First off: sorry for CCing, I was not subscribed to llvm-dev in March so couldn't reply directly... I've been following the discussion and was wondering if either of is aware of Ghidra's slaspec: it specifies instruction encoding along with instruction semantics through what they call pcode. For instructions that go beyond what a simple RTL can express, like flushing caches or alike, you can define custom pcode functions whose actual implementation you can fill in yourself. See [1] for an example. This means that for code that don't require custom pcode functions, you bascially get emulation for free. See [2] for the C++ code needed to do emulation. In the C++ code, you can also provide the implementation of custom pcode functions. Dabbling with the PPC backend's TableGen files myself from time to time, I find myself wishing there was something to sleigh's p-code and your discussion immediately rang a dozen bells ;) Redards, Thomas [1] https://github.com/NationalSecurityAgency/ghidra/blob/e7488245fd3e85dea6050e0dd66bb4a4dbeeb53b/Ghidra/Processors/PowerPC/data/languages/ppc_instructions.sinc [2] https://github.com/NationalSecurityAgency/ghidra/blob/e7488245fd3e85dea6050e0dd66bb4a4dbeeb53b/Ghidra/Features/Decompiler/src/decompile/cpp/sleighexample.cc#L250 -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.llvm.org/pipermail/llvm-dev/attachments/20210418/586abdb4/attachment.html>