mirror of
https://github.com/reactos/reactos.git
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1319 lines
38 KiB
C++
1319 lines
38 KiB
C++
/*
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* Fast486 386/486 CPU Emulation Library
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* common.inl
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*
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* Copyright (C) 2013 Aleksandar Andrejevic <theflash AT sdf DOT lonestar DOT org>
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version 2
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* of the License, or (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
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*/
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#include "common.h"
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/* PUBLIC FUNCTIONS ***********************************************************/
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FORCEINLINE
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INT
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Fast486GetCurrentPrivLevel(PFAST486_STATE State)
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{
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/* Return the CPL, or 3 if we're in virtual 8086 mode */
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return (!State->Flags.Vm) ? State->Cpl : 3;
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}
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FORCEINLINE
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ULONG
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Fast486GetPageTableEntry(PFAST486_STATE State,
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ULONG VirtualAddress,
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BOOLEAN MarkAsDirty)
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{
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ULONG PdeIndex = GET_ADDR_PDE(VirtualAddress);
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ULONG PteIndex = GET_ADDR_PTE(VirtualAddress);
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FAST486_PAGE_DIR DirectoryEntry;
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FAST486_PAGE_TABLE TableEntry;
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ULONG PageDirectory = State->ControlRegisters[FAST486_REG_CR3];
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if ((State->Tlb != NULL)
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&& (State->Tlb[VirtualAddress >> 12] != INVALID_TLB_FIELD))
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{
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/* Return the cached entry */
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return State->Tlb[VirtualAddress >> 12];
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}
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/* Read the directory entry */
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State->MemReadCallback(State,
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PageDirectory + PdeIndex * sizeof(ULONG),
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&DirectoryEntry.Value,
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sizeof(DirectoryEntry));
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/* Make sure it is present */
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if (!DirectoryEntry.Present) return 0;
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/* Was the directory entry accessed before? */
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if (!DirectoryEntry.Accessed)
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{
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/* Well, it is now */
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DirectoryEntry.Accessed = TRUE;
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/* Write back the directory entry */
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State->MemWriteCallback(State,
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PageDirectory + PdeIndex * sizeof(ULONG),
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&DirectoryEntry.Value,
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sizeof(DirectoryEntry));
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}
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/* Read the table entry */
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State->MemReadCallback(State,
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(DirectoryEntry.TableAddress << 12)
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+ PteIndex * sizeof(ULONG),
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&TableEntry.Value,
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sizeof(TableEntry));
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/* Make sure it is present */
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if (!TableEntry.Present) return 0;
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if (MarkAsDirty) TableEntry.Dirty = TRUE;
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/* Was the table entry accessed before? */
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if (!TableEntry.Accessed)
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{
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/* Well, it is now */
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TableEntry.Accessed = TRUE;
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/* Write back the table entry */
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State->MemWriteCallback(State,
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(DirectoryEntry.TableAddress << 12)
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+ PteIndex * sizeof(ULONG),
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&TableEntry.Value,
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sizeof(TableEntry));
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}
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/*
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* The resulting permissions depend on the permissions
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* in the page directory table too
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*/
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TableEntry.Writeable &= DirectoryEntry.Writeable;
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TableEntry.Usermode &= DirectoryEntry.Usermode;
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if (State->Tlb != NULL)
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{
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/* Set the TLB entry */
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State->Tlb[VirtualAddress >> 12] = TableEntry.Value;
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}
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/* Return the table entry */
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return TableEntry.Value;
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}
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FORCEINLINE
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BOOLEAN
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Fast486ReadLinearMemory(PFAST486_STATE State,
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ULONG LinearAddress,
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PVOID Buffer,
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ULONG Size)
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{
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INT Cpl = Fast486GetCurrentPrivLevel(State);
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/* Check if paging is enabled */
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if (State->ControlRegisters[FAST486_REG_CR0] & FAST486_CR0_PG)
