Merge mp_word64 into mp_generic

Now 64-bit limbs can be used regardless of processor, though we
continue to use 32-bit unless we know the processor natively supports
64-bit operations.

5 files changed, 52 insertions, 95 deletions

diff --git a/src/math/mp/info.txt b/src/math/mp/info.txt
index 531eee4e4..8dcaa7481 100644
--- a/src/math/mp/info.txt
+++ b/src/math/mp/info.txt
@@ -19,5 +19,5 @@ mp_core.h
 </header:internal>
 
 <requires>
-mp_x86_64|mp_word64|mp_x86_32|mp_x86_32_msvc|mp_generic
+mp_x86_64|mp_x86_32|mp_x86_32_msvc|mp_generic
 </requires>
diff --git a/src/math/mp/mp_generic/mp_asm.h b/src/math/mp/mp_generic/mp_asm.h
index 08f40aa67..ff00cc24b 100644
--- a/src/math/mp/mp_generic/mp_asm.h
+++ b/src/math/mp/mp_generic/mp_asm.h
@@ -1,6 +1,6 @@
 /*
 * Lowest Level MPI Algorithms
-* (C) 1999-2008 Jack Lloyd
+* (C) 1999-2008,2013 Jack Lloyd
 *     2006 Luca Piccarreta
 *
 * Distributed under the terms of the Botan license
@@ -13,18 +13,6 @@
 
 namespace Botan {
 
-#if (BOTAN_MP_WORD_BITS == 8)
-  typedef u16bit dword;
-#elif (BOTAN_MP_WORD_BITS == 16)
-  typedef u32bit dword;
-#elif (BOTAN_MP_WORD_BITS == 32)
-  typedef u64bit dword;
-#elif (BOTAN_MP_WORD_BITS == 64)
-  #error BOTAN_MP_WORD_BITS can be 64 only with assembly support
-#else
-  #error BOTAN_MP_WORD_BITS must be 8, 16, 32, or 64
-#endif
-
 extern "C" {
 
 /*
@@ -32,9 +20,23 @@ extern "C" {
 */
 inline word word_madd2(word a, word b, word* c)
    {
-   dword z = (dword)a * b + *c;
-   *c = (word)(z >> BOTAN_MP_WORD_BITS);
-   return (word)z;
+#if defined(BOTAN_HAS_MP_DWORD)
+   const dword s = static_cast<dword>(a) * b + *c;
+   *c = static_cast<word>(s >> BOTAN_MP_WORD_BITS);
+   return static_cast<word>(s);
+#else
+   static_assert(BOTAN_MP_WORD_BITS == 64, "Unexpected word size");
+
+   word hi = 0, lo = 0;
+
+   mul64x64_128(a, b, &lo, &hi);
+
+   lo += *c;
+   hi += (lo < *c); // carry?
+
+   *c = hi;
+   return lo;
+#endif
    }
 
 /*
@@ -42,9 +44,26 @@ inline word word_madd2(word a, word b, word* c)
 */
 inline word word_madd3(word a, word b, word c, word* d)
    {
-   dword z = (dword)a * b + c + *d;
-   *d = (word)(z >> BOTAN_MP_WORD_BITS);
-   return (word)z;
+#if defined(BOTAN_HAS_MP_DWORD)
+   const dword s = static_cast<dword>(a) * b + c + *d;
+   *d = static_cast<word>(s >> BOTAN_MP_WORD_BITS);
+   return static_cast<word>(s);
+#else
+   static_assert(BOTAN_MP_WORD_BITS == 64, "Unexpected word size");
+
+   word hi = 0, lo = 0;
+
+   mul64x64_128(a, b, &lo, &hi);
+
+   lo += c;
+   hi += (lo < c); // carry?
+
+   lo += *d;
+   hi += (lo < *d); // carry?
+
+   *d = hi;
+   return lo;
+#endif
    }
 
 }
diff --git a/src/math/mp/mp_types.h b/src/math/mp/mp_types.h
index 1648713ed..60282fb83 100644
--- a/src/math/mp/mp_types.h
+++ b/src/math/mp/mp_types.h
@@ -9,17 +9,30 @@
 #define BOTAN_MPI_TYPES_H__
 
 #include <botan/types.h>
+#include <botan/mul128.h>
 
 namespace Botan {
 
 #if (BOTAN_MP_WORD_BITS == 8)
   typedef byte word;
+  typedef u16bit dword;
+  #define BOTAN_HAS_MP_DWORD
 #elif (BOTAN_MP_WORD_BITS == 16)
   typedef u16bit word;
+  typedef u32bit dword;
+  #define BOTAN_HAS_MP_DWORD
 #elif (BOTAN_MP_WORD_BITS == 32)
   typedef u32bit word;
+  typedef u64bit dword;
+  #define BOTAN_HAS_MP_DWORD
 #elif (BOTAN_MP_WORD_BITS == 64)
   typedef u64bit word;
+
+  #if defined(BOTAN_TARGET_HAS_NATIVE_UINT128)
+    typedef uint128_t dword;
+    #define BOTAN_HAS_MP_DWORD
+  #endif
+
 #else
   #error BOTAN_MP_WORD_BITS must be 8, 16, 32, or 64
 #endif
diff --git a/src/math/mp/mp_word64/info.txt b/src/math/mp/mp_word64/info.txt
deleted file mode 100644
index a12221f4e..000000000
--- a/src/math/mp/mp_word64/info.txt
+++ /dev/null
@@ -1,18 +0,0 @@
-mp_bits 64
-
-load_on dep
-
-<header:internal>
-mp_asm.h
-mp_generic:mp_asmi.h
-</header:internal>
-
-<arch>
-alpha
-ia64
-mips64
-ppc64
-s390x
-sparc64
-x86_64
-</arch>
diff --git a/src/math/mp/mp_word64/mp_asm.h b/src/math/mp/mp_word64/mp_asm.h
deleted file mode 100644
index 76d2bb918..000000000
--- a/src/math/mp/mp_word64/mp_asm.h
+++ /dev/null
@@ -1,57 +0,0 @@
-/*
-* MPI Multiply-Add Core
-* (C) 1999-2007 Jack Lloyd
-*
-* Distributed under the terms of the Botan license
-*/
-
-#ifndef BOTAN_MP_MADD_H__
-#define BOTAN_MP_MADD_H__
-
-#include <botan/mp_types.h>
-#include <botan/internal/mul128.h>
-
-namespace Botan {
-
-#if (BOTAN_MP_WORD_BITS != 64)
-   #error The mp_word64 module requires that BOTAN_MP_WORD_BITS == 64
-#endif
-
-/*
-* Word Multiply/Add
-*/
-inline word word_madd2(word a, word b, word* c)
-   {
-   word z0 = 0, z1 = 0;
-
-   mul64x64_128(a, b, &z1, &z0);
-
-   z1 += *c;
-   z0 += (z1 < *c);
-
-   *c = z0;
-   return z1;
-   }
-
-/*
-* Word Multiply/Add
-*/
-inline word word_madd3(word a, word b, word c, word* d)
-   {
-   word z0 = 0, z1 = 0;
-
-   mul64x64_128(a, b, &z1, &z0);
-
-   z1 += c;
-   z0 += (z1 < c);
-
-   z1 += *d;
-   z0 += (z1 < *d);
-
-   *d = z0;
-   return z1;
-   }
-
-}
-
-#endif