From 5b09b37f81e014433061cec869d8310547dfaadd Mon Sep 17 00:00:00 2001
From: Andy Wingo <wingo@pobox.com>
Date: Fri, 11 Dec 2009 11:17:03 +0100
Subject: [PATCH] vm: handle interrupts on backwards jumps

* libguile/vm-i-system.c (BR, br): Handle interrupts on backwards jumps,
  so we can Ctrl-C an endless loop.
---
 libguile/vm-i-system.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/libguile/vm-i-system.c b/libguile/vm-i-system.c
index 8eaf59cb6..41874fae3 100644
--- a/libguile/vm-i-system.c
+++ b/libguile/vm-i-system.c
@@ -466,6 +466,8 @@ VM_DEFINE_INSTRUCTION (34, long_toplevel_set, "long-toplevel-set", 2, 1, 0)
   FETCH_OFFSET (offset);                        \
   if (p)					\
     ip += offset;                               \
+  if (offset < 0)                               \
+    VM_HANDLE_INTERRUPTS;                       \
   NULLSTACK (1);				\
   DROP ();					\
   NEXT;						\
@@ -476,6 +478,8 @@ VM_DEFINE_INSTRUCTION (35, br, "br", 3, 0, 0)
   scm_t_int32 offset;
   FETCH_OFFSET (offset);
   ip += offset;
+  if (offset < 0)
+    VM_HANDLE_INTERRUPTS;
   NEXT;
 }