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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
59 lines
1.5 KiB
C
59 lines
1.5 KiB
C
/** @file
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64-bit Math Worker Function.
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The 32-bit versions of C compiler generate calls to library routines
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to handle 64-bit math. These functions use non-standard calling conventions.
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Copyright (c) 2009 - 2011, Intel Corporation. All rights reserved.<BR>
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This program and the accompanying materials are licensed and made available
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under the terms and conditions of the BSD License which accompanies this
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distribution. The full text of the license may be found at
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http://opensource.org/licenses/bsd-license.php.
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THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
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WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
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**/
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/*
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* Shifts a 64-bit signed value right by a particular number of bits.
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*/
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__declspec(naked) void __cdecl _allshr (void)
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{
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_asm {
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;
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; Handle shifts of 64 bits or more (if shifting 64 bits or more, the result
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; depends only on the high order bit of edx).
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;
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cmp cl,64
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jae short SIGNRETURN
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;
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; Handle shifts of between 0 and 31 bits
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;
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cmp cl, 32
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jae short MORE32
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shrd eax,edx,cl
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sar edx,cl
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ret
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;
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; Handle shifts of between 32 and 63 bits
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;
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MORE32:
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mov eax,edx
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sar edx,31
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and cl,31
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sar eax,cl
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ret
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;
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; Return double precision 0 or -1, depending on the sign of edx
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;
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SIGNRETURN:
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sar edx,31
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mov eax,edx
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ret
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}
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}
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