From 007ee2a4d8f3b87779599f06512973c92d0640e8 Mon Sep 17 00:00:00 2001
From: Tim Vaughan <tgvaughan@gmail.com>
Date: Tue, 20 Dec 2016 07:50:27 +1300
Subject: [PATCH] Implemented fix:gcd.

---
 src/scheme-primitives.4th | 17 ++++++++++++++++-
 1 file changed, 16 insertions(+), 1 deletion(-)

diff --git a/src/scheme-primitives.4th b/src/scheme-primitives.4th
index 5ec154b..7e123f7 100644
--- a/src/scheme-primitives.4th
+++ b/src/scheme-primitives.4th
@@ -223,12 +223,27 @@
     swap abs swap
 ; 1 make-fa-primitive fix:abs
 
+: sort-pair
+    2dup > if
+        swap
+    then
+;
 
 ( Find the GCD of n1 and n2 where n2 < n1. )
 : gcd ( n1 n2 -- m )
-    
+    sort-pair
+    over 0= if
+        swap drop
+    else
+        over mod
+        recurse
+    then
 ;
 
+:noname ( fixnum fixnum -- fixnum' )
+    drop swap drop gcd fixnum-type
+; 2 make-fa-primitive fix:gcd
+
 \ --- Flonums ---
 
 :noname ( flonum flonum -- bool )
-- 
2.20.1