feat(river_hdl): adding microcode execution

Author: RossComputerGuy

packages/riscv/lib/src/ops.dart

@@ -1385,7 +1385,8 @@ class Microcode {
     fieldIndices,
   ).width;
 
-  int get opIndexWidth => decodeLookup.keys.fold(0, (a, b) => a > b ? a : b);
+  int get opIndexWidth =>
+      decodeLookup.keys.fold(0, (a, b) => a > b ? a : b).bitLength;
 
   int opWidth(Mxlen mxlen) => map.values
       .map((op) => op.microcodeWidth(mxlen))

packages/river_hdl/lib/src/core.dart

@@ -245,7 +245,7 @@ class RiverCoreIP extends BridgeModule {
       // TODO: drive pagingMode, pageTableAddress, mxr, and sum from CSRs
     }
 
-    final microcodeRead = DataPortInterface(
+    final microcodeDecodeRead = DataPortInterface(
       config.microcode.patternWidth,
       config.microcode.map.length.bitLength,
     );
@@ -255,7 +255,7 @@ class RiverCoreIP extends BridgeModule {
         clk,
         reset,
         [],
-        [microcodeRead],
+        [microcodeDecodeRead],
         numEntries: config.microcode.map.length,
         resetValue: config.microcode.encodedPatterns,
         definitionName: 'RiverMicrocodeLookup',
@@ -279,10 +279,13 @@ class RiverCoreIP extends BridgeModule {
       rs2Read,
       rdWrite,
       config.microcodeMode.onDecoder != MicrocodePipelineMode.none
-          ? microcodeRead
+          ? microcodeDecodeRead
           : null,
+      null,
       useMixedDecoders:
           config.microcodeMode.onDecoder == MicrocodePipelineMode.in_parallel,
+      useMixedExecution:
+          config.microcodeMode.onExec == MicrocodePipelineMode.in_parallel,
       microcode: config.microcode,
       mxlen: config.mxlen,
       hasSupervisor: config.hasSupervisor,

packages/river_hdl/lib/src/core/csr.dart

@@ -119,7 +119,7 @@ class RiscVCsrFile extends Module {
     addOutput('mideleg', width: mxlen.size);
     addOutput('medeleg', width: mxlen.size);
     addOutput('mtvec', width: mxlen.size);
-    addOutput('stvec', width: mxlen.size);
+    if (hasSupervisor) addOutput('stvec', width: mxlen.size);
 
     void _checkFits(String n, int v) {
       final max = (mxlen.size >= 63) ? null : (1 << mxlen.size);
@@ -197,6 +197,7 @@ class RiscVCsrFile extends Module {
         _csrTop.getBackdoorPortsByAddr(0, CsrAddress.medeleg.address).rdData!;
     mtvec <=
         _csrTop.getBackdoorPortsByAddr(0, CsrAddress.mtvec.address).rdData!;
+
     if (hasSupervisor)
       stvec! <=
           _csrTop.getBackdoorPortsByAddr(0, CsrAddress.stvec.address).rdData!;
@@ -568,17 +569,17 @@ class RiscVCsrFile extends Module {
     _fdRead.addr <= rdAddr12;
     _fdRead.en <= csrRead.en & rdLegal;
     csrRead.data <= _fdRead.data;
-    csrRead.done <= _fdRead.done | csrRead.en;
-    csrRead.valid <= _fdRead.valid & rdLegal;
+    csrRead.done <= _fdRead.done & csrRead.en;
+    csrRead.valid <= _fdRead.valid & csrRead.en & rdLegal;
 
     _fdWrite.addr <= wrAddr12;
 
     final maskedWriteData = _maskWriteData(wrAddr12, csrWrite.data);
     _fdWrite.data <= maskedWriteData;
 
     _fdWrite.en <= csrWrite.en;
-    csrWrite.done <= _fdWrite.done;
-    csrWrite.valid <= _fdWrite.valid & wrLegal;
+    csrWrite.done <= _fdWrite.done & csrWrite.en;
+    csrWrite.valid <= _fdWrite.valid & csrWrite.en & wrLegal;
   }
 
   void _bindBackdoorForCounters() {