mirror of https://github.com/acidanthera/audk.git
227 lines
7.3 KiB
C
227 lines
7.3 KiB
C
/** @file
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Provide legacy thunk interface for accessing Bios Video Rom.
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Copyright (c) 2006 - 2007, Intel Corporation
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All rights reserved. This program and the accompanying materials
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are licensed and made available under the terms and conditions of the BSD License
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which accompanies this distribution. The full text of the license may be found at
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http://opensource.org/licenses/bsd-license.php
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THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
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WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
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**/
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#include "BiosVideo.h"
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#define EFI_CPU_EFLAGS_IF 0x200
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/**
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Initialize legacy environment for BIOS INI caller.
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@param ThunkContext the instance pointer of THUNK_CONTEXT
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**/
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VOID
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InitializeBiosIntCaller (
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THUNK_CONTEXT *ThunkContext
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)
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{
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EFI_STATUS Status;
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UINT32 RealModeBufferSize;
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UINT32 ExtraStackSize;
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EFI_PHYSICAL_ADDRESS LegacyRegionBase;
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//
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// Get LegacyRegion
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//
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AsmGetThunk16Properties (&RealModeBufferSize, &ExtraStackSize);
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LegacyRegionBase = 0x100000;
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Status = gBS->AllocatePages (
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AllocateMaxAddress,
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EfiACPIMemoryNVS,
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EFI_SIZE_TO_PAGES(RealModeBufferSize + ExtraStackSize + 200),
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&LegacyRegionBase
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);
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ASSERT_EFI_ERROR (Status);
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ThunkContext->RealModeBuffer = (VOID*)(UINTN)LegacyRegionBase;
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ThunkContext->RealModeBufferSize = EFI_PAGES_TO_SIZE (RealModeBufferSize);
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ThunkContext->ThunkAttributes = 3;
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AsmPrepareThunk16(ThunkContext);
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}
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/**
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Initialize interrupt redirection code and entries, because
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IDT Vectors 0x68-0x6f must be redirected to IDT Vectors 0x08-0x0f.
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Or the interrupt will lost when we do thunk.
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NOTE: We do not reset 8259 vector base, because it will cause pending
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interrupt lost.
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@param Legacy8259 Instance pointer for EFI_LEGACY_8259_PROTOCOL.
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**/
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VOID
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InitializeInterruptRedirection (
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IN EFI_LEGACY_8259_PROTOCOL *Legacy8259
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)
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{
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EFI_STATUS Status;
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EFI_PHYSICAL_ADDRESS LegacyRegionBase;
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UINTN LegacyRegionLength;
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UINT32 *IdtArray;
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UINTN Index;
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UINT8 ProtectedModeBaseVector;
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UINT32 InterruptRedirectionCode[] = {
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0x90CF08CD, // INT8; IRET; NOP
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0x90CF09CD, // INT9; IRET; NOP
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0x90CF0ACD, // INTA; IRET; NOP
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0x90CF0BCD, // INTB; IRET; NOP
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0x90CF0CCD, // INTC; IRET; NOP
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0x90CF0DCD, // INTD; IRET; NOP
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0x90CF0ECD, // INTE; IRET; NOP
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0x90CF0FCD // INTF; IRET; NOP
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};
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//
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// Get LegacyRegion
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//
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LegacyRegionLength = sizeof(InterruptRedirectionCode);
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LegacyRegionBase = 0x100000;
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Status = gBS->AllocatePages (
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AllocateMaxAddress,
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EfiACPIMemoryNVS,
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EFI_SIZE_TO_PAGES(LegacyRegionLength),
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&LegacyRegionBase
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);
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ASSERT_EFI_ERROR (Status);
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//
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// Copy code to legacy region
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//
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CopyMem ((VOID *)(UINTN)LegacyRegionBase, InterruptRedirectionCode, sizeof (InterruptRedirectionCode));
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//
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// Get VectorBase, it should be 0x68
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//
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Status = Legacy8259->GetVector (Legacy8259, Efi8259Irq0, &ProtectedModeBaseVector);
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ASSERT_EFI_ERROR (Status);
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//
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// Patch IVT 0x68 ~ 0x6f
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//
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IdtArray = (UINT32 *) 0;
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for (Index = 0; Index < 8; Index++) {
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IdtArray[ProtectedModeBaseVector + Index] = ((EFI_SEGMENT (LegacyRegionBase + Index * 4)) << 16) | (EFI_OFFSET (LegacyRegionBase + Index * 4));
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}
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return ;
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}
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/**
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Thunk to 16-bit real mode and execute a software interrupt with a vector
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of BiosInt. Regs will contain the 16-bit register context on entry and
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exit.
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@param This Protocol instance pointer.
