diff --git a/src/ieu/bmu/ext.sv b/src/ieu/bmu/ext.sv
index 346b7811d..0b4103273 100644
--- a/src/ieu/bmu/ext.sv
+++ b/src/ieu/bmu/ext.sv
@@ -41,7 +41,7 @@ module ext #(parameter WIDTH = 32) (
   assign zexthResult = {{(WIDTH-16){1'b0}},A[15:0]};
   assign sextbResult = {{(WIDTH-8){A[7]}},A[7:0]};
 
-  mux3 #(WIDTH) extmux(zexthResult, sextbResult, sexthResult, ExtSelect, ExtResult);
+  mux3 #(WIDTH) extmux(sextbResult, sexthResult, zexthResult, ExtSelect, ExtResult);
 
  
 endmodule
\ No newline at end of file
diff --git a/src/ieu/bmu/zbb.sv b/src/ieu/bmu/zbb.sv
index 654146291..f4b7eead8 100644
--- a/src/ieu/bmu/zbb.sv
+++ b/src/ieu/bmu/zbb.sv
@@ -55,7 +55,7 @@ module zbb #(parameter WIDTH=32) (
 
   cnt #(WIDTH) cnt(.A(A), .RevA(RevA), .B(B[4:0]), .W64(W64), .CntResult(CntResult));
   byteUnit #(WIDTH) bu(.A(A), .ByteSelect(B[0]), .ByteResult(ByteResult));
-  ext #(WIDTH) ext(.A(A), .ExtSelect({B[2], B[0]}), .ExtResult(ExtResult));
+  ext #(WIDTH) ext(.A(A), .ExtSelect({~B[2], {B[2] & B[0]}}), .ExtResult(ExtResult));
 
 
   assign MaxResult = (lt) ? B : A;