From 9ebd6c11adf07d8b74e20603321367bfa0d218dd Mon Sep 17 00:00:00 2001
From: Doug Coleman <doug.coleman@gmail.com>
Date: Tue, 18 Sep 2012 17:14:31 -0700
Subject: [PATCH] cpu.x86: Fix the popcnt? word alien-assembly. XOR the
 return-reg RAX before calling BT/BSET because XOR clears the CF and the whole
 thing becomes a no-op. Change popcnt instruction to opt-out rather than
 opt-in. Fixes #663.

---
 basis/cpu/x86/features/features.factor | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/basis/cpu/x86/features/features.factor b/basis/cpu/x86/features/features.factor
index 7c4026bb6b..8be47f088c 100644
--- a/basis/cpu/x86/features/features.factor
+++ b/basis/cpu/x86/features/features.factor
@@ -88,13 +88,13 @@ MEMO: sse-version ( -- n )
     bool { } cdecl [
         return-reg 1 MOV
         CPUID
-        ECX 23 BT
         return-reg dup XOR
+        ECX 23 BT
         return-reg SETB
     ] alien-assembly ;
 
 MEMO: enable-popcnt? ( -- ? )
-    popcnt? "enable-popcnt" get and ;
+    popcnt? "disable-popcnt" get not and ;
 
 [ { sse-version enable-popcnt? } [ reset-memoized ] each ]
 "cpu.x86.features" add-startup-hook