diff options
Diffstat (limited to 'MdePkg/Library/BaseLib/Ia32/Thunk16.s')
| -rw-r--r-- | MdePkg/Library/BaseLib/Ia32/Thunk16.s | 191 |
1 files changed, 191 insertions, 0 deletions
diff --git a/MdePkg/Library/BaseLib/Ia32/Thunk16.s b/MdePkg/Library/BaseLib/Ia32/Thunk16.s new file mode 100644 index 0000000000..4236996226 --- /dev/null +++ b/MdePkg/Library/BaseLib/Ia32/Thunk16.s @@ -0,0 +1,191 @@ +#------------------------------------------------------------------------------
+#
+# Copyright (c) 2006, Intel Corporation
+# All rights reserved. This program and the accompanying materials
+# are licensed and made available under the terms and conditions of the BSD License
+# which accompanies this distribution. The full text of the license may be found at
+# http://opensource.org/licenses/bsd-license.php
+#
+# THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
+# WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
+#
+# Module Name:
+#
+# Thunk.asm
+#
+# Abstract:
+#
+# Real mode thunk
+#
+#------------------------------------------------------------------------------
+
+
+
+MISMATCH: "EXTERNDEF C mCode16Size:DWORD"
+
+MISMATCH: "CONST SEGMENT FLAT "DATA" READONLY"
+
+MISMATCH: "mCode16Size DD _TEXT16SIZE"
+
+MISMATCH: "CONSTS"
+
+MISMATCH: "_DATA SEGMENT FLAT "DATA""
+
+MISMATCH: "NullSegSel DQ 0"
+MISMATCH: "_16BitCsSel LABEL QWORD"
+ .word -1
+ .word 0
+ .byte 0
+ .byte 0x9b
+ .byte 0x8f # 16-bit segment
+ .byte 0
+
+MISMATCH: "_16Gdtr LABEL FWORD"
+MISMATCH: " DW $ - offset NullSegSel - 1"
+MISMATCH: " DD offset NullSegSel"
+
+MISMATCH: "_DATAS"
+
+MISMATCH: "_TEXT SEGMENT FLAT "CODE" PARA"
+
+MISMATCH: "IA32_REGS STRUC 4t"
+MISMATCH: "_EDI DD ?"
+MISMATCH: "_ESI DD ?"
+MISMATCH: "_EBP DD ?"
+MISMATCH: "_ESP DD ?"
+MISMATCH: "_EBX DD ?"
+MISMATCH: "_EDX DD ?"
+MISMATCH: "_ECX DD ?"
+MISMATCH: "_EAX DD ?"
+MISMATCH: "_DS DW ?"
+MISMATCH: "_ES DW ?"
+MISMATCH: "_FS DW ?"
+MISMATCH: "_GS DW ?"
+MISMATCH: "_EFLAGS DD ?"
+MISMATCH: "_EIP DD ?"
+MISMATCH: "_CS DW ?"
+MISMATCH: "_SS DW ?"
+MISMATCH: "IA32_REGSS"
+
+MISMATCH: "_STK16 STRUC 1t"
+MISMATCH: "RetEip DD ?"
+MISMATCH: "RetCs DW ?"
+MISMATCH: "ThunkFlags DW ?"
+MISMATCH: "SavedEsp DD ?"
+MISMATCH: "SavedSs DW ?"
+MISMATCH: "SavedGdtr FWORD ?"
+MISMATCH: "SavedCr0 DD ?"
+MISMATCH: "SavedCr4 DD ?"