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{
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ULONG Page;
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FAST486_PAGE_TABLE TableEntry;
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for (Page = PAGE_ALIGN(LinearAddress);
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Page <= PAGE_ALIGN(LinearAddress + Size - 1);
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Page += PAGE_SIZE)
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{
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ULONG PageOffset = 0, PageLength = PAGE_SIZE;
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/* Get the table entry */
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TableEntry.Value = Fast486GetPageTableEntry(State, Page, FALSE);
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if (!TableEntry.Present || (!TableEntry.Usermode && (Cpl > 0)))
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{
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/* Exception */
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Fast486ExceptionWithErrorCode(State,
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FAST486_EXCEPTION_PF,
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TableEntry.Value & 0x07);
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return FALSE;
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}
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/* Check if this is the first page */
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if (Page == PAGE_ALIGN(LinearAddress))
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{
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/* Start copying from the offset from the beginning of the page */
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PageOffset = PAGE_OFFSET(LinearAddress);
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}
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/* Check if this is the last page */
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if (Page == PAGE_ALIGN(LinearAddress + Size - 1))
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{
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/* Copy only a part of the page */
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PageLength = PAGE_OFFSET(LinearAddress + Size);
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}
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/* Read the memory */
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State->MemReadCallback(State,
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(TableEntry.Address << 12) | PageOffset,
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Buffer,
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PageLength);
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}
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}
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else
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{
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/* Read the memory */
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State->MemReadCallback(State, LinearAddress, Buffer, Size);
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}
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return TRUE;
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}
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FORCEINLINE
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BOOLEAN
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Fast486WriteLinearMemory(PFAST486_STATE State,
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ULONG LinearAddress,
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PVOID Buffer,
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ULONG Size)
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{
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INT Cpl = Fast486GetCurrentPrivLevel(State);
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/* Check if paging is enabled */
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if (State->ControlRegisters[FAST486_REG_CR0] & FAST486_CR0_PG)
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{
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ULONG Page;
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FAST486_PAGE_TABLE TableEntry;
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for (Page = PAGE_ALIGN(LinearAddress);
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Page <= PAGE_ALIGN(LinearAddress + Size - 1);
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Page += PAGE_SIZE)
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{
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ULONG PageOffset = 0, PageLength = PAGE_SIZE;
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/* Get the table entry */
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TableEntry.Value = Fast486GetPageTableEntry(State, Page, TRUE);
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if ((!TableEntry.Present || (!TableEntry.Usermode && (Cpl > 0)))
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|| ((State->ControlRegisters[FAST486_REG_CR0] & FAST486_CR0_WP)
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&& !TableEntry.Writeable))
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{
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/* Exception */
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Fast486ExceptionWithErrorCode(State,
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FAST486_EXCEPTION_PF,
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TableEntry.Value & 0x07);
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return FALSE;
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}
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/* Check if this is the first page */
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if (Page == PAGE_ALIGN(LinearAddress))
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{
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/* Start copying from the offset from the beginning of the page */
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PageOffset = PAGE_OFFSET(LinearAddress);
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}
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/* Check if this is the last page */
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if (Page == PAGE_ALIGN(LinearAddress + Size - 1))
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{
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/* Copy only a part of the page */
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PageLength = PAGE_OFFSET(LinearAddress + Size);
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}
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/* Write the memory */
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State->MemWriteCallback(State,
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(TableEntry.Address << 12) | PageOffset,
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Buffer,
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PageLength);
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}
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}
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else
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{
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/* Write the memory */
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State->MemWriteCallback(State, LinearAddress, Buffer, Size);
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}
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return TRUE;
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}
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FORCEINLINE
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VOID
