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| author | Daryl McDaniel <daryl.mcdaniel@intel.com> | 2014-08-20 20:38:43 +0000 |
|---|---|---|
| committer | darylm503 <darylm503@6f19259b-4bc3-4df7-8a09-765794883524> | 2014-08-20 20:38:43 +0000 |
| commit | dfa8858555070f08ba9df2c2dde837f8c7620b51 (patch) | |
| tree | 9ffb496a8c1ca5f986caa14533c7dda7fe8e4b9f /StdLib/LibC/CRT/Ia32 | |
| parent | cb6032832355f5abe3967862603625f11b710418 (diff) | |
| download | edk2-platforms-dfa8858555070f08ba9df2c2dde837f8c7620b51.tar.xz | |
StdLib: Add a runtime helper function for VC++ 64-bit right shift on Ia32 target architectures.
Add new file StdLib/LibC/CRT/Ia32/llshr.c
Add references to the new file to StdLib/LibC/LibC.inf
Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Daryl McDaniel <daryl.mcdaniel@intel.com>
Reviewed-by: Erik Bjorge <erik.c.bjorge@intel.com>
git-svn-id: https://svn.code.sf.net/p/edk2/code/trunk/edk2@15855 6f19259b-4bc3-4df7-8a09-765794883524
Diffstat (limited to 'StdLib/LibC/CRT/Ia32')
| -rw-r--r-- | StdLib/LibC/CRT/Ia32/llshr.c | 58 |
1 files changed, 58 insertions, 0 deletions
diff --git a/StdLib/LibC/CRT/Ia32/llshr.c b/StdLib/LibC/CRT/Ia32/llshr.c new file mode 100644 index 0000000000..38770ac43f --- /dev/null +++ b/StdLib/LibC/CRT/Ia32/llshr.c @@ -0,0 +1,58 @@ +/** @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) 2009 - 2011, 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 signed value right by a particular number of bits.
+ */
+__declspec(naked) void __cdecl _allshr (void)
+{
+ _asm {
+ ;
+ ; Handle shifts of 64 bits or more (if shifting 64 bits or more, the result
+ ; depends only on the high order bit of edx).
+ ;
+ cmp cl,64
+ jae short SIGNRETURN
+
+ ;
+ ; Handle shifts of between 0 and 31 bits
+ ;
+ cmp cl, 32
+ jae short MORE32
+ shrd eax,edx,cl
+ sar edx,cl
+ ret
+
+ ;
+ ; Handle shifts of between 32 and 63 bits
+ ;
+MORE32:
+ mov eax,edx
+ sar edx,31
+ and cl,31
+ sar eax,cl
+ ret
+
+ ;
+ ; Return double precision 0 or -1, depending on the sign of edx
+ ;
+SIGNRETURN:
+ sar edx,31
+ mov eax,edx
+ ret
+ }
+}
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