From a8bed10f62f255fa9f1983c780de27333b691551 Mon Sep 17 00:00:00 2001
From: Camil Staps
Date: Sat, 15 Oct 2016 11:30:34 +0200
Subject: log

---
 log.md | 18 ++++++++++++++++++
 1 file changed, 18 insertions(+)

diff --git a/log.md b/log.md
index 7750feb..fb61cdc 100644
--- a/log.md
+++ b/log.md
@@ -202,3 +202,21 @@ garbage collector (`-gcc`), not with the marking/compacting garbage collector
 **Question**: It seems there are whole areas of the generated binaries that are
 all zero (like `file_table`, where you can expect that, but also e.g.
 `small_integers`, should this be zero as well?)
+
+### 2016-10-13
+
+The problem that the copying collector segfaults has to do with `thumb2copy.s`
+(rts). About this file:
+
+* `continue_after_selector_2`: checks with bit 1 if the node is in rnf and
+  jumps to `in_hnf_2` (`1`) or `not_in_hnf_2` (`0`) accordingly.
+* `not_in_hnf_2`: checks with bit 0 if the node has been copied to the other
+  semispace already. If so (`1`), it jumps to `already_copied_2`.
+
+The issue above arises due to the fact that `r6`, which holds the node address,
+has the lowest bit set. Hence, it isn't copied.
+
+### 2016-10-15
+
+As suggested by John on the 13th, this is temporarily fixed by settings the
+lowest bit to 0 manually (rts `887b38e`). Should be fixed properly.
-- 
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