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| author | Guo Mang <mang.guo@intel.com> | 2016-12-22 17:11:19 +0800 |
|---|---|---|
| committer | Guo Mang <mang.guo@intel.com> | 2016-12-26 19:14:50 +0800 |
| commit | 2cc68ed95f4e6a5b6256a6cc1e9f6a585a7d2ba7 (patch) | |
| tree | e6f0cc497ee0f06782388ab114fd2f3d37bddcc5 /Core/UefiCpuPkg/Library/BaseUefiCpuLib/X64/InitializeFpu.asm | |
| parent | a6747ab91782ba4309b5f12301c8b43b1b4702dd (diff) | |
| download | edk2-platforms-2cc68ed95f4e6a5b6256a6cc1e9f6a585a7d2ba7.tar.xz | |
UefiCpuPkg: Move to new location
Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Guo Mang <mang.guo@intel.com>
Diffstat (limited to 'Core/UefiCpuPkg/Library/BaseUefiCpuLib/X64/InitializeFpu.asm')
| -rw-r--r-- | Core/UefiCpuPkg/Library/BaseUefiCpuLib/X64/InitializeFpu.asm | 62 |
1 files changed, 62 insertions, 0 deletions
diff --git a/Core/UefiCpuPkg/Library/BaseUefiCpuLib/X64/InitializeFpu.asm b/Core/UefiCpuPkg/Library/BaseUefiCpuLib/X64/InitializeFpu.asm new file mode 100644 index 0000000000..331af15cc6 --- /dev/null +++ b/Core/UefiCpuPkg/Library/BaseUefiCpuLib/X64/InitializeFpu.asm @@ -0,0 +1,62 @@ +;------------------------------------------------------------------------------
+;*
+;* Copyright (c) 2009 - 2012, 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.
+;*
+;*
+;------------------------------------------------------------------------------
+
+
+.const
+;
+; Float control word initial value:
+; all exceptions masked, double-extended-precision, round-to-nearest
+;
+mFpuControlWord DW 037Fh
+;
+; Multimedia-extensions control word:
+; all exceptions masked, round-to-nearest, flush to zero for masked underflow
+;
+mMmxControlWord DD 01F80h
+
+.code
+
+
+;
+; Initializes floating point units for requirement of UEFI specification.
+;
+; This function initializes floating-point control word to 0x027F (all exceptions
+; masked,double-precision, round-to-nearest) and multimedia-extensions control word
+; (if supported) to 0x1F80 (all exceptions masked, round-to-nearest, flush to zero
+; for masked underflow).
+;
+InitializeFloatingPointUnits PROC PUBLIC
+
+ ;
+ ; Initialize floating point units
+ ;
+ ; The following opcodes stand for instruction 'finit'
+ ; to be supported by some 64-bit assemblers
+ ;
+ DB 9Bh, 0DBh, 0E3h
+ fldcw mFpuControlWord
+
+ ;
+ ; Set OSFXSR bit 9 in CR4
+ ;
+ mov rax, cr4
+ or rax, BIT9
+ mov cr4, rax
+
+ ldmxcsr mMmxControlWord
+
+ ret
+InitializeFloatingPointUnits ENDP
+
+END
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