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#------------------------------------------------------------------------------
#
# Copyright (c) 2014, 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.
#
# Abstract:
#
#------------------------------------------------------------------------------
#
# Float control word initial value:
# all exceptions masked, double-precision, round-to-nearest
#
ASM_PFX(mFpuControlWord): .word 0x027F
#
# Multimedia-extensions control word:
# all exceptions masked, round-to-nearest, flush to zero for masked underflow
#
ASM_PFX(mMmxControlWord): .long 0x01F80
#
# 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).
#
ASM_GLOBAL ASM_PFX(InitializeFloatingPointUnits)
ASM_PFX(InitializeFloatingPointUnits):
pushl %ebx
#
# Initialize floating point units
#
finit
fldcw ASM_PFX(mFpuControlWord)
#
# Use CpuId instructuion (CPUID.01H:EDX.SSE[bit 25] = 1) to test
# whether the processor supports SSE instruction.
#
movl $1, %eax
cpuid
btl $25, %edx
jnc Done
#
# Set OSFXSR bit 9 in CR4
#
movl %cr4, %eax
or BIT9, %eax
movl %eax, %cr4
#
# The processor should support SSE instruction and we can use
# ldmxcsr instruction
#
ldmxcsr ASM_PFX(mMmxControlWord)
Done:
popl %ebx
ret
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