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Fast486Exception(PFAST486_STATE State,
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FAST486_EXCEPTIONS ExceptionCode)
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{
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/* Call the internal function */
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Fast486ExceptionWithErrorCode(State, ExceptionCode, 0);
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}
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FORCEINLINE
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BOOLEAN
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Fast486StackPush(PFAST486_STATE State,
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ULONG Value)
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{
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BOOLEAN Size = State->SegmentRegs[FAST486_REG_CS].Size;
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/* The OPSIZE prefix toggles the size */
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if (State->PrefixFlags & FAST486_PREFIX_OPSIZE) Size = !Size;
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if (Size)
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{
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/* 32-bit size */
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/* Check if ESP is between 1 and 3 */
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if (State->GeneralRegs[FAST486_REG_ESP].Long >= 1
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&& State->GeneralRegs[FAST486_REG_ESP].Long <= 3)
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{
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Fast486Exception(State, FAST486_EXCEPTION_SS);
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return FALSE;
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}
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/* Subtract ESP by 4 */
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State->GeneralRegs[FAST486_REG_ESP].Long -= 4;
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/* Store the value in SS:ESP */
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return Fast486WriteMemory(State,
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FAST486_REG_SS,
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State->GeneralRegs[FAST486_REG_ESP].Long,
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&Value,
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sizeof(ULONG));
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}
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else
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{
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/* 16-bit size */
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USHORT ShortValue = LOWORD(Value);
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/* Check if SP is 1 */
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if (State->GeneralRegs[FAST486_REG_ESP].Long == 1)
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{
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Fast486Exception(State, FAST486_EXCEPTION_SS);
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return FALSE;
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}
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/* Subtract SP by 2 */
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State->GeneralRegs[FAST486_REG_ESP].LowWord -= 2;
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/* Store the value in SS:SP */
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return Fast486WriteMemory(State,
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FAST486_REG_SS,
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State->GeneralRegs[FAST486_REG_ESP].LowWord,
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&ShortValue,
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sizeof(USHORT));
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}
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}
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FORCEINLINE
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BOOLEAN
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Fast486StackPop(PFAST486_STATE State,
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PULONG Value)
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{
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ULONG LongValue;
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USHORT ShortValue;
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BOOLEAN Size = State->SegmentRegs[FAST486_REG_CS].Size;
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/* The OPSIZE prefix toggles the size */
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TOGGLE_OPSIZE(Size);
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if (Size)
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{
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/* 32-bit size */
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/* Check if ESP is 0xFFFFFFFF */
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if (State->GeneralRegs[FAST486_REG_ESP].Long == 0xFFFFFFFF)
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{
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Fast486Exception(State, FAST486_EXCEPTION_SS);
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return FALSE;
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}
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/* Read the value from SS:ESP */
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if (!Fast486ReadMemory(State,
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FAST486_REG_SS,
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State->GeneralRegs[FAST486_REG_ESP].Long,
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FALSE,
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&LongValue,
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sizeof(LongValue)))
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{
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/* An exception occurred */
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return FALSE;
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}
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/* Increment ESP by 4 */
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State->GeneralRegs[FAST486_REG_ESP].Long += 4;
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/* Store the value in the result */
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*Value = LongValue;
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}
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else
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{
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/* 16-bit size */
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/* Check if SP is 0xFFFF */
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if (State->GeneralRegs[FAST486_REG_ESP].LowWord == 0xFFFF)
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{
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Fast486Exception(State, FAST486_EXCEPTION_SS);
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return FALSE;
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}
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/* Read the value from SS:SP */
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if (!Fast486ReadMemory(State,
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FAST486_REG_SS,
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State->GeneralRegs[FAST486_REG_ESP].LowWord,
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FALSE,
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&ShortValue,
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sizeof(ShortValue)))
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{
