Reserve interrupt 13 for Sscofpmf

Resolves #1127

Note, I only reserved the pattern in the various cause registers; I did not
update the various ip/ie registers.  That work is left for whoever integrates
Sscofpmf into this document.  Reserving the cause patterns has the same
architectural effect in the near term.

src/hypervisor.adoc

@@ -1755,11 +1755,14 @@ Virtual supervisor external interrupt +
 Machine external interrupt 
 |1 +
 1 +
+1 +
 1
 |12 +
-13-15 +
+13 +
+14-15 +
 ≥16
 |Supervisor guest external interrupt +
+_Reserved for counter-overflow interrupt_ +
 _Reserved_ +
 _Designated for platform use_
 |0 +

src/machine.adoc

@@ -1677,10 +1677,16 @@ Supervisor external interrupt +
 _Reserved_ +
 Machine external interrupt 
 |1 +
+1 +
+1 +
 1
-|12-15 +
+|12 +
+13 +
+14-15 +
 ≥16
 |_Reserved_ +
+_Reserved for counter-overflow interrupt_ +
+_Reserved_ +
 _Designated for platform use_ 
 |0 +
 0 +

src/priv-preface.adoc

@@ -37,6 +37,7 @@ version 1.12:
 * Defined the `misa`.V field to reflect that the V extension has been
 implemented.
 * Defined the RV32-only `medelegh` and `hedelegh` CSRs.
+* Reserved interrupt 13 for forthcoming counter-overflow interrupt extension.
 * Specified synchronization requirements when changing the PBMTE fields
 in `menvcfg` and `henvcfg`.
 * Clarified that "platform- or custom-use" interrupts are actually

src/supervisor.adoc

@@ -425,14 +425,18 @@ include::images/bytefield/scausereg.edn[]
 1 +
 1 +
 1 +
+1 +
+1 +
 1
 |0 +
 1 +
 2-4 +
 5 +
 6-8 +
 9 +
-10-15 +
+10-12 +
+13 +
+14-15 +
 ≥16
 |_Reserved_ +
 Supervisor software interrupt +
@@ -441,6 +445,8 @@ Supervisor timer interrupt +
 _Reserved_ +
 Supervisor external interrupt +
 _Reserved_ +
+_Reserved for counter-overflow interrupt_ +
+_Reserved_ +
 _Designated for platform use_ 
 
 |0 +