1 files changed, 49 insertions, 0 deletions
diff --git a/src/mp_monty.cpp b/src/mp_monty.cpp
new file mode 100644
index 000000000..03f6f966b
--- /dev/null
+++ b/src/mp_monty.cpp
@@ -0,0 +1,49 @@
+/*************************************************
+* Montgomery Reduction Source File               *
+* (C) 1999-2006 The Botan Project                *
+*************************************************/
+
+#include <botan/mp_asm.h>
+#include <botan/mp_asmi.h>
+#include <botan/mp_core.h>
+
+namespace Botan {
+
+extern "C" {
+
+/*************************************************
+* Montgomery Reduction Algorithm                 *
+*************************************************/
+void bigint_monty_redc(word z[], u32bit z_size,
+                       const word x[], u32bit x_size, word u)
+   {
+   for(u32bit j = 0; j != x_size; ++j)
+      {
+      word* z_j = z + j;
+
+      const word y = z_j[0] * u;
+      word carry = 0;
+
+      const u32bit blocks = x_size - (x_size % 8);
+
+      for(u32bit k = 0; k != blocks; k += 8)
+         carry = word8_madd3(z_j + k, x + k, y, carry);
+
+      for(u32bit k = blocks; k != x_size; ++k)
+         z_j[k] = word_madd3(x[k], y, z_j[k], carry, &carry);
+
+      word carry2 = 0;
+      z_j[x_size] = word_add(z_j[x_size], carry, &carry2);
+      carry = carry2;
+
+      for(u32bit k = x_size + 1; carry && k != z_size - j; ++k)
+         {
+         ++z_j[k];
+         carry = !z_j[k];
+         }
+      }
+   }
+
+}
+
+}