From 3331382e7c198b9080389a60742e5eb508032466 Mon Sep 17 00:00:00 2001
From: sof <unknown>
Date: Mon, 24 Nov 1997 21:12:32 +0000
Subject: [PATCH] [project @ 1997-11-24 21:12:32 by sof] Stack underflow
comment added
---
ghc/runtime/main/StgUpdate.lhc | 8 ++++++++
1 file changed, 8 insertions(+)
diff --git a/ghc/runtime/main/StgUpdate.lhc b/ghc/runtime/main/StgUpdate.lhc
index e5c669082dec..e91a16943813 100644
--- a/ghc/runtime/main/StgUpdate.lhc
+++ b/ghc/runtime/main/StgUpdate.lhc
@@ -674,6 +674,14 @@ STGFUN(PAP_entry)
FB_
+ /* Concurrent World:
+ If we come from StackUnderflowEnterNode the old StkO has been
+ nuked and the PAP carries over data from the old StkO.
+ The underflow code must restore RetReg to the right value
+ because it is not grabbed from the update frame if there is data
+ on one of the two stacks.
+ -- HWL
+ */
while (AREL(SuA - SpA) == 0 && BREL(SuB - SpB) == 0) {
#ifdef CONCURRENT
if (SuB < STKO_BSTK_BOT(StkOReg)) {
--
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