From 64f037d91e0c9296dcaef9a0ff3eb33b19a2ed34 Mon Sep 17 00:00:00 2001
From: Bryan Newbold <bnewbold@robocracy.org>
Date: Mon, 20 Feb 2017 00:05:38 -0800
Subject: Import Upstream version 3a5

---
 modular.scm | 44 +++++++++++++++++++++++---------------------
 1 file changed, 23 insertions(+), 21 deletions(-)

(limited to 'modular.scm')

diff --git a/modular.scm b/modular.scm
index e77ced4..78c78bb 100644
--- a/modular.scm
+++ b/modular.scm
@@ -185,32 +185,34 @@
       (lambda (m a b)
 	(define a0 a)
 	(define p 0)
-	
 	(cond
 	 ((zero? m) (* a b))
 	 ((negative? m)
 	  ;; Need algorighm to work with symmetric representation.
-	  (modular:normalize m (* a b)))
+	  (modular:normalize m (* (modular:normalize m a)
+				  (modular:normalize m b))))
 	 (else
-	  (cond
-	   ((< a modular:r))
-	   ((< b modular:r) (set! a b) (set! b a0) (set! a0 a))
-	   (else
-	    (set! a0 (modulo a modular:r))
-	    (let ((a1 (quotient a modular:r))
-		  (qh (quotient m modular:r))
-		  (rh (modulo m modular:r)))
-	      (cond ((>= a1 modular:r)
-		     (set! a1 (- a1 modular:r))
-		     (set! p (modulo (- (* modular:r (modulo b qh))
-					(* (quotient b qh) rh)) m))))
-	      (cond ((not (zero? a1))
-		     (let ((q (quotient m a1)))
-		       (set! p (- p (* (quotient b q) (modulo m a1))))
-		       (set! p (modulo (+ (if (positive? p) (- p m) p)
-					  (* a1 (modulo b q))) m)))))
-	      (set! p (modulo (- (* modular:r (modulo p qh))
-				 (* (quotient p qh) rh)) m)))))
+	  (set! a (modulo a m))
+	  (set! b (modulo b m))
+	  (set! a0 a)
+	  (cond ((< a modular:r))
+		((< b modular:r) (set! a b) (set! b a0) (set! a0 a))
+		(else
+		 (set! a0 (modulo a modular:r))
+		 (let ((a1 (quotient a modular:r))
+		       (qh (quotient m modular:r))
+		       (rh (modulo m modular:r)))
+		   (cond ((>= a1 modular:r)
+			  (set! a1 (- a1 modular:r))
+			  (set! p (modulo (- (* modular:r (modulo b qh))
+					     (* (quotient b qh) rh)) m))))
+		   (cond ((not (zero? a1))
+			  (let ((q (quotient m a1)))
+			    (set! p (- p (* (quotient b q) (modulo m a1))))
+			    (set! p (modulo (+ (if (positive? p) (- p m) p)
+					       (* a1 (modulo b q))) m)))))
+		   (set! p (modulo (- (* modular:r (modulo p qh))
+				      (* (quotient p qh) rh)) m)))))
 	  (if (zero? a0)
 	      p
 	      (let ((q (quotient m a0)))
-- 
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