1 files changed, 57 insertions, 0 deletions
diff --git a/CryptoPkg/Library/IntrinsicLib/Ia32/MathRShiftU64.c b/CryptoPkg/Library/IntrinsicLib/Ia32/MathRShiftU64.c
new file mode 100644
index 0000000000..86b10040dd
--- /dev/null
+++ b/CryptoPkg/Library/IntrinsicLib/Ia32/MathRShiftU64.c
@@ -0,0 +1,57 @@
+/** @file
+  64-bit Math Worker Function.
+  The 32-bit versions of C compiler generate calls to library routines
+  to handle 64-bit math. These functions use non-standard calling conventions.
+
+Copyright (c) 2014, Intel Corporation. All rights reserved.<BR>
+This program and the accompanying materials
+are licensed and made available under the terms and conditions of the BSD License
+which accompanies this distribution.  The full text of the license may be found at
+http://opensource.org/licenses/bsd-license.php
+
+THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
+WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
+
+**/
+
+
+/*
+ * Shifts a 64-bit unsigned value right by a certain number of bits.
+ */
+__declspec(naked) void __cdecl _aullshr (void)
+{
+  _asm {
+    ;
+    ; Checking: Only handle 64bit shifting or more
+    ;
+    cmp     cl, 64
+    jae     _Exit
+
+    ;
+    ; Handle shifting between 0 and 31 bits
+    ;
+    cmp     cl, 32
+    jae     More32
+    shrd    eax, edx, cl
+    shr     edx, cl
+    ret
+
+    ;
+    ; Handle shifting of 32-63 bits
+    ;
+More32:
+    mov     eax, edx
+    xor     edx, edx
+    and     cl, 31
+    shr     eax, cl
+    ret
+
+    ;
+    ; Invalid number (less then 32bits), return 0
+    ;
+_Exit:
+    xor     eax, eax
+    xor     edx, edx
+    ret
+  }
+}