On Mon, Mar 18, 2019 at 11:22:55AM +0100, David Brown wrote: > I expect he could see it from looking at a disassembly. > > On The PPC cores, mftb and mftbu are simplified mnemonics, not > instructions - they are implemented as "mfspr" instructions on the > appropriate SPR registers (268 and 269). There also is an mftb instruction, primary opcode 31, secondary opcode 371 (mfspr is 31/339). There is an extended mnemonic "mftb rX" which means "mftb rX,268" in the old world, but "mfspr rX,268" when targeting newer ISAs. Segher