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/* An exception occurred */
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return FALSE;
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}
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/* Increment SP by 2 */
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State->GeneralRegs[FAST486_REG_ESP].LowWord += 2;
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/* Store the value in the result */
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*Value = ShortValue;
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}
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return TRUE;
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}
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FORCEINLINE
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BOOLEAN
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Fast486LoadSegment(PFAST486_STATE State,
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INT Segment,
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USHORT Selector)
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{
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PFAST486_SEG_REG CachedDescriptor;
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FAST486_GDT_ENTRY GdtEntry;
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ASSERT(Segment < FAST486_NUM_SEG_REGS);
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/* Get the cached descriptor */
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CachedDescriptor = &State->SegmentRegs[Segment];
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/* Check for protected mode */
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if ((State->ControlRegisters[FAST486_REG_CR0] & FAST486_CR0_PE) && !State->Flags.Vm)
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{
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if (!(Selector & SEGMENT_TABLE_INDICATOR))
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{
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/* Make sure the GDT contains the entry */
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if (GET_SEGMENT_INDEX(Selector) >= (State->Gdtr.Size + 1))
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{
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Fast486ExceptionWithErrorCode(State, FAST486_EXCEPTION_GP, Selector);
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return FALSE;
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}
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/* Read the GDT */
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if (!Fast486ReadLinearMemory(State,
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State->Gdtr.Address
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+ GET_SEGMENT_INDEX(Selector),
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&GdtEntry,
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sizeof(GdtEntry)))
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{
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/* Exception occurred */
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return FALSE;
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}
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}
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else
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{
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/* Make sure the LDT contains the entry */
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if (GET_SEGMENT_INDEX(Selector) >= (State->Ldtr.Size + 1))
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{
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Fast486ExceptionWithErrorCode(State, FAST486_EXCEPTION_GP, Selector);
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return FALSE;
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}
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/* Read the LDT */
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if (!Fast486ReadLinearMemory(State,
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State->Ldtr.Address
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+ GET_SEGMENT_INDEX(Selector),
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&GdtEntry,
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sizeof(GdtEntry)))
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{
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/* Exception occurred */
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return FALSE;
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}
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}
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if (Segment == FAST486_REG_SS)
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{
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/* Loading the stack segment */
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if (GET_SEGMENT_INDEX(Selector) == 0)
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{
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Fast486Exception(State, FAST486_EXCEPTION_GP);
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return FALSE;
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}
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if (!GdtEntry.SystemType)
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{
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/* This is a special descriptor */
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Fast486ExceptionWithErrorCode(State, FAST486_EXCEPTION_GP, Selector);
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return FALSE;
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}
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if (GdtEntry.Executable || !GdtEntry.ReadWrite)
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{
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Fast486ExceptionWithErrorCode(State, FAST486_EXCEPTION_GP, Selector);
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return FALSE;
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}
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if ((GET_SEGMENT_RPL(Selector) != Fast486GetCurrentPrivLevel(State))
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|| (GET_SEGMENT_RPL(Selector) != GdtEntry.Dpl))
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{
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Fast486ExceptionWithErrorCode(State, FAST486_EXCEPTION_GP, Selector);
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return FALSE;
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}
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if (!GdtEntry.Present)
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{
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Fast486ExceptionWithErrorCode(State, FAST486_EXCEPTION_SS, Selector);
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return FALSE;
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}
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}
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else if (Segment == FAST486_REG_CS)
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{
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/* Loading the code segment */
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if (GET_SEGMENT_INDEX(Selector) == 0)
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{
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Fast486Exception(State, FAST486_EXCEPTION_GP);
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return FALSE;
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}
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if (!GdtEntry.SystemType)
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{
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// TODO: Call/interrupt/task gates NOT IMPLEMENTED!
