diff --git a/04_semantics_and_running/main.py b/04_semantics_and_running/main.py
index 6689b51..a3552e6 100644
--- a/04_semantics_and_running/main.py
+++ b/04_semantics_and_running/main.py
@@ -780,11 +780,9 @@ def compile_ast(node: ASTnode, compile_data: CompileData) -> None:
             elif node.value == '<':
                 compile_data.code.append(Instruction('cmpq', [register, '%rax']))
                 compile_data.code.append(Instruction('setl', ['%al']))
-                compile_data.code.append(Instruction('movzbq', ['%al', '%rax']))
             elif node.value == '=':
                 compile_data.code.append(Instruction('cmpq', [register, '%rax']))
                 compile_data.code.append(Instruction('sete', ['%al']))
-                compile_data.code.append(Instruction('movzbq', ['%al', '%rax']))
             else: assert False
 
             # If both operands are dates, divide result by number of seconds in a day
@@ -841,7 +839,7 @@ def compile_ast(node: ASTnode, compile_data: CompileData) -> None:
 
             # compile condition
             compile_ast(node.child_condition, compile_data)
-            compile_data.code.append(Instruction('testq', ['%rax', '%rax']))
+            compile_data.code.append(Instruction('testb', ['%al', '%al']))
             compile_data.code.append(Instruction('jz', [label_loop]))
         case 'do_unless' | 'unless_expression':
             label_true = compile_data.get_label()
@@ -849,7 +847,7 @@ def compile_ast(node: ASTnode, compile_data: CompileData) -> None:
 
             # compile condition
             compile_ast(node.child_condition, compile_data)
-            compile_data.code.append(Instruction('testq', ['%rax', '%rax']))
+            compile_data.code.append(Instruction('testb', ['%al', '%al']))
             compile_data.code.append(Instruction('jnz', [label_true]))
 
             # compile false statements