Some of these accept a 4th register "C" so they exist in the opcode table 32 times.
Some of these don't accept a 4th register "C" so they exist in the opcode table once.
Instead of a primary opcode lookup table with 64 entries and a few
smaller tables with 4-2048 entries, use a single 64 * 2048 (128K)
entry table to dispatch opcodes.
Helps with performance, since we avoid the function call overhead for
some frequently-used instructions (e.g. branch, integer, floating point).
Saves ~2 seconds from the time to Welcome to Macintosh (same measurement
methodology as #125)
Secondarily also makes opcode registration/decoding a bit more uniform,
and scannable, since it's now all in initialize_ppc_opcode_table.
Replace it wth an explicit opcode parameter that is passed around. That
is both slightly easier to reason about (to trace where it comes from)
and slightly faster, since it can be read from a register.
On my machine takes booting to "Welcome to Macintosh" being output in
a verbose boot of Mac OS X 10.2.8 from 31.8s to 30.6s (average of 5
runs, measured using deterministic mode and looking at when execution
reaches PC 0x90004a88).
ppc_opcode16 and other functions are only needed in the implementation in
ppcexec.cpp, they don't need to be in the header.
fp_return_double and fp_return_uint64 have no uses (as of 2141a72b873763995b3428353dc7fd9d5bb47abb)
can can thus be removed altogether.
Similarly ppc_fpu_off has no uses (as of bb3f4e596e3f18f9414daa94e3639d2c192e93ec)
and can be removed.
Before f65f9b9845ddf0a4050213cc36ef43c9c852a6c7 this would happen
automatically (since the stream member was always valid). It's now a
unique_ptr that's only initialized when the file is opened, so we need
to add guards for all the operations.
We only need up to BE_FB_OFFSET + this->vram_size.
If vram_size is 8MB, then make sure the last 4K is not mapped to BAR 0 because the macOS driver likes to map BAR 2 at that location.
The previous approach of traversing the machine and its device tree
at startup to register CLI11 options was not working for dynamically
registered devices like PCI cards. This meant that options like
gfxmem_size or mon_id from the video cards could not be set.
Switch to instead registering in MachineFactory a hook function that
provides CLI flag values. We can call it when registering any property,
whether at startup or dynamically.
Have the entire dbdma program executed by scheduling each iteration in the CPU loop.
This is done only for devices that use the dbdma program to drive data input/output (has_data_callbacks) rather than have the device drive the dbdma program.
