===============
Rairii changes:
memctrlbase: The memory controller may have an endian swap mode.
mpc106: Only mmio regions need endian swap and only if PCIR_LE_MODE is
set.
videoctrl: Add framebuffer_in_main_memory flag. Use needs_swap_endian.
debugger: Fix disasm for little endian mode.
ppcmmu: little endian mode requires munging of the data and instruction
addresses, affecting the 3 least significant bits.
ppcexec: pc_real is always recalculated during little endian mode
because instructions are swapped every 8 bytes (due to the address
munging).
==============
joevt changes:
Add SUPPORTS_MEMORY_CTRL_ENDIAN_MODE for memory controller.
Use cmake -DDPPC_SUPPORT_PPC_LE=ON to enable.
Add SUPPORTS_PPC_LITTLE_ENDIAN_MODE for CPU.
Use cmake -DDPPC_SUPPORT_MEM_LE=ON to enable.
Add ppc_change_endian to handle endian switch for MPC601 (uses HID0
instead of MSR) and later PPC CPUs.
Add is_LE flag to ppc_state to indicate little endian mode for all
processor versions.
Create separate ppc_exec_inner template functions for little and big
endian.
Switch endian mode in the ppc_exec outer functions when power_off_reason
is po_endian_switch.
Since MPC601 doesn't have ILE and LE bits, remove that code for that
CPU.
videoctrl: Uses templated methods. See next commit for a fix that this
change introduces.
In #135 we switched from a static OpcodeGrabber table to a
curOpcodeGrabber pointer in ppc_main_opcode. This results in an extra
indirection (as far as generated assembly having an additional load),
which reduces execution speed.
Switch to making the opcode grabber into a parameter to
ppc_main_opcode, and make ppc_exec_inner keep it up to date (via an
EXEF_OPCODE exception flag).
Also fixes FPU instructions in ppctests - we now need to set the FP
MSR bit when initializing the CPU.
Rather than running them normally, they should trigger a "no FPU"
exception. This appears to be required to allow correct graphical
rendering under Mac OS X - the FP bit cleared via mtmsr and rfi
instructions and something else appears to be relying on the exception
to be thrown.
Implemented by maintaining a parallel version of the OpcodeGrabber
table (OpcodeGrabberNoFPU) which contains alternate implementations
for all the floating point instructions. We switch the table whenever
the MSR value changes. This should minimize the overhead of doing
these checks.
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).