1 files changed, 92 insertions, 0 deletions
diff --git a/src/math/bigint/mp_misc.cpp b/src/math/bigint/mp_misc.cpp
new file mode 100644
index 000000000..db9c8cda0
--- /dev/null
+++ b/src/math/bigint/mp_misc.cpp
@@ -0,0 +1,92 @@
+/*************************************************
+* MP Misc Functions Source File                  *
+* (C) 1999-2008 Jack Lloyd                       *
+*************************************************/
+
+#include <botan/mp_core.h>
+#include <botan/mp_asm.h>
+
+namespace Botan {
+
+extern "C" {
+
+/*************************************************
+* Core Division Operation                        *
+*************************************************/
+u32bit bigint_divcore(word q, word y1, word y2,
+                      word x1, word x2, word x3)
+   {
+   word y0 = 0;
+   y2 = word_madd2(q, y2, &y0);
+   y1 = word_madd2(q, y1, &y0);
+
+   if(y0 > x1) return 1;
+   if(y0 < x1) return 0;
+   if(y1 > x2)  return 1;
+   if(y1 < x2)  return 0;
+   if(y2 > x3)  return 1;
+   if(y2 < x3)  return 0;
+   return 0;
+   }
+
+/*************************************************
+* Compare two MP integers                        *
+*************************************************/
+s32bit bigint_cmp(const word x[], u32bit x_size,
+                  const word y[], u32bit y_size)
+   {
+   if(x_size < y_size) { return (-bigint_cmp(y, y_size, x, x_size)); }
+
+   while(x_size > y_size)
+      {
+      if(x[x_size-1])
+         return 1;
+      x_size--;
+      }
+   for(u32bit j = x_size; j > 0; --j)
+      {
+      if(x[j-1] > y[j-1]) return 1;
+      if(x[j-1] < y[j-1]) return -1;
+      }
+   return 0;
+   }
+
+/*************************************************
+* Do a 2-word/1-word Division                    *
+*************************************************/
+word bigint_divop(word n1, word n0, word d)
+   {
+   word high = n1 % d, quotient = 0;
+
+   for(u32bit j = 0; j != MP_WORD_BITS; ++j)
+      {
+      word high_top_bit = (high & MP_WORD_TOP_BIT);
+
+      high <<= 1;
+      high |= (n0 >> (MP_WORD_BITS-1-j)) & 1;
+      quotient <<= 1;
+
+      if(high_top_bit || high >= d)
+         {
+         high -= d;
+         quotient |= 1;
+         }
+      }
+
+   return quotient;
+   }
+
+/*************************************************
+* Do a 2-word/1-word Modulo                      *
+*************************************************/
+word bigint_modop(word n1, word n0, word d)
+   {
+   word z = bigint_divop(n1, n0, d);
+   word dummy = 0;
+   z = word_madd2(z, d, &dummy);
+   return (n0-z);
+   }
+
+}
+
+}