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UNIMPLEMENTED;
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}
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else
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{
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if (!GdtEntry.Present)
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{
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Fast486ExceptionWithErrorCode(State, FAST486_EXCEPTION_NP, Selector);
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return FALSE;
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}
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if (!GdtEntry.Executable)
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{
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Fast486ExceptionWithErrorCode(State, FAST486_EXCEPTION_GP, Selector);
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return FALSE;
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}
|
|
|
|
if (GdtEntry.DirConf)
|
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{
|
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/* Conforming Code Segment */
|
|
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if (GdtEntry.Dpl > Fast486GetCurrentPrivLevel(State))
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{
|
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/* Must be accessed from lower-privileged code */
|
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Fast486ExceptionWithErrorCode(State, FAST486_EXCEPTION_GP, Selector);
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return FALSE;
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}
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}
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else
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{
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/* Regular code segment */
|
|
|
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if ((GET_SEGMENT_RPL(Selector) > Fast486GetCurrentPrivLevel(State))
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|| (Fast486GetCurrentPrivLevel(State) != GdtEntry.Dpl))
|
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{
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Fast486ExceptionWithErrorCode(State, FAST486_EXCEPTION_GP, Selector);
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return FALSE;
|
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}
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|
}
|
|
|
|
/* Update CPL */
|
|
State->Cpl = GET_SEGMENT_RPL(Selector);
|
|
}
|
|
}
|
|
else
|
|
{
|
|
/* Loading a data segment */
|
|
|
|
if (!GdtEntry.SystemType)
|
|
{
|
|
/* This is a special descriptor */
|
|
Fast486ExceptionWithErrorCode(State, FAST486_EXCEPTION_GP, Selector);
|
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return FALSE;
|
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}
|
|
|
|
if ((GET_SEGMENT_RPL(Selector) > GdtEntry.Dpl)
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|| (Fast486GetCurrentPrivLevel(State) > GdtEntry.Dpl))
|
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{
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Fast486ExceptionWithErrorCode(State, FAST486_EXCEPTION_GP, Selector);
|
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return FALSE;
|
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}
|
|
|
|
if (!GdtEntry.Present)
|
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{
|
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Fast486ExceptionWithErrorCode(State, FAST486_EXCEPTION_NP, Selector);
|
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return FALSE;
|
|
}
|
|
}
|
|
|
|
/* Update the cache entry */
|
|
CachedDescriptor->Selector = Selector;
|
|
CachedDescriptor->Base = GdtEntry.Base | (GdtEntry.BaseMid << 16) | (GdtEntry.BaseHigh << 24);
|
|
CachedDescriptor->Limit = GdtEntry.Limit | (GdtEntry.LimitHigh << 16);
|
|
CachedDescriptor->Accessed = GdtEntry.Accessed;
|
|
CachedDescriptor->ReadWrite = GdtEntry.ReadWrite;
|
|
