From 1b4072de538b9680663022c3bb5c0e9b6176fa14 Mon Sep 17 00:00:00 2001
From: Mike Hamburg <mike@shiftleft.org>
Date: Thu, 22 Jan 2015 17:53:13 -0800
Subject: [PATCH] fix(?) perf regression in monty_aux_step

---
 src/ec_point.c | 18 ++++++++++--------
 1 file changed, 10 insertions(+), 8 deletions(-)

diff --git a/src/ec_point.c b/src/ec_point.c
index bb552f8..1a61051 100644
--- a/src/ec_point.c
+++ b/src/ec_point.c
@@ -258,21 +258,23 @@ void
 montgomery_aux_step (
     struct montgomery_aux_t* a
 ) {
-    field_add ( a->xs, a->xa, a->za ); 
-    field_sub ( a->zs, a->xa, a->za ); 
-    field_add ( a->xa, a->xd, a->zd ); 
-    field_sub ( a->za, a->xd, a->zd ); 
+    ANALYZE_THIS_ROUTINE_CAREFULLY;
+    field_add_nr ( a->xs, a->xa, a->za ); 
+    field_subx_nr ( a->zs, a->xa, a->za ); 
+    field_add_nr ( a->xa, a->xd, a->zd ); 
+    field_subx_nr ( a->za, a->xd, a->zd ); 
     field_mul ( a->xd, a->xa, a->zs ); 
     field_mul ( a->zd, a->xs, a->za ); 
-    field_add ( a->xs, a->xd, a->zd ); 
-    field_sub ( a->zd, a->xd, a->zd ); 
+    field_add_nr ( a->xs, a->xd, a->zd ); 
+    field_subx_nr ( a->zd, a->xd, a->zd ); 
     field_mul ( a->zs, a->zd, a->s0 ); 
     field_sqr ( a->zd, a->xa );         
     field_sqr ( a->xa, a->za );         
-    field_sub ( a->za, a->zd, a->xa ); 
+    field_subx_nr ( a->za, a->zd, a->xa ); 
+    IF32( field_weak_reduce( a->za ) );
     field_mul ( a->xd, a->xa, a->zd ); 
     field_mulw_scc_wr ( a->zd, a->xa, 1-EDWARDS_D ); 
-    field_add ( a->xa, a->za, a->zd ); 
+    field_add_nr ( a->xa, a->za, a->zd ); 
     field_mul ( a->zd, a->xa, a->za ); 
     field_sqr ( a->xa, a->xs );         
     field_sqr ( a->za, a->zs );