Bochs instruction emulation handlers won't refer to direct fields of instructions like MODRM.NNN or MODRM.RM anymore.
Use generic source/destination indications like SRC1, SRC2 and DST.
All handlers are modified to support new notation. In addition fetchDecode module was modified to assign sources to instructions properly.
Immediate benefits:
- Removal of several duplicated handlers (FMA3 duplicated with FMA4 is a trivial example)
- Simpler to understand fetch-decode code
Future benefits:
- Integration of disassembler into Bochs CPU module, ability to disasm bx_instruction_c instance (planned)
Huge patch. Almost all source files wre modified.
for CPU emulation performance reasons, the alignment check compilation
still can be enabled using configure option --enable-alignment-check.
There is no software in the world which enable #AC exception checking, this
x86 feature is completely legacy but its emulation support costs up to 3-5%
emulation speed.
The checking for #AC exception enable still will be done, if
CPL == 3, EFLAGS.AC = 1 and CR0.AM = 1
but the alignment check is not compiled in, the Bochs will PANIC with corresponding message.
You can press 'always continue' and ignore the PANIC, the simulation will continue as if alignment checking is not enabled.
The problem with Parity is it is generally referenced very rarely so the current lazy flags code is not efficient to updated Parify flag only (because it updates low 8 bits of .result value the existing Zero Flag has to be shadowed in .auxbits.
So I flipped it around, to make Parity be shadowed in auxbits. .result now is only needed to derive Zero Flag, and both Sign and Parify are derived from .result + .auxbits (as Zero Flag is now). For the 90% of the conditional jumps that are JZ or JNZ, this is a speedup.
Parity is now derived from 8 bits in .result and 8 bits in .auxbits, and Sign is derived from one flag in .result and 1 bit in .auxbits by XOR-ing them all together. It makes the code sequences for SAHF and POPF simpler too.
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Implemented SVN nested paging support - the Virtual Box boots perfectly with Nested Paging guest !
A lot of code duplication was added for now - major cleanup will follow later.
! Added AMD Phenom X3 8650 (Toliman) configuration to the CPUDB - this configuration has Nested Paging enabled.
Some CPUID modules rework done to enable Toliman configuration.
Ckean up 'executable' attribute from all CPU source files.
- IO intercept is not implemented yet
- MSR intercept is not implemented yet
VMX:
Fixed Bochs PANIC crash when doing I/O access crossing VMX I/O permission bitmaps.
This can happen because access_physical_read and access_physical_write cannot access memory cross 4K boundary.
I am merging the code in order to start making shortcuts between VMX emulation and SVM emulation.
Of course SVM emulation is incomplete, completely untested and not expected to work.
But someone could already take a look one the code and give some suggestions.
Also looking for anybody with existing SVM kernels - as simple as possible - for testing.
Status:
- exceptions intercept is not implemented yet
- IO intercept is not implemented yet
- MSR intercept is not implemented yet
- virtual interrupts are not implemented yet
- CPUID is not implemented yet
No advanced SVM featurez planned - I am implementing the very basic 'Pacifica' document from 2005 using QEMU code as reference.