+MISMATCH: "_STK16S"
+
+.global _InternalAsmThunk16
+MISMATCH: "_InternalAsmThunk16: USES ebp ebx esi edi ds es fs gs"
+MISMATCH: " ASSUME esi:PTR IA32_REGS"
+ movl 36(%esp),%esi
+MISMATCH: " movzx edx, [esi]._SS"
+ movl $[esi]._ESP, %edi
+MISMATCH: " add edi, - sizeof (_STK16) - sizeof (IA32_REGS)"
+ pushl %edi # save stack offset
+ imull $16,%edx,%eax # eax <- edx*16
+ addl %eax,%edi # edi <- linear address of 16-bit stack
+MISMATCH: " push sizeof (IA32_REGS) / 4"
+ popl %ecx
+ rep
+ movsl # copy context to 16-bit stack
+ popl %ebx # ebx <- 16-bit stack offset
+MISMATCH: " mov eax, offset @F "
+ stosl
+ movl %cs,%eax # return segment
+ stosw
+ movl 40(%esp),%eax # THUNK flags
+ stosw
+ movl %esp,%eax
+ stosl # save esp
+ movl %ss,%eax # save ss
+ stosw
+MISMATCH: " sgdt fword ptr [edi] "
+MISMATCH: " sidt fword ptr [esp + 36] "
+ movl %cr0, %esi
+ movl %esi,6(%edi) # save CR0
+MISMATCH: " and esi, NOT 80000001h "
+ movl %cr4, %eax
+ movl %eax,10(%edi) # save CR4
+MISMATCH: " and al, NOT 30h "
+ movl %edx,%edi # edi <- 16-bit stack segment
+ movl 44(%esp),%edx
+ shll $16,%edx
+ pushl %edx
+MISMATCH: " lgdt _16Gdtr "
+ .byte 0xea
+MISMATCH: " DD offset @16Bit"
+ .word 8 # jmp far 8:@16Bit
+@16Bit:
+ movl %esi, %cr0 # disable protected mode
+ movl %eax, %cr4 # disable PAE & PSE
+ lret
+@@:
+ movl %ss,%eax
+ shll $4,%eax
+ addl %esp,%eax # eax <- address of 16-bit stack
+MISMATCH: " lss esp, fword ptr (_STK16 ptr [esp + sizeof (IA32_REGS)]).SavedEsp"
+MISMATCH: " lidt fword ptr [esp + 36] "
+ ret
+
+
+MISMATCH: "_TEXTS"
+
+MISMATCH: "_TEXT16 SEGMENT USE16 "CODE" PARA"
+
+.global _Code16Addr
+MISMATCH: "_Code16Addr: C"
+
+
+.global RealMode
+RealMode:
+MISMATCH: " ASSUME bp:PTR _STK16"
+ movw %di,%ss # set up stack
+ movl %ebx,%esp
+MISMATCH: " lidt fword ptr cs:[_16Idtr - _Code16Addr]"
+ popal
+ popl %ds
+ popl %es
+ popl %fs
+ popl %gs
+ addw $4,%sp # skip EFlags
+MISMATCH: " test (_STK16 ptr [esp + 8]).ThunkFlags, 1"
+ jz @F
+ pushf
+@@:
+ pushw %cs
+MISMATCH: " push @FarCallRet - _Code16Addr"
+ jz @F
+MISMATCH: " jmp fword ptr [esp + 6]"
+@@:
+MISMATCH: " jmp fword ptr [esp + 4]"
+@FarCallRet:
+ pushfl
+ pushw %gs
+ pushw %fs
+ pushw %es
+ pushw %ds
+ pushal
+ cli
+MISMATCH: " lea bp, [esp + sizeof (IA32_REGS)]"
+ .byte 0x66
+MISMATCH: " lgdt [bp].SavedGdtr"
+ movl $[bp].SavedCr4, %eax
+ movl %eax, %cr4
+ movl $[bp].SavedCr0, %eax
+ movl %eax, %cr0 # restore CR0
+MISMATCH: " jmp fword ptr [bp].RetEip"
+
+
+MISMATCH: "_16Idtr FWORD (1 SHL 10) - 1"
+
+_TEXT16:
+
+MISMATCH: "_TEXT16SIZE = _TEXT16- _Code16Addr"
+
+MISMATCH: "_TEXT16S"
+
+
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