CachedDescriptor->DirConf = GdtEntry.DirConf;
|
|
CachedDescriptor->Executable = GdtEntry.Executable;
|
|
CachedDescriptor->SystemType = GdtEntry.SystemType;
|
|
CachedDescriptor->Dpl = GdtEntry.Dpl;
|
|
CachedDescriptor->Present = GdtEntry.Present;
|
|
CachedDescriptor->Size = GdtEntry.Size;
|
|
|
|
/* Check for page granularity */
|
|
if (GdtEntry.Granularity) CachedDescriptor->Limit <<= 12;
|
|
}
|
|
else
|
|
{
|
|
/* Update the selector and base */
|
|
CachedDescriptor->Selector = Selector;
|
|
CachedDescriptor->Base = Selector << 4;
|
|
}
|
|
|
|
return TRUE;
|
|
}
|
|
|
|
FORCEINLINE
|
|
BOOLEAN
|
|
Fast486FetchByte(PFAST486_STATE State,
|
|
PUCHAR Data)
|
|
{
|
|
PFAST486_SEG_REG CachedDescriptor;
|
|
|
|
/* Get the cached descriptor of CS */
|
|
CachedDescriptor = &State->SegmentRegs[FAST486_REG_CS];
|
|
|
|
/* Read from memory */
|
|
if (!Fast486ReadMemory(State,
|
|
FAST486_REG_CS,
|
|
(CachedDescriptor->Size) ? State->InstPtr.Long
|
|
: State->InstPtr.LowWord,
|
|
TRUE,
|
|
Data,
|
|
sizeof(UCHAR)))
|
|
{
|
|
/* Exception occurred during instruction fetch */
|
|
return FALSE;
|
|
}
|
|
|
|
/* Advance the instruction pointer */
|
|
if (CachedDescriptor->Size) State->InstPtr.Long++;
|
|
else State->InstPtr.LowWord++;
|
|
|
|
return TRUE;
|
|
}
|
|
|
|
FORCEINLINE
|
|
BOOLEAN
|
|
Fast486FetchWord(PFAST486_STATE State,
|
|
PUSHORT Data)
|
|
{
|
|
PFAST486_SEG_REG CachedDescriptor;
|
|
|
|
/* Get the cached descriptor of CS */
|
|
CachedDescriptor = &State->SegmentRegs[FAST486_REG_CS];
|
|
|
|
/* Read from memory */
|
|
// FIXME: Fix byte order on big-endian machines
|
|
if (!Fast486ReadMemory(State,
|
|
FAST486_REG_CS,
|
|
(CachedDescriptor->Size) ? State->InstPtr.Long
|
|
: State->InstPtr.LowWord,
|
|
TRUE,
|
|
Data,
|
|
sizeof(USHORT)))
|
|
{
|
|
/* Exception occurred during instruction fetch */
|
|
return FALSE;
|
|
}
|
|
|
|
/* Advance the instruction pointer */
|
|
if (CachedDescriptor->Size) State->InstPtr.Long += sizeof(USHORT);
|
|
else State->InstPtr.LowWord += sizeof(USHORT);
|
|
|
|
return TRUE;
|
|
}
|
|
|
|
FORCEINLINE
|
|
BOOLEAN
|
|
Fast486FetchDword(PFAST486_STATE State,
|
|
PULONG Data)
|
|
{
|
|
PFAST486_SEG_REG CachedDescriptor;
|
|
|
|
/* Get the cached descriptor of CS */
|
|
CachedDescriptor = &State->SegmentRegs[FAST486_REG_CS];
|
|
|
|
/* Read from memory */
|
|
// FIXME: Fix byte order on big-endian machines
|
|
if (!Fast486ReadMemory(State,
|
|
FAST486_REG_CS,
|
|
(CachedDescriptor->Size) ? State->InstPtr.Long
|
|
: State->InstPtr.LowWord,
|
|
TRUE,
|
|
Data,
|
|
sizeof(ULONG)))
|
|
{
|
|
/* Exception occurred during instruction fetch */
|
|
return FALSE;
|
|
}
|
|
|
|
/* Advance the instruction pointer */
|
|
if (CachedDescriptor->Size) State->InstPtr.Long += sizeof(ULONG);
|
|
else State->InstPtr.LowWord += sizeof(ULONG);
|
|
|
|
return TRUE;
|
|
}
|
|
|
|
FORCEINLINE
|
|
BOOLEAN
|
|
Fast486GetIntVector(PFAST486_STATE State,
|
|
UCHAR Number,
|
|
PFAST486_IDT_ENTRY IdtEntry)
|
|
{
|
|
ULONG FarPointer;
|
|
|
|
/* Check for protected mode */
|
|
if (State->ControlRegisters[FAST486_REG_CR0] & FAST486_CR0_PE)
|
|
{
|
|
/* Read from the IDT */
|
|
if (!Fast486ReadLinearMemory(State,
|
|
State->Idtr.Address
|
|
+ Number * sizeof(*IdtEntry),
|
|
IdtEntry,
|
|
sizeof(*IdtEntry)))
|
|
{
|
|
/* Exception occurred */
|
|
return FALSE;
|
|
}
|
|
}
|
|
else
|
|
{
|
|
/* Read from the real-mode IVT */
|
|
|
|
/* Paging is always disabled in real mode */
|
|
State->MemReadCallback(State,
|
|
State->Idtr.Address
|
|
+ Number * sizeof(FarPointer),
|
|
&FarPointer,
|
|
sizeof(FarPointer));
|
|
|
|
/* Fill a fake IDT entry */
|
|
IdtEntry->Offset = LOWORD(FarPointer);
|
|
IdtEntry->Selector = HIWORD(FarPointer);
|
|
IdtEntry->Zero = 0;
|
|
IdtEntry->Type = FAST486_IDT_INT_GATE;
|
|
IdtEntry->Storage = FALSE;
|
|
IdtEntry->Dpl = 0;
|
|
IdtEntry->Present = TRUE;
|
|
IdtEntry->OffsetHigh = 0;
|
|
}
|
|
|
|
return TRUE;
|
|
}
|
|
|
|
FORCEINLINE
|
|
BOOLEAN
|
|
Fast486CalculateParity(UCHAR Number)
|
|
{
|
|
// See http://graphics.stanford.edu/~seander/bithacks.html#ParityLookupTable too...
