1 files changed, 3 insertions, 0 deletions

diff --git a/parse-events.c b/parse-events.c
index eb0812f..aef46c8 100644
--- a/parse-events.c
+++ b/parse-events.c
@@ -2104,6 +2104,9 @@ static unsigned long long eval_num_arg(void *data, int size,
                                 die("unknown op '%s'", arg->op.op);
                         val = left == right;
                         break;
+                case '-':
+                        val = left - right;
+                        break;
                 default:
                         die("unknown op '%s'", arg->op.op);
                 }