[PATCH v3 4/7] include: Add a __shiftright128 intrinsic definition.

[Rémi Bernon]

From: Rémi Bernon

---
 include/msvcrt/intrin.h |  4 ++++
 include/winnt.h         | 12 ++++++++++++
 2 files changed, 16 insertions(+)

diff --git a/include/msvcrt/intrin.h b/include/msvcrt/intrin.h
index 03d856c5933..7d22f80ed81 100644
--- a/include/msvcrt/intrin.h
+++ b/include/msvcrt/intrin.h
@@ -90,6 +90,10 @@ unsigned __int64 __getReg(int);

#endif

+#if defined(_MSC_VER) && defined(__x86_64__)
+unsigned __int64 __shiftright128(unsigned __int64,unsigned __int64,unsigned char);
+#endif
+
 #if defined(_MSC_VER) && defined(__x86_64__)
 unsigned __int64 _umul128(unsigned __int64,unsigned __int64,unsigned __int64*);
 #endif
diff --git a/include/winnt.h b/include/winnt.h
index 481ee16df79..c02798f321d 100644
--- a/include/winnt.h
+++ b/include/winnt.h
@@ -7400,6 +7400,18 @@ static FORCEINLINE void YieldProcessor(void)

#ifdef __x86_64__

+#if defined(_MSC_VER) && !defined(__arm64ec__) && (!defined(__clang__) || __has_builtin(__shiftright128))
+#define ShiftRight128 __shiftright128
+DWORD64 __shiftright128(DWORD64,DWORD64,BYTE);
+#pragma intrinsic(__shiftright128)
+#elif !defined(__i386__)
+static FORCEINLINE DWORD64 ShiftRight128( DWORD64 lo, DWORD64 hi, BYTE shift )
+{
+    return ((unsigned __int128)hi << 64 | lo) >> shift;
+}
+#define __shiftright128 ShiftRight128
+#endif
+
 #if defined(_MSC_VER) && !defined(__arm64ec__) && (!defined(__clang__) || __has_builtin(_umul128))
 #define UnsignedMultiply128 _umul128
 DWORD64 _umul128(DWORD64,DWORD64,DWORD64*);