diff --git a/sw/tools/fp_lexer.mll b/sw/tools/fp_lexer.mll
index 5e9a397cc8..69f8d787de 100644
--- a/sw/tools/fp_lexer.mll
+++ b/sw/tools/fp_lexer.mll
@@ -23,6 +23,7 @@ rule token = parse
   | "&&" { AND }
   | "||" { OR }
   | ">" { GT }
+  | "%" { MOD }
   | ">=" { GEQ }
   | "+" { PLUS }
   | "=" { ASSIGN }
diff --git a/sw/tools/fp_parser.mly b/sw/tools/fp_parser.mly
index 75555fc6e5..02933987aa 100644
--- a/sw/tools/fp_parser.mly
+++ b/sw/tools/fp_parser.mly
@@ -9,13 +9,12 @@ open Fp_syntax
 %token COMMA SEMICOLON LP RP LC RC LB RB AND COLON OR
 %token EQ GT ASSIGN GEQ NOT
 %token PLUS MINUS
-%token MULT DIV
-
+%token MULT DIV MOD
 
 %left AND OR	/* lowest precedence */
 %left EQ GT ASSIGN GEQ
 %left PLUS MINUS
-%left MULT DIV
+%left MULT DIV MOD
 %nonassoc NOT
 %nonassoc UMINUS	/* highest precedence */
 
@@ -34,6 +33,7 @@ expression:
   | expression MINUS expression { CallOperator ("-",[$1;$3]) }
   | expression MULT expression { CallOperator ("*",[$1;$3]) }
   | expression DIV expression { CallOperator ("/",[$1;$3]) }
+  | expression MOD expression { CallOperator ("%",[$1;$3]) }
   | MINUS expression %prec UMINUS { CallOperator ("-",[$2]) }
   | NOT expression { CallOperator ("!",[$2]) }
   | INT { Int $1 }