1 files changed, 77 insertions, 0 deletions
diff --git a/src/math/mp/mp_mulop.cpp b/src/math/mp/mp_mulop.cpp
new file mode 100644
index 000000000..e6a8ba891
--- /dev/null
+++ b/src/math/mp/mp_mulop.cpp
@@ -0,0 +1,77 @@
+/*
+* Simple O(N^2) Multiplication and Squaring
+* (C) 1999-2008 Jack Lloyd
+*
+* Distributed under the terms of the Botan license
+*/
+
+#include <botan/internal/mp_core.h>
+#include <botan/internal/mp_asm.h>
+#include <botan/internal/mp_asmi.h>
+#include <botan/mem_ops.h>
+
+namespace Botan {
+
+extern "C" {
+
+/*
+* Simple O(N^2) Multiplication
+*/
+void bigint_simple_mul(word z[], const word x[], size_t x_size,
+                                 const word y[], size_t y_size)
+   {
+   const size_t x_size_8 = x_size - (x_size % 8);
+
+   clear_mem(z, x_size + y_size);
+
+   for(size_t i = 0; i != y_size; ++i)
+      {
+      const word y_i = y[i];
+
+      word carry = 0;
+
+      for(size_t j = 0; j != x_size_8; j += 8)
+         carry = word8_madd3(z + i + j, x + j, y_i, carry);
+
+      for(size_t j = x_size_8; j != x_size; ++j)
+         z[i+j] = word_madd3(x[j], y_i, z[i+j], &carry);
+
+      z[x_size+i] = carry;
+      }
+   }
+
+/*
+* Simple O(N^2) Squaring
+*
+* This is exactly the same algorithm as bigint_simple_mul, however
+* because C/C++ compilers suck at alias analysis it is good to have
+* the version where the compiler knows that x == y
+*
+* There is an O(n^1.5) squaring algorithm specified in Handbook of
+* Applied Cryptography, chapter 14
+*
+*/
+void bigint_simple_sqr(word z[], const word x[], size_t x_size)
+   {
+   const size_t x_size_8 = x_size - (x_size % 8);
+
+   clear_mem(z, 2*x_size);
+
+   for(size_t i = 0; i != x_size; ++i)
+      {
+      const word x_i = x[i];
+      word carry = 0;
+
+      for(size_t j = 0; j != x_size_8; j += 8)
+         carry = word8_madd3(z + i + j, x + j, x_i, carry);
+
+      for(size_t j = x_size_8; j != x_size; ++j)
+         z[i+j] = word_madd3(x[j], x_i, z[i+j], &carry);
+
+      z[x_size+i] = carry;
+      }
+   }
+
+}
+
+}