Add a version for x86-64 in mp_asm64, though it is disabled by default

because the dependency handling/module picker gets confused otherwise.
This allows building a mostly C++ version with 64-bit words with only a
very small amount of inline asm (which is good for debugging the asm).

2 files changed, 8 insertions, 0 deletions

diff --git a/src/math/bigint/mp_asm64/info.txt b/src/math/bigint/mp_asm64/info.txt
index 85a4391b9..5c112c490 100644
--- a/src/math/bigint/mp_asm64/info.txt
+++ b/src/math/bigint/mp_asm64/info.txt
@@ -10,6 +10,7 @@ mp_generic:mp_asmi.h
 </add>
 
 <arch>
+#amd64
 alpha
 ia64
 mips64
diff --git a/src/math/bigint/mp_asm64/mp_asm.h b/src/math/bigint/mp_asm64/mp_asm.h
index e455b3616..f751a50f8 100644
--- a/src/math/bigint/mp_asm64/mp_asm.h
+++ b/src/math/bigint/mp_asm64/mp_asm.h
@@ -21,6 +21,13 @@ namespace Botan {
    z1 = a * b;                                           \
 } while(0);
 
+#elif defined(BOTAN_TARGET_ARCH_IS_AMD64)
+
+#define BOTAN_WORD_MUL(a,b,z1,z0) do {       \
+   asm("mulq %3" : "=d" (z0), "=a" (z1) :    \
+       "a" (a), "rm" (b) : "cc");            \
+} while(0);
+
 #elif defined(BOTAN_TARGET_ARCH_IS_IA64)
 
 #define BOTAN_WORD_MUL(a,b,z1,z0) do {                     \