Introduce UefiCpuLib library class in UefiCpuPkg and add one instance of BaseUefiCpuLib. The major purpose of this library class / instance is to provide some routines that are generic for IA32 family CPU
git-svn-id: https://edk2.svn.sourceforge.net/svnroot/edk2/trunk/edk2@9480 6f19259b-4bc3-4df7-8a09-765794883524
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54
UefiCpuPkg/Library/BaseUefiCpuLib/X64/InitializeFpu.S
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54
UefiCpuPkg/Library/BaseUefiCpuLib/X64/InitializeFpu.S
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#------------------------------------------------------------------------------
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#*
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#* Copyright 2009, Intel Corporation
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#* All rights reserved. This program and the accompanying materials
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#* are licensed and made available under the terms and conditions of the BSD License
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#* which accompanies this 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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#*
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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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#------------------------------------------------------------------------------
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#
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# Float control word initial value:
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# all exceptions masked, double-precision, round-to-nearest
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#
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ASM_PFX(mFpuControlWord): .word 0x027F
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#
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# Multimedia-extensions control word:
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# all exceptions masked, round-to-nearest, flush to zero for masked underflow
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#
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ASM_PFX(mMmxControlWord): .long 0x01F80
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#
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# Initializes floating point units for requirement of UEFI specification.
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#
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# This function initializes floating-point control word to 0x027F (all exceptions
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# masked,double-precision, round-to-nearest) and multimedia-extensions control word
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# (if supported) to 0x1F80 (all exceptions masked, round-to-nearest, flush to zero
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# for masked underflow).
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#
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ASM_GLOBAL ASM_PFX(InitializeFloatingPointUnits)
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ASM_PFX(InitializeFloatingPointUnits):
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#
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# Initialize floating point units
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#
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finit
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fldcw ASM_PFX(mFpuControlWord)
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#
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# Set OSFXSR bit 9 in CR4
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#
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movq %cr4, %rax
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or $200, %rax
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movq %rax, %cr4
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ldmxcsr ASM_PFX(mMmxControlWord)
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ret
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