diff --git a/software/include/fpvm/ast.h b/software/include/fpvm/ast.h
index a1a79d22..6fb54fb5 100644
--- a/software/include/fpvm/ast.h
+++ b/software/include/fpvm/ast.h
@@ -47,7 +47,7 @@ enum ast_op {
 	op_min,
 	op_max,
 	op_int,
-	op_vops,	/* virtual operations start here */
+	op_not,
 };
 
 /* maximum supported arity is 3 */
diff --git a/software/libfpvm/fpvm.c b/software/libfpvm/fpvm.c
index 8bac60ad..dd8b9aed 100644
--- a/software/libfpvm/fpvm.c
+++ b/software/libfpvm/fpvm.c
@@ -522,6 +522,12 @@ static int compile(struct fpvm_fragment *fragment, int reg, struct ast_node *nod
 			return FPVM_INVALID_REG;
 		ADD_ISN(FPVM_OPCODE_TSIGN, opa, opb, reg);
 		break;
+	case op_not:
+		opb = REG_CONST(0);
+		if(opb == FPVM_INVALID_REG)
+			return FPVM_INVALID_REG;
+		ADD_ISN(FPVM_OPCODE_EQUAL, opa, opb, reg);
+		break;
 	default:
 		/* Normal case */
 		opcode = operator2opcode(node->op);