Files
system76-edk2/MdePkg/Library/BaseCpuLib/X64/InitializeFpu.nasm
Yu Pu b294633c68 MdePkg: Move API and implementation from UefiCpuLib to CpuLib
There are two libraries: MdePkg/CpuLib and UefiCpuPkg/UefiCpuLib. This
patch merges UefiCpuPkg/UefiCpuLib to MdePkg/CpuLib.

Change-Id: Ic26f4c2614ed6bd9840f817d50e47ac1de4bd013
Cc: Michael D Kinney <michael.d.kinney@intel.com>
Cc: Liming Gao <gaoliming@byosoft.com.cn>
Cc: Zhiguang Liu <zhiguang.liu@intel.com>
Cc: Eric Dong <eric.dong@intel.com>
Cc: Ray Ni <ray.ni@intel.com>
Cc: Rahul Kumar <rahul1.kumar@intel.com>
Signed-off-by: Yu Pu <yu.pu@intel.com>
Reviewed-by: Liming Gao <gaoliming@byosoft.com.cn>
Signed-off-by: Zhiguang Liu <zhiguang.liu@intel.com>
2023-03-10 08:23:56 +00:00

52 lines
1.3 KiB
NASM

;------------------------------------------------------------------------------
;*
;* Copyright (c) 2009 - 2017, Intel Corporation. All rights reserved.<BR>
;* SPDX-License-Identifier: BSD-2-Clause-Patent
;*
;*
;------------------------------------------------------------------------------
SECTION .rodata
;
; Float control word initial value:
; all exceptions masked, double-extended-precision, round-to-nearest
;
mFpuControlWord: DW 0x37F
;
; Multimedia-extensions control word:
; all exceptions masked, round-to-nearest, flush to zero for masked underflow
;
mMmxControlWord: DD 0x1F80
DEFAULT REL
SECTION .text
;
; 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).
;
global ASM_PFX(InitializeFloatingPointUnits)
ASM_PFX(InitializeFloatingPointUnits):
;
; Initialize floating point units
;
finit
fldcw [mFpuControlWord]
;
; Set OSFXSR bit 9 in CR4
;
mov rax, cr4
or rax, BIT9
mov cr4, rax
ldmxcsr [mMmxControlWord]
ret