data(inst): add long_name and description for sctclr

Co-authored-by: David Brash <[email protected]>

Author: dhower-qc

arch/inst/Smdbltrp/sctrclr.yaml

@@ -3,9 +3,27 @@
 $schema: inst_schema.json#
 kind: instruction
 name: sctrclr
-long_name: No synopsis available.
+long_name: Supervisor Control Transfer Record (CTR) clear
 description: |
-  No description available.
+  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.CC` 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
 definedBy:
   anyOf: [Smctr, Ssctr]
 assembly: sctrclr