diff --git a/t1/src/decoder/Decoder.scala b/t1/src/decoder/Decoder.scala
index e569953e9..36099d767 100644
--- a/t1/src/decoder/Decoder.scala
+++ b/t1/src/decoder/Decoder.scala
@@ -215,14 +215,14 @@ object Decoder {
 
   object topUop extends T1UopField {
     override def genTable(pattern: T1DecodePattern): BitPat = pattern.topUop.value match {
-      case _: TopT0.type => BitPat("b000")
-      case _: TopT1.type => BitPat("b001")
-      case _: TopT2.type => BitPat("b010")
-      case _: TopT3.type => BitPat("b011")
-      case _: TopT5.type => BitPat("b101")
-      case _: TopT6.type => BitPat("b110")
-      case _: TopT7.type => BitPat("b111")
-      case _ => BitPat.dontCare(3)
+      case _: TopT0.type => BitPat("b0000")
+      case _: TopT1.type => BitPat("b0001")
+      case _: TopT2.type => BitPat("b0010")
+      case _: TopT3.type => BitPat("b0011")
+      case _: TopT5.type => BitPat("b0101")
+      case _: TopT6.type => BitPat("b0110")
+      case _: TopT7.type => BitPat("b0111")
+      case _ => BitPat.dontCare(4)
     }
   }