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@param BiosInt Processor interrupt vector to invoke
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@param Reg Register contexted passed into (and returned) from thunk to 16-bit mode
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@retval TRUE Thunk completed, and there were no BIOS errors in the target code.
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See Regs for status.
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@retval FALSE There was a BIOS erro in the target code.
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**/
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BOOLEAN
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EFIAPI
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LegacyBiosInt86 (
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IN BIOS_VIDEO_DEV *BiosDev,
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IN UINT8 BiosInt,
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IN IA32_REGISTER_SET *Regs
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)
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{
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UINTN Status;
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UINTN Eflags;
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IA32_REGISTER_SET ThunkRegSet;
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BOOLEAN Ret;
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UINT16 *Stack16;
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ZeroMem (&ThunkRegSet, sizeof (ThunkRegSet));
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ThunkRegSet.E.EFLAGS.Bits.Reserved_0 = 1;
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ThunkRegSet.E.EFLAGS.Bits.Reserved_1 = 0;
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ThunkRegSet.E.EFLAGS.Bits.Reserved_2 = 0;
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ThunkRegSet.E.EFLAGS.Bits.Reserved_3 = 0;
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ThunkRegSet.E.EFLAGS.Bits.IOPL = 3;
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ThunkRegSet.E.EFLAGS.Bits.NT = 0;
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ThunkRegSet.E.EFLAGS.Bits.IF = 1;
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ThunkRegSet.E.EFLAGS.Bits.TF = 0;
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ThunkRegSet.E.EFLAGS.Bits.CF = 0;
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ThunkRegSet.E.EDI = Regs->E.EDI;
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ThunkRegSet.E.ESI = Regs->E.ESI;
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ThunkRegSet.E.EBP = Regs->E.EBP;
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ThunkRegSet.E.EBX = Regs->E.EBX;
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ThunkRegSet.E.EDX = Regs->E.EDX;
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ThunkRegSet.E.ECX = Regs->E.ECX;
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ThunkRegSet.E.EAX = Regs->E.EAX;
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ThunkRegSet.E.DS = Regs->E.DS;
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ThunkRegSet.E.ES = Regs->E.ES;
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//
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// The call to Legacy16 is a critical section to EFI
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//
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Eflags = AsmReadEflags ();
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if ((Eflags | EFI_CPU_EFLAGS_IF) != 0) {
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DisableInterrupts ();
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}
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//
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// Set Legacy16 state. 0x08, 0x70 is legacy 8259 vector bases.
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//
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Status = BiosDev->Legacy8259->SetMode (BiosDev->Legacy8259, Efi8259LegacyMode, NULL, NULL);
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ASSERT_EFI_ERROR (Status);
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Stack16 = (UINT16 *)((UINT8 *) BiosDev->ThunkContext->RealModeBuffer + BiosDev->ThunkContext->RealModeBufferSize - sizeof (UINT16));
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ThunkRegSet.E.SS = (UINT16) (((UINTN) Stack16 >> 16) << 12);
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ThunkRegSet.E.ESP = (UINT16) (UINTN) Stack16;
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ThunkRegSet.E.Eip = (UINT16)((UINT32 *)NULL)[BiosInt];
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ThunkRegSet.E.CS = (UINT16)(((UINT32 *)NULL)[BiosInt] >> 16);
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BiosDev->ThunkContext->RealModeState = &ThunkRegSet;
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AsmThunk16 (BiosDev->ThunkContext);
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//
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// Restore protected mode interrupt state
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//
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Status = BiosDev->Legacy8259->SetMode (BiosDev->Legacy8259, Efi8259ProtectedMode, NULL, NULL);
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ASSERT_EFI_ERROR (Status);
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//
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// End critical section
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//
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if ((Eflags | EFI_CPU_EFLAGS_IF) != 0) {
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EnableInterrupts ();
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}
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Regs->E.EDI = ThunkRegSet.E.EDI;
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Regs->E.ESI = ThunkRegSet.E.ESI;
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Regs->E.EBP = ThunkRegSet.E.EBP;
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Regs->E.EBX = ThunkRegSet.E.EBX;
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Regs->E.EDX = ThunkRegSet.E.EDX;
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Regs->E.ECX = ThunkRegSet.E.ECX;
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Regs->E.EAX = ThunkRegSet.E.EAX;
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Regs->E.SS = ThunkRegSet.E.SS;
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Regs->E.CS = ThunkRegSet.E.CS;
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Regs->E.DS = ThunkRegSet.E.DS;
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Regs->E.ES = ThunkRegSet.E.ES;
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CopyMem (&(Regs->E.EFLAGS), &(ThunkRegSet.E.EFLAGS), sizeof (UINT32));
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Ret = (BOOLEAN) (Regs->E.EFLAGS.Bits.CF == 1);
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return Ret;
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}
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