Add (untested) support for VC++'s _umul128 intrinsic, which apparently

works on both x86-64 and ia64. Will allow using 64-bit limbs on Windows.

2 files changed, 76 insertions, 0 deletions

diff --git a/src/math/bigint/mp_amd64_msvc/info.txt b/src/math/bigint/mp_amd64_msvc/info.txt
new file mode 100644
index 000000000..b6f322b83
--- /dev/null
+++ b/src/math/bigint/mp_amd64_msvc/info.txt
@@ -0,0 +1,16 @@
+load_on dep
+
+mp_bits 64
+
+<header:internal>
+mp_asm.h
+</header:internal>
+
+<arch>
+amd64
+ia64
+</arch>
+
+<cc>
+msvc
+</cc>
diff --git a/src/math/bigint/mp_amd64_msvc/mp_asm.h b/src/math/bigint/mp_amd64_msvc/mp_asm.h
new file mode 100644
index 000000000..09ca303df
--- /dev/null
+++ b/src/math/bigint/mp_amd64_msvc/mp_asm.h
@@ -0,0 +1,60 @@
+/*
+* Multiply-Add for 64-bit MSVC
+* (C) 2010 Jack Lloyd
+*
+* Distributed under the terms of the Botan license
+*/
+
+#ifndef BOTAN_MP_ASM_H__
+#define BOTAN_MP_ASM_H__
+
+#include <botan/mp_types.h>
+
+#if (BOTAN_MP_WORD_BITS != 64)
+   #error The mp_amd64_msvc module requires that BOTAN_MP_WORD_BITS == 64
+#endif
+
+#pragma intrinsic(_umul128)
+
+namespace Botan {
+
+extern "C" {
+
+/*
+* Word Multiply
+*/
+inline word word_madd2(word a, word b, word* c)
+   {
+   word hi, lo;
+   lo = _umul128(a, b, &hi);
+
+   lo += *c;
+   hi += (lo < *c); // carry?
+
+   *c = hi;
+   return lo;
+   }
+
+/*
+* Word Multiply/Add
+*/
+inline word word_madd3(word a, word b, word c, word* d)
+   {
+   word hi, lo;
+   lo = _umul128(a, b, &hi);
+
+   lo += c;
+   hi += (lo < c); // carry?
+
+   lo += *d;
+   hi += (lo < *d); // carry?
+
+   *d = hi;
+   return lo;
+   }
+
+}
+
+}
+
+#endif