diff --git a/src/bf.c b/src/bf.c
index deeef3e..e938712 100644
--- a/src/bf.c
+++ b/src/bf.c
@@ -105,6 +105,8 @@ void program_execute(struct ProgramConcat *prg)
     switch (opcode)
     {
     case '<':
+      // NOTE: We're doing a safe subtraction here, but maybe we should
+      // terminate execution if subtraction will overflow?
       ctx.head0 = SAFE_SUB(ctx.head0, 1);
       ++ctx.ip;
       break;
@@ -113,6 +115,8 @@ void program_execute(struct ProgramConcat *prg)
       ++ctx.ip;
       break;
     case '{':
+      // NOTE: We're doing a safe subtraction here, but maybe we should
+      // terminate execution if subtraction will overflow?
       ctx.head1 = SAFE_SUB(ctx.head1, 1);
       ++ctx.ip;
       break;