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BaseUefiCpuLib: Preserve EBX register in InitializeFloatingPointUnits

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The EBX register should be preserved for the IA32 C calling convention.
The use of the CPUID instruction was modifying the EBX register, so
we push and pop EBX.

git-svn-id: https://edk2.svn.sourceforge.net/svnroot/edk2/trunk/edk2@9573 6f19259b-4bc3-4df7-8a09-765794883524
This commit is contained in:
jljusten 2009-12-16 23:29:20 +00:00
parent 0913fadc1a
commit d6d8e8925f
2 changed files with 49 additions and 40 deletions
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81
UefiCpuPkg/Library/BaseUefiCpuLib/Ia32/InitializeFpu.S
View File

@ -1,19 +1,19 @@
#------------------------------------------------------------------------------ #------------------------------------------------------------------------------
#* #*
#* Copyright 2009, Intel Corporation #* Copyright 2009, Intel Corporation
#* All rights reserved. This program and the accompanying materials #* All rights reserved. This program and the accompanying materials
#* are licensed and made available under the terms and conditions of the BSD License #* 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 #* which accompanies this distribution. The full text of the license may be found at
#* http://opensource.org/licenses/bsd-license.php #* http://opensource.org/licenses/bsd-license.php
#* #*
#* THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS, #* THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
#* WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED. #* WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
#* #*
#* #*
#------------------------------------------------------------------------------ #------------------------------------------------------------------------------
# #
# Float control word initial value: # Float control word initial value:
# all exceptions masked, double-precision, round-to-nearest # all exceptions masked, double-precision, round-to-nearest
@ -23,18 +23,21 @@ ASM_PFX(mFpuControlWord): .word 0x027F
# Multimedia-extensions control word: # Multimedia-extensions control word:
# all exceptions masked, round-to-nearest, flush to zero for masked underflow # all exceptions masked, round-to-nearest, flush to zero for masked underflow
# #
ASM_PFX(mMmxControlWord): .long 0x01F80 ASM_PFX(mMmxControlWord): .long 0x01F80
# #
# Initializes floating point units for requirement of UEFI specification. # Initializes floating point units for requirement of UEFI specification.
# #
# This function initializes floating-point control word to 0x027F (all exceptions # This function initializes floating-point control word to 0x027F (all exceptions
# masked,double-precision, round-to-nearest) and multimedia-extensions control word # masked,double-precision, round-to-nearest) and multimedia-extensions control word
# (if supported) to 0x1F80 (all exceptions masked, round-to-nearest, flush to zero # (if supported) to 0x1F80 (all exceptions masked, round-to-nearest, flush to zero
# for masked underflow). # for masked underflow).
# #
ASM_GLOBAL ASM_PFX(InitializeFloatingPointUnits) ASM_GLOBAL ASM_PFX(InitializeFloatingPointUnits)
ASM_PFX(InitializeFloatingPointUnits): ASM_PFX(InitializeFloatingPointUnits):
pushl %ebx
# #
# Initialize floating point units # Initialize floating point units
# #
@ -49,22 +52,24 @@ ASM_PFX(InitializeFloatingPointUnits):
cpuid cpuid
btl $25, %edx btl $25, %edx
jnc Done jnc Done
# #
# Set OSFXSR bit 9 in CR4 # Set OSFXSR bit 9 in CR4
# #
movl %cr4, %eax movl %cr4, %eax
or $200, %eax or $200, %eax
movl %eax, %cr4 movl %eax, %cr4
# #
# The processor should support SSE instruction and we can use # The processor should support SSE instruction and we can use
# ldmxcsr instruction # ldmxcsr instruction
# #
ldmxcsr ASM_PFX(mMmxControlWord) ldmxcsr ASM_PFX(mMmxControlWord)
Done: Done:
ret popl %ebx
#END ret
#END

8
UefiCpuPkg/Library/BaseUefiCpuLib/Ia32/InitializeFpu.asm
View File

@ -30,15 +30,18 @@ mMmxControlWord DD 01F80h
.xmm .xmm
.code .code
; ;
; Initializes floating point units for requirement of UEFI specification. ; Initializes floating point units for requirement of UEFI specification.
; ;
; This function initializes floating-point control word to 0x027F (all exceptions ; This function initializes floating-point control word to 0x027F (all exceptions
; masked,double-precision, round-to-nearest) and multimedia-extensions control word ; masked,double-precision, round-to-nearest) and multimedia-extensions control word
; (if supported) to 0x1F80 (all exceptions masked, round-to-nearest, flush to zero ; (if supported) to 0x1F80 (all exceptions masked, round-to-nearest, flush to zero
; for masked underflow). ; for masked underflow).
; ;
InitializeFloatingPointUnits PROC PUBLIC InitializeFloatingPointUnits PROC PUBLIC
push ebx
; ;
; Initialize floating point units ; Initialize floating point units
; ;
@ -67,6 +70,7 @@ InitializeFloatingPointUnits PROC PUBLIC
; ;
ldmxcsr mMmxControlWord ldmxcsr mMmxControlWord
Done: Done:
pop ebx
ret ret