|
|
return (0x9669 >> ((Number & 0x0F) ^ (Number >> 4))) & 1;
|
|
}
|
|
|
|
FORCEINLINE
|
|
BOOLEAN
|
|
Fast486ParseModRegRm(PFAST486_STATE State,
|
|
BOOLEAN AddressSize,
|
|
PFAST486_MOD_REG_RM ModRegRm)
|
|
{
|
|
UCHAR ModRmByte, Mode, RegMem;
|
|
|
|
/* Fetch the MOD REG R/M byte */
|
|
if (!Fast486FetchByte(State, &ModRmByte))
|
|
{
|
|
/* Exception occurred */
|
|
return FALSE;
|
|
}
|
|
|
|
/* Unpack the mode and R/M */
|
|
Mode = ModRmByte >> 6;
|
|
RegMem = ModRmByte & 0x07;
|
|
|
|
/* Set the register operand */
|
|
ModRegRm->Register = (ModRmByte >> 3) & 0x07;
|
|
|
|
/* Check the mode */
|
|
if ((ModRmByte >> 6) == 3)
|
|
{
|
|
/* The second operand is also a register */
|
|
ModRegRm->Memory = FALSE;
|
|
ModRegRm->SecondRegister = RegMem;
|
|
|
|
/* Done parsing */
|
|
return TRUE;
|
|
}
|
|
|
|
/* The second operand is memory */
|
|
ModRegRm->Memory = TRUE;
|
|
|
|
if (AddressSize)
|
|
{
|
|
if (RegMem == FAST486_REG_ESP)
|
|
{
|
|
UCHAR SibByte;
|
|
ULONG Scale, Index, Base;
|
|
|
|
/* Fetch the SIB byte */
|
|
if (!Fast486FetchByte(State, &SibByte))
|
|
{
|
|
/* Exception occurred */
|
|
return FALSE;
|
|
}
|
|
|
|
/* Unpack the scale, index and base */
|
|
Scale = 1 << (SibByte >> 6);
|
|
Index = (SibByte >> 3) & 0x07;
|
|
if (Index != FAST486_REG_ESP) Index = State->GeneralRegs[Index].Long;
|
|
else Index = 0;
|
|
|
|
if (((SibByte & 0x07) != FAST486_REG_EBP) || (Mode != 0))
|
|
{
|
|
/* Use the register a base */
|
|
Base = State->GeneralRegs[SibByte & 0x07].Long;
|
|
}
|
|
else
|
|
{
|
|
/* Fetch the base */
|
|
if (!Fast486FetchDword(State, &Base))
|
|
{
|
|
/* Exception occurred */
|
|
return FALSE;
|
|
}
|
|
}
|
|
|
|
if ((SibByte & 0x07) == FAST486_REG_ESP)
|
|
{
|
|
/* Check if there is no segment override */
|
|
if (!(State->PrefixFlags & FAST486_PREFIX_SEG))
|
|
{
|
|
/* Add a SS: prefix */
|
|
State->PrefixFlags |= FAST486_PREFIX_SEG;
|
|
State->SegmentOverride = FAST486_REG_SS;
|
|
}
|
|
}
|
|
|
|
/* Calculate the address */
|
|
ModRegRm->MemoryAddress = Base + Index * Scale;
|
|
}
|
|
else if (RegMem == FAST486_REG_EBP)
|
|
{
|
|
if (Mode) ModRegRm->MemoryAddress = State->GeneralRegs[FAST486_REG_EBP].Long;
|
|
else ModRegRm->MemoryAddress = 0;
|
|
}
|
|
else
|
|
{
|
|
/* Get the base from the register */
|
|
ModRegRm->MemoryAddress = State->GeneralRegs[RegMem].Long;
|
|
}
|
|
|
|
/* Check if there is no segment override */
|
|
if (!(State->PrefixFlags & FAST486_PREFIX_SEG))
