UefiCpuPkg/CpuDxe/X64/CpuAsm.S

   1 #      TITLE   CpuAsm.S:
   2
   3 #------------------------------------------------------------------------------
   4 #*
   5 #*   Copyright (c) 2008 - 2013, Intel Corporation. All rights reserved.<BR>
   6 #*   This program and the accompanying materials
   7 #*   are licensed and made available under the terms and conditions of the BSD License
   8 #*   which accompanies this distribution.  The full text of the license may be found at
   9 #*   http://opensource.org/licenses/bsd-license.php
  10 #*
  11 #*   THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
  12 #*   WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
  13 #*
  14 #*    CpuAsm.S
  15 #*
  16 #*   Abstract:
  17 #*
  18 #------------------------------------------------------------------------------
  19
  20
  21 #text  SEGMENT
  22
  23
  24 #------------------------------------------------------------------------------
  25 # VOID
  26 # SetCodeSelector (
  27 #   UINT16 Selector
  28 #   );
  29 #------------------------------------------------------------------------------
  30 ASM_GLOBAL ASM_PFX(SetCodeSelector)
  31 ASM_PFX(SetCodeSelector):
  32     subq    $0x10, %rsp
  33     leaq    L_setCodeSelectorLongJump(%rip), %rax
  34     movq    %rax, (%rsp)
  35     movw    %cx, 4(%rsp)
  36     .byte   0xFF, 0x2C, 0x24     # jmp (%rsp) note:fword jmp
  37 L_setCodeSelectorLongJump:
  38     addq    $0x10, %rsp
  39     ret
  40
  41 #------------------------------------------------------------------------------
  42 # VOID
  43 # SetDataSelectors (
  44 #   UINT16 Selector
  45 #   );
  46 #------------------------------------------------------------------------------
  47 ASM_GLOBAL ASM_PFX(SetDataSelectors)
  48 ASM_PFX(SetDataSelectors):
  49     movw    %cx, %ss
  50     movw    %cx, %ds
  51     movw    %cx, %es
  52     movw    %cx, %fs
  53     movw    %cx, %gs
  54     ret
  55
  56 #text  ENDS
  57
  58 #END
  59
  60