UefiCpuPkg/ResetVector/Vtf0/Main.asm

   1 ;------------------------------------------------------------------------------
   2 ; @file
   3 ; Main routine of the pre-SEC code up through the jump into SEC
   4 ;
   5 ; Copyright (c) 2008 - 2009, 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 ;------------------------------------------------------------------------------
  15
  16
  17 BITS    16
  18
  19 ;
  20 ; Modified:  EBX, ECX, EDX, EBP
  21 ;
  22 ; @param[in,out]  RAX/EAX  Initial value of the EAX register
  23 ;                          (BIST: Built-in Self Test)
  24 ; @param[in,out]  DI       'BP': boot-strap processor, or
  25 ;                          'AP': application processor
  26 ; @param[out]     RBP/EBP  Address of Boot Firmware Volume (BFV)
  27 ;
  28 ; @return         None  This routine jumps to SEC and does not return
  29 ;
  30 Main16:
  31     OneTimeCall EarlyInit16
  32
  33     ;
  34     ; Transition the processor from 16-bit real mode to 32-bit flat mode
  35     ;
  36     OneTimeCall TransitionFromReal16To32BitFlat
  37
  38 BITS    32
  39
  40     ;
  41     ; Search for the Boot Firmware Volume (BFV)
  42     ;
  43     OneTimeCall Flat32SearchForBfvBase
  44
  45     ;
  46     ; EBP - Start of BFV
  47     ;
  48
  49     ;
  50     ; Search for the SEC entry point
  51     ;
  52     OneTimeCall Flat32SearchForSecEntryPoint
  53
  54     ;
  55     ; ESI - SEC Core entry point
  56     ; EBP - Start of BFV
  57     ;
  58
  59 %ifdef ARCH_IA32
  60
  61     ;
  62     ; Restore initial EAX value into the EAX register
  63     ;
  64     mov     eax, esp
  65
  66     ;
  67     ; Jump to the 32-bit SEC entry point
  68     ;
  69     jmp     esi
  70
  71 %else
  72
  73     ;
  74     ; Transition the processor from 32-bit flat mode to 64-bit flat mode
  75     ;
  76     OneTimeCall Transition32FlatTo64Flat
  77
  78 BITS    64
  79
  80     ;
  81     ; Some values were calculated in 32-bit mode.  Make sure the upper
  82     ; 32-bits of 64-bit registers are zero for these values.
  83     ;
  84     mov     rax, 0x00000000ffffffff
  85     and     rsi, rax
  86     and     rbp, rax
  87     and     rsp, rax
  88
  89     ;
  90     ; RSI - SEC Core entry point
  91     ; RBP - Start of BFV
  92     ;
  93
  94     ;
  95     ; Restore initial EAX value into the RAX register
  96     ;
  97     mov     rax, rsp
  98
  99     ;
 100     ; Jump to the 64-bit SEC entry point
 101     ;
 102     jmp     rsi
 103
 104 %endif
 105
 106