mirror of https://github.com/acidanthera/audk.git
50 lines
1.1 KiB
NASM
50 lines
1.1 KiB
NASM
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;------------------------------------------------------------------------------
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; @file
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; An entry point use by Xen when a guest is started in PVH mode.
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;
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; Copyright (c) 2019, Citrix Systems, Inc.
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;
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; SPDX-License-Identifier: BSD-2-Clause-Patent
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;
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;------------------------------------------------------------------------------
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BITS 32
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xenPVHMain:
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;
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; 'BP' to indicate boot-strap processor
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;
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mov di, 'BP'
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;
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; ESP will be used as initial value of the EAX register
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; in Main.asm
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;
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xor esp, esp
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mov ebx, ADDR_OF(gdtr)
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lgdt [ebx]
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mov eax, SEC_DEFAULT_CR0
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mov cr0, eax
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jmp LINEAR_CODE_SEL:ADDR_OF(.jmpToNewCodeSeg)
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.jmpToNewCodeSeg:
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mov eax, SEC_DEFAULT_CR4
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mov cr4, eax
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mov ax, LINEAR_SEL
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mov ds, ax
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mov es, ax
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mov fs, ax
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mov gs, ax
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mov ss, ax
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;
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; Jump to the main routine of the pre-SEC code
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; skiping the 16-bit part of the routine and
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; into the 32-bit flat mode part
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;
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OneTimeCallRet TransitionFromReal16To32BitFlat
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