UefiCpuPkg/CpuMpPei/X64/MpFuncs.asm

   1 ;------------------------------------------------------------------------------ ;
   2 ; Copyright (c) 2015, Intel Corporation. All rights reserved.<BR>
   3 ; This program and the accompanying materials
   4 ; are licensed and made available under the terms and conditions of the BSD License
   5 ; which accompanies this distribution.  The full text of the license may be found at
   6 ; http://opensource.org/licenses/bsd-license.php.
   7 ;
   8 ; THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
   9 ; WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
  10 ;
  11 ; Module Name:
  12 ;
  13 ;   MpFuncs32.asm
  14 ;
  15 ; Abstract:
  16 ;
  17 ;   This is the assembly code for MP support
  18 ;
  19 ;-------------------------------------------------------------------------------
  20
  21 include  MpEqu.inc
  22 .code
  23
  24
  25 AsmInitializeGdt   PROC
  26     push       rbp
  27     mov        rbp, rsp
  28
  29     lgdt       fword PTR [rcx]  ; update the GDTR
  30
  31     sub        rsp, 0x10
  32     lea        rax, SetCodeSelectorFarJump
  33     mov        [rsp], rax
  34     mov        rdx, LONG_MODE_CS
  35     mov        [rsp + 4], dx    ; get new CS
  36     jmp        fword ptr [rsp]
  37 SetCodeSelectorFarJump:
  38     add        rsp, 0x10
  39
  40     mov        rax, LONG_MODE_DS          ; get new DS
  41     mov        ds, ax
  42     mov        es, ax
  43     mov        fs, ax
  44     mov        gs, ax
  45     mov        ss, ax
  46
  47     pop        rbp
  48     ret
  49 AsmInitializeGdt  ENDP
  50
  51 END