When the Destination and Source of an op_foo were types of different
sizes, the generated assembly was not filling up the "source" register
fully in some cases. This led to incorrect results.
This patch adds a basic ELF program loader to the UserspaceEmulator and
creates MMU regions for each PT_LOAD header. (Note that we don't yet
respect the R/W/X flags etc.)
We also turn the SoftCPU into an X86::InstructionStream and give it an
EIP register so we can actually execute code by fetching memory through
our MMU abstraction.
Let's use C++ templates to implement the generic parts of instructions.
There are tons of them with the same set of inputs, just different
behavior. Templates are perfect for this.
This patch adds a PartAddressableRegister type, which divides a 32-bit
value into separate parts needed for the EAX/AX/AL/AH register splits.
Clean up the code around register access to make it a little less
cumbersome to use.
This introduces a new X86 CPU emulator for running SerenityOS userspace
programs in a virtualized interpreter environment.
The main goal is to be able to instrument memory accesses and catch
interesting bugs that are very hard to find otherwise. But before we
can do fancy things like that, we have to build a competent emulator
able to actually run programs.
This initial version is able to run a very small program that makes
some tiny syscalls, but nothing more.
