improve handling of various illegal instruction conditions
Created by: strichmo
The ISACOV model now will "pass through" illegal instructions for downstream analysis export subscribers to use. Add multiple illegal conditions to the illegal directed test to verify coverage scenarios. Ensure that the ISACOV handles the following illegal instruction conditions:
- reserved opcode
- Reserved operand in valid opcode
- Illegal/unsupported CSR in valid CSR instruction
- Valid opcode with unsupported extension
Signed-off-by: Steve Richmond Steve.Richmond@silabs.com