From 0b7eee6e61bb23db89c55bc40b77f12ec2369d93 Mon Sep 17 00:00:00 2001
From: Slava Pestov <slava@slava-pestovs-macbook-pro.local>
Date: Sat, 9 May 2009 20:24:32 -0500
Subject: [PATCH] Slightly more space-efficient dispatch table representation

---
 core/generic/single/single.factor |  2 +-
 vm/dispatch.cpp                   | 11 +++++------
 2 files changed, 6 insertions(+), 7 deletions(-)

diff --git a/core/generic/single/single.factor b/core/generic/single/single.factor
index 36a76153f9..8d84b21bf7 100644
--- a/core/generic/single/single.factor
+++ b/core/generic/single/single.factor
@@ -163,7 +163,7 @@ M: hi-tag-dispatch-engine compile-engine
 
 : build-fast-hash ( methods -- buckets )
     >alist V{ } clone [ hashcode 1array ] distribute-buckets
-    [ compile-engines* >alist >array ] map ;
+    [ compile-engines* >alist { } join ] map ;
 
 M: echelon-dispatch-engine compile-engine
     dup n>> 0 = [
diff --git a/vm/dispatch.cpp b/vm/dispatch.cpp
index 847a19d738..4a1411733e 100755
--- a/vm/dispatch.cpp
+++ b/vm/dispatch.cpp
@@ -8,15 +8,14 @@ cell megamorphic_cache_misses;
 
 static cell search_lookup_alist(cell table, cell klass)
 {
-	array *pairs = untag<array>(table);
-	fixnum index = array_capacity(pairs) - 1;
+	array *elements = untag<array>(table);
+	fixnum index = array_capacity(elements) - 2;
 	while(index >= 0)
 	{
-		array *pair = untag<array>(array_nth(pairs,index));
-		if(array_nth(pair,0) == klass)
-			return array_nth(pair,1);
+		if(array_nth(elements,index) == klass)
+			return array_nth(elements,index + 1);
 		else
-			index--;
+			index -= 2;
 	}
 
 	return F;