UefiCpuPkg/ResetVector/Vtf0/Ia16/ResetVectorVtf0.asm

   1 ;------------------------------------------------------------------------------
   2 ; @file
   3 ; First code executed by processor after resetting.
   4 ;
   5 ; Copyright (c) 2008 - 2014, Intel Corporation. All rights reserved.<BR>
   6 ; SPDX-License-Identifier: BSD-2-Clause-Patent
   7 ;
   8 ;------------------------------------------------------------------------------
   9
  10 BITS    16
  11
  12 ALIGN   16
  13
  14 ;
  15 ; Pad the image size to 4k when page tables are in VTF0
  16 ;
  17 ; If the VTF0 image has page tables built in, then we need to make
  18 ; sure the end of VTF0 is 4k above where the page tables end.
  19 ;
  20 ; This is required so the page tables will be 4k aligned when VTF0 is
  21 ; located just below 0x100000000 (4GB) in the firmware device.
  22 ;
  23 %ifdef ALIGN_TOP_TO_4K_FOR_PAGING
  24     TIMES (0x1000 - ($ - EndOfPageTables)) DB 0
  25 ;
  26 ; Pad the VTF0 Reset code for Bsp & Ap to 4k aligned block.
  27 ; Some implementations may need to keep the initial Reset code
  28 ; to be separated out from rest of the code.
  29 ; This padding will make sure lower 4K region below 4 GB may
  30 ; only contains few jmp instructions and data.
  31 ;
  32     TIMES (0x1000 - 0x20) DB 0
  33 %endif
  34
  35 applicationProcessorEntryPoint:
  36 ;
  37 ; Application Processors entry point
  38 ;
  39 ; GenFv generates code aligned on a 4k boundary which will jump to this
  40 ; location.  (0xffffffe0)  This allows the Local APIC Startup IPI to be
  41 ; used to wake up the application processors.
  42 ;
  43     jmp     EarlyApInitReal16
  44
  45 ALIGN   8
  46
  47     DD      0
  48
  49 ;
  50 ; The VTF signature
  51 ;
  52 ; VTF-0 means that the VTF (Volume Top File) code does not require
  53 ; any fixups.
  54 ;
  55 vtfSignature:
  56     DB      'V', 'T', 'F', 0
  57
  58 ALIGN   16
  59
  60 resetVector:
  61 ;
  62 ; Reset Vector
  63 ;
  64 ; This is where the processor will begin execution
  65 ;
  66     nop
  67     nop
  68     jmp     EarlyBspInitReal16
  69
  70 ALIGN   16
  71
  72 fourGigabytes:
  73