX, AX, AL, AH.)
Whenever a computation is made using uninitialized inputs, the result
is tainted and becomes uninitialized as well. This allows us to track
this state as it propagates throughout memory and registers.
This patch doesn't yet keep track of tainted flags, that will be an
important upcoming improvement to this.
I'm sure I've messed up some things here and there, but it seems to
basically work, so we have a place to start! :^)
LibPThread: mark pthread_exit a noreturn function using compiler attributes
LibThread: remove a call to pthread_exit from Thread::start lambda expression
as it make the return of teh lambda unreachable.
This allows us to determine which mode to render the page in.
Exposes "doctype" and "compatMode" on Document.
Exposes "name", "publicId" and "systemId" on DocumentType.
ControlBoxButton consolidates the paint_event for buttons
used in composite box widgets like ComboBox and SpinBox. Its
button bitmaps are built with create_from_ascii like WindowFrame
and ScrollBar controls, making theming more uniform.
These were not recording the higher part of the result correctly.
Since the flags are much less complicated than the inline assembly
here, just implement IMUL in C++ instead.
I totally forgot about the C++ basics here. There are three distinct
types: "char", "signed char" and "unsigned char". Whether "char" is
signed or unsigned is implementation specific.
With this, System Monitor has "System Monitor" instead of
"SystemMonitor" as tooltip, matching the app's title bar
and menu bar title.
Same for File Manager and Text Editor.
If we add "(Not responding)" to the title of an unresponsive window,
the title rect needs to be wider or we'll have text-on-stripes.
Thanks to @SharpOB for reporting this bug!
The theming system can now control title bar height, title button
size, title stripe color and the title text shadow color.
The implemented theme metrics system could be later extended to LibGUI
to allow themes to change widget padding, border width, etc.
Add all 6 shortcuts even if the switch between VirtualConsoles is
currently not available in the graphical console.
Also make the case statement more compact.
It is possible to switch to VirtualConsoles 1 to 4 via the shortcut
ALT + [1-4]. Therefor the array of VirtualConsoles should be guaranteed
to be initialized.
Also add an constant for the maximum number of VirtualConsoles to
guarantee consistency.
