Ensure we are not executing zero vectors

1 files changed, 4 insertions, 0 deletions

diff --git a/src/uxn-core.s b/src/uxn-core.s
index 362f0d4..7d73b18 100644
--- a/src/uxn-core.s
+++ b/src/uxn-core.s
@@ -27,6 +27,10 @@ rst_ptr: .word rst
 @
 .global uxn_eval_asm
 uxn_eval_asm:
+    @ Ensure PC is not null.
+    cmp     r0, #0
+    bxeq    lr
+
     @ Initialization.
     push    {r4-r7}
     ldr     r1, wst_ptr