diff --git a/subx/056trace.subx b/subx/056trace.subx
index c60b9f17..aea4a135 100644
--- a/subx/056trace.subx
+++ b/subx/056trace.subx
@@ -553,7 +553,8 @@ $skip-next-line:loop:
     39/compare                      3/mod/direct    1/rm32/ECX    .           .             .           3/r32/EBX   .               .                 # compare ECX and EBX
     7d/jump-if-greater-or-equal  $skip-next-line:end/disp8
     # if (*curr/ECX == '\n') break
-    8b/copy                         0/mod/indirect  1/rm32/ECX    .           .             .           0/r32/EAX   .               .                 # copy *ECX to EAX
+    31/xor                          3/mod/direct    0/rm32/EAX    .           .             .           0/r32/EAX   .               .                 # clear EAX
+    8a/copy-byte                    0/mod/indirect  1/rm32/ECX    .           .             .           0/r32/EAX   .               .                 # copy *ECX to EAX
     3d/compare-EAX-and  0a/imm32/newline
     74/jump-if-equal  $skip-next-line:end/disp8
     # ++curr/ECX