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;; @file
; This file provides assembly 64-bit atomic reads/writes required for memory initialization.
;
; Copyright (c) 2017, 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 that 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.
;
;;
SECTION .TEXT
;-----------------------------------------------------------------------------
;
; Section: SaMmioRead64
;
; Description: Read 64 bits from the Memory Mapped I/O space.
; Use MMX instruction for atomic access, because some MC registers have side effect.
;
; @param[in] Address - Memory mapped I/O address.
;
;-----------------------------------------------------------------------------
;UINT64
;SaMmioRead64 (
; IN UINTN Address
; )
global ASM_PFX(SaMmioRead64)
ASM_PFX(SaMmioRead64):
sub esp, 16
movq [esp], mm0 ;Save mm0 on stack
mov edx, [esp + 20] ;edx = Address
movq mm0, [edx] ;mm0 = [Address]
movq [esp + 8], mm0 ;Store mm0 on Stack
movq mm0, [esp] ;Restore mm0
emms
mov eax, [esp + 8] ;eax = [Address][31:0]
mov edx, [esp + 12] ;edx = [Address][64:32]
add esp, 16
ret
;-----------------------------------------------------------------------------
;
; Section: SaMmioWrite64
;
; Description: Write 64 bits to the Memory Mapped I/O space.
; Use MMX instruction for atomic access, because some MC registers have side effect.
;
; @param[in] Address - Memory mapped I/O address.
; @param[in] Value - The value to write.
;
;-----------------------------------------------------------------------------
;UINT64
;SaMmioWrite64 (
; IN UINTN Address,
; IN UINT64 Value
; )
global ASM_PFX(SaMmioWrite64)
ASM_PFX(SaMmioWrite64):
sub esp, 8
movq [esp], mm0 ;Save mm0 on Stack
mov edx, [esp + 12] ;edx = Address
movq mm0, [esp + 16] ;mm0 = Value
movq [edx], mm0 ;[Address] = Value
movq mm0, [esp] ;Restore mm0
emms
mov eax, [esp + 16] ;eax = Value[31:0]
mov edx, [esp + 20] ;edx = Value[64:32]
add esp, 8
ret
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