+    counter_info[20] = Type (0 = HARDWARE and 1 = SOFTWARE)
+    counter_info[XLEN-1:21] = Reserved for future use
+----
+
+If `counter_info.type == 0x1` then `counter_info.csr` should be ignored
+and `counter_info.width` is assumed to be XLEN.

Perhaps we should store the type in bit 31 to allow for easier
branching?

That wouldn’t help 64-bit targets much.  Did you mean bit XLEN-1?

Tommy