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commit 408e06e258422bc402077bff77659bc13a2a2f81
parent 1af2b66ae1b64f177c6e56bf0f59942025d1e7be
Author: Bradley Gannon <bradley@bradleygannon.com>
Date:   Thu,  1 Oct 2026 23:26:24 -0400

Fix a bug where certain jalr instructions did bad arithmetic

Diffstat:
M
src/main/scala/controlUnit.scala
 | 
4
+++-

1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/src/main/scala/controlUnit.scala b/src/main/scala/controlUnit.scala
@@ -243,7 +243,9 @@ class AluDecoder extends Module {
     }
     is(AluOp.arithmetic) {
       when(
-        io.funct3 === "b000".U && (!io.op.asUInt(5) || (io.op.asUInt(5) && !io.funct7_5))
+        io.funct3 === "b000".U && (io.op === Opcode.jalr || !io.op.asUInt(5) || (io.op.asUInt(
+          5
+        ) && !io.funct7_5))
       ) {
         io.aluControl := AluControl.add
       }.elsewhen(io.funct3 === "b000".U && io.op.asUInt(5) && io.funct7_5) {