Add 16x16->32 word Comba multiply and square

1 files changed, 67 insertions, 63 deletions

diff --git a/src/mp_karat.cpp b/src/mp_karat.cpp
index 770846b4e..15b0551fd 100644
--- a/src/mp_karat.cpp
+++ b/src/mp_karat.cpp
@@ -17,13 +17,13 @@ namespace {
 void karatsuba_mul(word z[], const word x[], const word y[], u32bit N,
                    word workspace[])
    {
-   const u32bit KARATSUBA_MUL_LOWER_SIZE = BOTAN_KARAT_MUL_THRESHOLD;
-
    if(N == 6)
       bigint_comba_mul6(z, x, y);
    else if(N == 8)
       bigint_comba_mul8(z, x, y);
-   else if(N < KARATSUBA_MUL_LOWER_SIZE || N % 2)
+   else if(N == 16)
+      bigint_comba_mul16(z, x, y);
+   else if(N < BOTAN_KARAT_MUL_THRESHOLD || N % 2)
       bigint_simple_mul(z, x, N, y, N);
    else
       {
@@ -96,13 +96,13 @@ void karatsuba_mul(word z[], const word x[], const word y[], u32bit N,
 *************************************************/
 void karatsuba_sqr(word z[], const word x[], u32bit N, word workspace[])
    {
-   const u32bit KARATSUBA_SQR_LOWER_SIZE = BOTAN_KARAT_SQR_THRESHOLD;
-
    if(N == 6)
       bigint_comba_sqr6(z, x);
    else if(N == 8)
       bigint_comba_sqr8(z, x);
-   else if(N < KARATSUBA_SQR_LOWER_SIZE || N % 2)
+   else if(N == 16)
+      bigint_comba_sqr16(z, x);
+   else if(N < BOTAN_KARAT_SQR_THRESHOLD || N % 2)
       bigint_simple_sqr(z, x, N);
    else
       {
@@ -234,97 +234,101 @@ u32bit karatsuba_size(u32bit z_size, u32bit x_size, u32bit x_sw)
    return 0;
    }
 
+}
+
 /*************************************************
-* Handle small operand multiplies                *
+* Multiplication Algorithm Dispatcher            *
 *************************************************/
-void handle_small_mul(word z[], u32bit z_size,
-                      const word x[], u32bit x_size, u32bit x_sw,
-                      const word y[], u32bit y_size, u32bit y_sw)
+void bigint_mul(word z[], u32bit z_size, word workspace[],
+                const word x[], u32bit x_size, u32bit x_sw,
+                const word y[], u32bit y_size, u32bit y_sw)
    {
-   if(x_sw == 1)        bigint_linmul3(z, y, y_sw, x[0]);
-   else if(y_sw == 1)   bigint_linmul3(z, x, x_sw, y[0]);
-
+   if(x_sw == 1)
+      {
+      bigint_linmul3(z, y, y_sw, x[0]);
+      }
+   else if(y_sw == 1)
+      {
+      bigint_linmul3(z, x, x_sw, y[0]);
+      }
    else if(x_sw <= 4 && x_size >= 4 &&
            y_sw <= 4 && y_size >= 4 && z_size >= 8)
+      {
       bigint_comba_mul4(z, x, y);
-
+      }
    else if(x_sw <= 6 && x_size >= 6 &&
            y_sw <= 6 && y_size >= 6 && z_size >= 12)
+      {
       bigint_comba_mul6(z, x, y);
-
+      }
    else if(x_sw <= 8 && x_size >= 8 &&
            y_sw <= 8 && y_size >= 8 && z_size >= 16)
+      {
       bigint_comba_mul8(z, x, y);
-
-   else
+      }
+   else if(x_sw <= 16 && x_size >= 16 &&
+           y_sw <= 16 && y_size >= 16 && z_size >= 32)
+      {
+      bigint_comba_mul16(z, x, y);
+      }
+   else if(x_sw < BOTAN_KARAT_MUL_THRESHOLD || y_sw < BOTAN_KARAT_MUL_THRESHOLD)
       bigint_simple_mul(z, x, x_sw, y, y_sw);
+   else
+      {
+      const u32bit N = karatsuba_size(z_size, x_size, x_sw, y_size, y_sw);
+
+      if(N)
+         {
+         clear_mem(workspace, 2*N);
+         karatsuba_mul(z, x, y, N, workspace);
+         }
+      else
+         bigint_simple_mul(z, x, x_sw, y, y_sw);
+      }
    }
 
 /*************************************************
-* Handle small operand squarings                 *
+* Squaring Algorithm Dispatcher                  *
 *************************************************/
-void handle_small_sqr(word z[], u32bit z_size,
-                      const word x[], u32bit x_size, u32bit x_sw)
+void bigint_sqr(word z[], u32bit z_size, word workspace[],
+                const word x[], u32bit x_size, u32bit x_sw)
    {
    if(x_sw == 1)
+      {
       bigint_linmul3(z, x, x_sw, x[0]);
+      }
    else if(x_sw <= 4 && x_size >= 4 && z_size >= 8)
+      {
       bigint_comba_sqr4(z, x);
+      }
    else if(x_sw <= 6 && x_size >= 6 && z_size >= 12)
+      {
       bigint_comba_sqr6(z, x);
+      }
    else if(x_sw <= 8 && x_size >= 8 && z_size >= 16)
+      {
       bigint_comba_sqr8(z, x);
-   else
-      bigint_simple_sqr(z, x, x_sw);
-   }
-
-}
-
-/*************************************************
-* Multiplication Algorithm Dispatcher            *
-*************************************************/
-void bigint_mul(word z[], u32bit z_size, word workspace[],
-                const word x[], u32bit x_size, u32bit x_sw,
-                const word y[], u32bit y_size, u32bit y_sw)
-   {
-   if(x_size <= 8 || y_size <= 8)
+      }
+   else if(x_sw <= 16 && x_size >= 16 && z_size >= 32)
       {
-      handle_small_mul(z, z_size, x, x_size, x_sw, y, y_size, y_sw);
-      return;
+      bigint_comba_sqr16(z, x);
       }
-
-   const u32bit N = karatsuba_size(z_size, x_size, x_sw, y_size, y_sw);
-
-   if(N)
+   else if(x_size < BOTAN_KARAT_SQR_THRESHOLD)
       {
-      clear_mem(workspace, 2*N);
-      karatsuba_mul(z, x, y, N, workspace);
+      bigint_simple_sqr(z, x, x_sw);
       }
    else
-      bigint_simple_mul(z, x, x_sw, y, y_sw);
-   }
-
-/*************************************************
-* Squaring Algorithm Dispatcher                  *
-*************************************************/
-void bigint_sqr(word z[], u32bit z_size, word workspace[],
-                const word x[], u32bit x_size, u32bit x_sw)
-   {
-   if(x_size <= 8 || x_sw <= 8)
       {
-      handle_small_sqr(z, z_size, x, x_size, x_sw);
-      return;
-      }
-
-   const u32bit N = karatsuba_size(z_size, x_size, x_sw);
+      const u32bit N = karatsuba_size(z_size, x_size, x_sw);
 
-   if(N)
-      {
-      clear_mem(workspace, 2*N);
-      karatsuba_sqr(z, x, N, workspace);
+      if(N)
+         {
+         clear_mem(workspace, 2*N);
+         karatsuba_sqr(z, x, N, workspace);
+         }
+      else
+         bigint_simple_sqr(z, x, x_sw);
       }
-   else
-      bigint_simple_sqr(z, x, x_sw);
    }
 
 }