Cache the Modular_Reducer of p in CurveGFp; speedup of 3-4x

2 files changed, 11 insertions, 8 deletions

diff --git a/src/math/gfpmath/curve_gfp.h b/src/math/gfpmath/curve_gfp.h
index cc1d42290..6010183b8 100644
--- a/src/math/gfpmath/curve_gfp.h
+++ b/src/math/gfpmath/curve_gfp.h
@@ -10,7 +10,7 @@
 #ifndef BOTAN_GFP_CURVE_H__
 #define BOTAN_GFP_CURVE_H__
 
-#include <botan/bigint.h>
+#include <botan/numthry.h>
 
 namespace Botan {
 
@@ -28,7 +28,7 @@ class BOTAN_DLL CurveGFp
       * @param b second coefficient
       */
       CurveGFp(const BigInt& p, const BigInt& a, const BigInt& b) :
-         p(p), a(a), b(b) {}
+         p(p), a(a), b(b), reducer_p(p) {}
 
       // CurveGFp(const CurveGFp& other) = default;
       // CurveGFp& operator=(const CurveGFp& other) = default;
@@ -51,6 +51,8 @@ class BOTAN_DLL CurveGFp
       */
       const BigInt& get_p() const { return p; }
 
+      const Modular_Reducer& mod_p() const { return reducer_p; }
+
       /**
       * swaps the states of *this and other, does not throw
       * @param other The curve to swap values with
@@ -69,6 +71,7 @@ class BOTAN_DLL CurveGFp
 
    private:
       BigInt p, a, b;
+      Modular_Reducer reducer_p;
    };
 
 inline bool operator!=(const CurveGFp& lhs, const CurveGFp& rhs)
diff --git a/src/math/gfpmath/point_gfp.cpp b/src/math/gfpmath/point_gfp.cpp
index dc55e2fa6..c28b1eb62 100644
--- a/src/math/gfpmath/point_gfp.cpp
+++ b/src/math/gfpmath/point_gfp.cpp
@@ -50,7 +50,7 @@ PointGFp& PointGFp::operator+=(const PointGFp& rhs)
       return *this;
       }
 
-   Modular_Reducer mod_p(curve.get_p());
+   const Modular_Reducer& mod_p = curve.mod_p();
 
    BigInt rhs_z2 = mod_p.square(rhs.coord_z);
    BigInt U1 = mod_p.multiply(coord_x, rhs_z2);
@@ -148,7 +148,7 @@ PointGFp& PointGFp::operator*=(const BigInt& scalar)
       */
       if(H.coord_z != 1)
          {
-         Modular_Reducer mod_p(curve.get_p());
+         const Modular_Reducer& mod_p = curve.mod_p();
 
          BigInt z_inv = inverse_mod(H.coord_z, curve.get_p());
 
@@ -183,7 +183,7 @@ void PointGFp::mult2_in_place()
       return;
       }
 
-   Modular_Reducer mod_p(curve.get_p());
+   const Modular_Reducer& mod_p = curve.mod_p();
 
    BigInt y_2 = mod_p.square(coord_y);
 
@@ -216,7 +216,7 @@ BigInt PointGFp::get_affine_x() const
    if(is_zero())
       throw Illegal_Transformation("cannot convert to affine");
 
-   Modular_Reducer mod_p(curve.get_p());
+   const Modular_Reducer& mod_p = curve.mod_p();
 
    BigInt z2 = mod_p.square(coord_z);
    return mod_p.multiply(coord_x, inverse_mod(z2, curve.get_p()));
@@ -227,7 +227,7 @@ BigInt PointGFp::get_affine_y() const
    if(is_zero())
       throw Illegal_Transformation("cannot convert to affine");
 
-   Modular_Reducer mod_p(curve.get_p());
+   const Modular_Reducer& mod_p = curve.mod_p();
 
    BigInt z3 = mod_p.multiply(coord_z, mod_p.square(coord_z));
    return mod_p.multiply(coord_y, inverse_mod(z3, curve.get_p()));
@@ -251,7 +251,7 @@ void PointGFp::check_invariants() const
    if(is_zero())
       return;
 
-   Modular_Reducer mod_p(curve.get_p());
+   const Modular_Reducer& mod_p = curve.mod_p();
 
    BigInt y2 = mod_p.square(coord_y);
    BigInt x3 = mod_p.multiply(coord_x, mod_p.square(coord_x));