mask node outputs according to their bit width

closes #44

Author: steveRoll-git

src/logic/blueprints/singleCycle.ts

@@ -201,7 +201,7 @@ export const singleCycle: Blueprint = {
     },
     splitterImmediateALUOp: {
       type: makeSplitter(2, [
-        [0, 31],
+        [0, 15],
         [0, 5],
       ]),
       outputs: {

src/logic/nodeTypes/splitter.ts

@@ -41,10 +41,16 @@ export function makeSplitter(
       return values
     },
     undefined,
-    bitRanges &&
-      (() =>
-        Object.fromEntries(
-          bitRanges.map((r, i) => [`out${i}`, r[1] - r[0] + 1]),
-        )),
+    (get) =>
+      Object.fromEntries(
+        // If `bitRanges` is given, the bit width of each output will be calculated according to the bit range.
+        // Otherwise, it'll be the same width as the input.
+        bitRanges
+          ? bitRanges.map((r, i) => [`out${i}`, r[1] - r[0] + 1])
+          : Array.from({ length: numOutputs }, (_, i) => [
+              `out${i}`,
+              get("in"),
+            ]),
+      ),
   )
 }

src/logic/simulation.ts

@@ -444,10 +444,18 @@ export function simulationStep(simulation: Simulation): Simulation {
         const outputs = node.type.executeRising(simulation, inputValues)
         for (const outputId in outputs) {
           // Forward each output value to its target input.
+          let value = outputs[outputId]
+
+          if (node.outputBitWidths) {
+            const bitWidth = node.outputBitWidths[outputId]
+            if (bitWidth != 32) {
+              value = value & ((1 << bitWidth) - 1)
+            }
+          }
+
           const [targetNodeId, targetInputId] = getNodeTarget(
             node.outputs[outputId],
           )
-          const value = outputs[outputId]
           newInputValues[targetNodeId] = {
             ...newInputValues[targetNodeId],
             [targetInputId]: value,