MdePkg/Library/BaseLib/ia32/Thunk16.s

   1 #------------------------------------------------------------------------------
   2 #
   3 # Copyright (c) 2006, Intel Corporation
   4 # All rights reserved. This program and the accompanying materials
   5 # are licensed and made available under the terms and conditions of the BSD License
   6 # which accompanies this distribution.  The full text of the license may be found at
   7 # http://opensource.org/licenses/bsd-license.php
   8 #
   9 # THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
  10 # WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
  11 #
  12 # Module Name:
  13 #
  14 #   Thunk.asm
  15 #
  16 # Abstract:
  17 #
  18 #   Real mode thunk
  19 #
  20 #------------------------------------------------------------------------------
  21
  22
  23
  24 MISMATCH: "EXTERNDEF   C   mCode16Size:DWORD"
  25
  26 MISMATCH: "CONST   SEGMENT FLAT    "DATA"  READONLY"
  27
  28 MISMATCH: "mCode16Size     DD      _TEXT16SIZE"
  29
  30 MISMATCH: "CONSTS"
  31
  32 MISMATCH: "_DATA   SEGMENT FLAT    "DATA""
  33
  34 MISMATCH: "NullSegSel      DQ      0"
  35 MISMATCH: "_16BitCsSel     LABEL   QWORD"
  36                 .word -1
  37                 .word 0
  38                 .byte 0
  39                 .byte 0x9b
  40                 .byte 0x8f              # 16-bit segment
  41                 .byte 0
  42
  43 MISMATCH: "_16Gdtr         LABEL   FWORD"
  44 MISMATCH: "                DW      $ - offset NullSegSel - 1"
  45 MISMATCH: "                DD      offset NullSegSel"
  46
  47 MISMATCH: "_DATAS"
  48
  49 MISMATCH: "_TEXT   SEGMENT FLAT    "CODE"  PARA"
  50
  51 MISMATCH: "IA32_REGS   STRUC   4t"
  52 MISMATCH: "_EDI        DD      ?"
  53 MISMATCH: "_ESI        DD      ?"
  54 MISMATCH: "_EBP        DD      ?"
  55 MISMATCH: "_ESP        DD      ?"
  56 MISMATCH: "_EBX        DD      ?"
  57 MISMATCH: "_EDX        DD      ?"
  58 MISMATCH: "_ECX        DD      ?"
  59 MISMATCH: "_EAX        DD      ?"
  60 MISMATCH: "_DS         DW      ?"
  61 MISMATCH: "_ES         DW      ?"
  62 MISMATCH: "_FS         DW      ?"
  63 MISMATCH: "_GS         DW      ?"
  64 MISMATCH: "_EFLAGS     DD      ?"
  65 MISMATCH: "_EIP        DD      ?"
  66 MISMATCH: "_CS         DW      ?"
  67 MISMATCH: "_SS         DW      ?"
  68 MISMATCH: "IA32_REGSS"
  69
  70 MISMATCH: "_STK16      STRUC   1t"
  71 MISMATCH: "RetEip      DD      ?"
  72 MISMATCH: "RetCs       DW      ?"
  73 MISMATCH: "ThunkFlags  DW      ?"
  74 MISMATCH: "SavedEsp    DD      ?"
  75 MISMATCH: "SavedSs     DW      ?"
  76 MISMATCH: "SavedGdtr   FWORD   ?"
  77 MISMATCH: "SavedCr0    DD      ?"
  78 MISMATCH: "SavedCr4    DD      ?"
  79 MISMATCH: "_STK16S"
  80
  81 .global _InternalAsmThunk16
  82 MISMATCH: "_InternalAsmThunk16:    USES    ebp ebx esi edi ds  es  fs  gs"
  83 MISMATCH: "    ASSUME  esi:PTR IA32_REGS"
  84     movl    36(%esp),%esi
  85 MISMATCH: "    movzx   edx, [esi]._SS"
  86     movl    $[esi]._ESP, %edi
  87 MISMATCH: "    add     edi, - sizeof (_STK16) - sizeof (IA32_REGS)"
  88     pushl   %edi                        # save stack offset
  89     imull   $16,%edx,%eax               # eax <- edx*16
  90     addl    %eax,%edi                   # edi <- linear address of 16-bit stack
  91 MISMATCH: "    push    sizeof (IA32_REGS) / 4"
