diff options
Diffstat (limited to 'EdkCompatibilityPkg/Foundation/Library/EfiCommonLib/Ia32/MultU64x32.c')
-rw-r--r-- | EdkCompatibilityPkg/Foundation/Library/EfiCommonLib/Ia32/MultU64x32.c | 64 |
1 files changed, 64 insertions, 0 deletions
diff --git a/EdkCompatibilityPkg/Foundation/Library/EfiCommonLib/Ia32/MultU64x32.c b/EdkCompatibilityPkg/Foundation/Library/EfiCommonLib/Ia32/MultU64x32.c new file mode 100644 index 0000000000..a102b0e684 --- /dev/null +++ b/EdkCompatibilityPkg/Foundation/Library/EfiCommonLib/Ia32/MultU64x32.c @@ -0,0 +1,64 @@ +/*++
+
+Copyright (c) 2006, Intel Corporation
+All rights reserved. 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.
+
+Module Name:
+
+ MultU64x32.c
+
+Abstract:
+
+ 64-bit Multiplication function for IA-32
+
+--*/
+
+#include "Tiano.h"
+
+UINT64
+MultU64x32 (
+ IN UINT64 Multiplicand,
+ IN UINTN Multiplier
+ )
+/*++
+
+Routine Description:
+
+ This routine allows a 64 bit value to be multiplied with a 32 bit
+ value returns 64bit result.
+ No checking if the result is greater than 64bits
+
+Arguments:
+
+ Multiplicand - multiplicand
+ Multiplier - multiplier
+
+Returns:
+
+ Multiplicand * Multiplier
+
+--*/
+{
+ __asm {
+ mov eax, dword ptr Multiplicand[0]
+ mul Multiplier
+ push eax
+ push edx
+ mov eax, dword ptr Multiplicand[4]
+ mul Multiplier
+ ;
+ ; The value in edx stored by second multiplication overflows
+ ; the output and should be discarded. So here we overwrite it
+ ; with the edx value of first multiplication.
+ ;
+ pop edx
+ add edx, eax
+ pop eax
+ }
+}
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