sctrclr

When `mstateen0.CTR`=1, the SCTRCLR instruction performs the following operations: * Zeroes all CTR Entry Registers, for all DEPTH values * Reset to Zero the optional CTR cycle counter where implemented ** `ctrdata.CC` and `ctrdata.CCV` bit fields. Any read of `ctrsource`, `ctrtarget`, or `ctrdata` that follows SCTRCLR, such that it precedes the next qualified control transfer, will return the value 0. Further, the first recorded transfer following SCTRCLR will have `ctrdata.CCV`=0. SCTRCLR execution causes an `IllegalInstruction` exception if: * `Smctr` is not implemented * The instruction is executed in S/VS/VU-mode and `Ssctr` is not implemented, or `mstateen0.CTR`=0 * The instruction is executed in U-mode SCTRCLR execution causes a `VirtualInstruciton` exception if `mstateen0.CTR`=1 and: * The instruction is executed in VS-mode and `hstateen0.CTR`=0 * The instruction is executed in VU-mode

sctrclr