  92     popl    %ecx
  93     rep
  94     movsl                               # copy context to 16-bit stack
  95     popl    %ebx                        # ebx <- 16-bit stack offset
  96 MISMATCH: "    mov     eax, offset @F              "
  97     stosl
  98     movl    %cs,%eax                    # return segment
  99     stosw
 100     movl    40(%esp),%eax               # THUNK flags
 101     stosw
 102     movl    %esp,%eax
 103     stosl                               # save esp
 104     movl    %ss,%eax                    # save ss
 105     stosw
 106 MISMATCH: "    sgdt    fword ptr [edi]             "
 107 MISMATCH: "    sidt    fword ptr [esp + 36]        "
 108     movl    %cr0, %esi
 109     movl    %esi,6(%edi)                # save CR0
 110 MISMATCH: "    and     esi, NOT 80000001h          "
 111     movl    %cr4, %eax
 112     movl    %eax,10(%edi)               # save CR4
 113 MISMATCH: "    and     al, NOT 30h                 "
 114     movl    %edx,%edi                   # edi <- 16-bit stack segment
 115     movl    44(%esp),%edx
 116     shll    $16,%edx
 117     pushl   %edx
 118 MISMATCH: "    lgdt    _16Gdtr                     "
 119     .byte 0xea
 120 MISMATCH: "    DD      offset @16Bit"
 121     .word 8                             # jmp far 8:@16Bit
 122 @16Bit:
 123     movl    %esi, %cr0                  # disable protected mode
 124     movl    %eax, %cr4                  # disable PAE & PSE
 125     lret
 126 @@:
 127     movl    %ss,%eax
 128     shll    $4,%eax
 129     addl    %esp,%eax                   # eax <- address of 16-bit stack
 130 MISMATCH: "    lss     esp, fword ptr (_STK16 ptr [esp + sizeof (IA32_REGS)]).SavedEsp"
 131 MISMATCH: "    lidt    fword ptr [esp + 36]        "
 132     ret
 133
 134
 135 MISMATCH: "_TEXTS"
 136
 137 MISMATCH: "_TEXT16 SEGMENT USE16   "CODE"  PARA"
 138
 139 .global _Code16Addr
 140 MISMATCH: "_Code16Addr:    C"
 141
 142
 143 .global RealMode
 144 RealMode:
 145 MISMATCH: "    ASSUME  bp:PTR _STK16"
 146     movw    %di,%ss                     # set up stack
 147     movl    %ebx,%esp
 148 MISMATCH: "    lidt    fword ptr cs:[_16Idtr - _Code16Addr]"
 149     popal
 150     popl    %ds
 151     popl    %es
 152     popl    %fs
 153     popl    %gs
 154     addw    $4,%sp                      # skip EFlags
 155 MISMATCH: "    test    (_STK16 ptr [esp + 8]).ThunkFlags, 1"
 156     jz      @F
 157     pushf
 158 @@:
 159     pushw   %cs
 160 MISMATCH: "    push    @FarCallRet - _Code16Addr"
 161     jz      @F
 162 MISMATCH: "    jmp     fword ptr [esp + 6]"
 163 @@:
 164 MISMATCH: "    jmp     fword ptr [esp + 4]"
 165 @FarCallRet:
 166     pushfl
 167     pushw   %gs
 168     pushw   %fs
 169     pushw   %es
 170     pushw   %ds
 171     pushal
 172     cli
 173 MISMATCH: "    lea     bp, [esp + sizeof (IA32_REGS)]"
 174     .byte 0x66
 175 MISMATCH: "    lgdt    [bp].SavedGdtr"
 176     movl    $[bp].SavedCr4, %eax
 177     movl    %eax, %cr4
 178     movl    $[bp].SavedCr0, %eax
 179     movl    %eax, %cr0                  # restore CR0
 180 MISMATCH: "    jmp     fword ptr [bp].RetEip"
 181
 182
 183 MISMATCH: "_16Idtr     FWORD   (1 SHL 10) - 1"
 184
 185 _TEXT16:
 186
 187 MISMATCH: "_TEXT16SIZE = _TEXT16- _Code16Addr"
 188
 189 MISMATCH: "_TEXT16S"
 190
 191