CryptoPkg Updates to support RFC3161 timestamp signature verification.

[mirror_edk2.git] / CryptoPkg / Library / IntrinsicLib / Ia32 / MathRShiftU64.c

diff --git a/CryptoPkg/Library/IntrinsicLib/Ia32/MathRShiftU64.c b/CryptoPkg/Library/IntrinsicLib/Ia32/MathRShiftU64.c
new file mode 100644 (file)
index 0000000..86b1004
--- /dev/null
+++ b/CryptoPkg/Library/IntrinsicLib/Ia32/MathRShiftU64.c
@@ -0,0 +1,57 @@
+/** @file\r
+  64-bit Math Worker Function.\r
+  The 32-bit versions of C compiler generate calls to library routines\r
+  to handle 64-bit math. These functions use non-standard calling conventions.\r
+\r
+Copyright (c) 2014, Intel Corporation. All rights reserved.<BR>\r
+This program and the accompanying materials\r
+are licensed and made available under the terms and conditions of the BSD License\r
+which accompanies this distribution.  The full text of the license may be found at\r
+http://opensource.org/licenses/bsd-license.php\r
+\r
+THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,\r
+WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.\r
+\r
+**/\r
+\r
+\r
+/*\r
+ * Shifts a 64-bit unsigned value right by a certain number of bits.\r
+ */\r
+__declspec(naked) void __cdecl _aullshr (void)\r
+{\r
+  _asm {\r
+    ;\r
+    ; Checking: Only handle 64bit shifting or more\r
+    ;\r
+    cmp     cl, 64\r
+    jae     _Exit\r
+\r
+    ;\r
+    ; Handle shifting between 0 and 31 bits\r
+    ;\r
+    cmp     cl, 32\r
+    jae     More32\r
+    shrd    eax, edx, cl\r
+    shr     edx, cl\r
+    ret\r
+\r
+    ;\r
+    ; Handle shifting of 32-63 bits\r
+    ;\r
+More32:\r
+    mov     eax, edx\r
+    xor     edx, edx\r
+    and     cl, 31\r
+    shr     eax, cl\r
+    ret\r
+\r
+    ;\r
+    ; Invalid number (less then 32bits), return 0\r
+    ;\r
+_Exit:\r
+    xor     eax, eax\r
+    xor     edx, edx\r
+    ret\r
+  }\r
+}\r