X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fmisc.h;h=373f1b77c76ed0fbdf6a912abf267ad4703a6ef0;hp=05bfc7de4d56906bb436d3bfe634c4e8dce4284b;hb=bf5ce1c214f8f8e3f98e5e3ac43db0dd28617e35;hpb=beb327f910ed782f358d69201643ccd99b982a48

diff --git a/src/misc.h b/src/misc.h
index 05bfc7de..373f1b77 100644
--- a/src/misc.h
+++ b/src/misc.h
@@ -110,6 +110,19 @@ public:
   { return T(rand64() & rand64() & rand64()); }
 };
 
+inline uint64_t mul_hi64(uint64_t a, uint64_t b) {
+#if defined(__GNUC__) && defined(IS_64BIT)
+    __extension__ typedef unsigned __int128 uint128;
+    return ((uint128)a * (uint128)b) >> 64;
+#else
+    uint64_t aL = (uint32_t)a, aH = a >> 32;
+    uint64_t bL = (uint32_t)b, bH = b >> 32;
+    uint64_t c1 = (aL * bL) >> 32;
+    uint64_t c2 = aH * bL + c1;
+    uint64_t c3 = aL * bH + (uint32_t)c2;
+    return aH * bH + (c2 >> 32) + (c3 >> 32);
+#endif
+}
 
 /// Under Windows it is not possible for a process to run on more than one
 /// logical processor group. This usually means to be limited to use max 64