|
|
{
|
|
/* Check if the default segment should be SS */
|
|
if ((RegMem == FAST486_REG_EBP) && Mode)
|
|
{
|
|
/* Add a SS: prefix */
|
|
State->PrefixFlags |= FAST486_PREFIX_SEG;
|
|
State->SegmentOverride = FAST486_REG_SS;
|
|
}
|
|
}
|
|
|
|
if (Mode == 1)
|
|
{
|
|
CHAR Offset;
|
|
|
|
/* Fetch the byte */
|
|
if (!Fast486FetchByte(State, (PUCHAR)&Offset))
|
|
{
|
|
/* Exception occurred */
|
|
return FALSE;
|
|
}
|
|
|
|
/* Add the signed offset to the address */
|
|
ModRegRm->MemoryAddress += (LONG)Offset;
|
|
}
|
|
else if ((Mode == 2) || ((Mode == 0) && (RegMem == FAST486_REG_EBP)))
|
|
{
|
|
LONG Offset;
|
|
|
|
/* Fetch the dword */
|
|
if (!Fast486FetchDword(State, (PULONG)&Offset))
|
|
{
|
|
/* Exception occurred */
|
|
return FALSE;
|
|
}
|
|
|
|
/* Add the signed offset to the address */
|
|
ModRegRm->MemoryAddress += Offset;
|
|
}
|
|
}
|
|
else
|
|
{
|
|
/* Check the operand */
|
|
switch (RegMem)
|
|
{
|
|
case 0:
|
|
{
|
|
/* [BX + SI] */
|
|
ModRegRm->MemoryAddress = State->GeneralRegs[FAST486_REG_EBX].LowWord
|
|
+ State->GeneralRegs[FAST486_REG_ESI].LowWord;
|
|
|
|
break;
|
|
}
|
|
|
|
case 1:
|
|
{
|
|
/* [BX + DI] */
|
|
ModRegRm->MemoryAddress = State->GeneralRegs[FAST486_REG_EBX].LowWord
|
|
+ State->GeneralRegs[FAST486_REG_EDI].LowWord;
|
|
|
|
break;
|
|
}
|
|
|
|
case 2:
|
|
{
|
|
/* SS:[BP + SI] */
|
|
ModRegRm->MemoryAddress = State->GeneralRegs[FAST486_REG_EBP].LowWord
|
|
+ State->GeneralRegs[FAST486_REG_ESI].LowWord;
|
|
|
|
break;
|
|
}
|
|
|
|
case 3:
|
|
{
|
|
/* SS:[BP + DI] */
|
|
ModRegRm->MemoryAddress = State->GeneralRegs[FAST486_REG_EBP].LowWord
|
|
+ State->GeneralRegs[FAST486_REG_EDI].LowWord;
|
|
|
|
break;
|
|
}
|
|
|
|
case 4:
|
|
{
|
|
/* [SI] */
|
|
ModRegRm->MemoryAddress = State->GeneralRegs[FAST486_REG_ESI].LowWord;
|
|
|
|
break;
|
|
}
|
|
|
|
case 5:
|
|
{
|
|
/* [DI] */
|
|
ModRegRm->MemoryAddress = State->GeneralRegs[FAST486_REG_EDI].LowWord;
|
|
|
|
break;
|
|
}
|
|
|
|
case 6:
|
|
{
|
|
if (Mode)
|
|
{
|
|
/* [BP] */
|
|
ModRegRm->MemoryAddress = State->GeneralRegs[FAST486_REG_EBP].LowWord;
|
|
}
|
|
else
|
|
{
|
|
/* [constant] (added later) */
|
|
ModRegRm->MemoryAddress = 0;
|
|
}
|
|
|
|
break;
|
|
}
|
|
|
|
case 7:
|
|
{
|
|
/* [BX] */
|
|
ModRegRm->MemoryAddress = State->GeneralRegs[FAST486_REG_EBX].LowWord;
|
|
|
|
break;
|
|
}
|
|
}
|
|
|
|
/* Check if there is no segment override */
|
|
if (!(State->PrefixFlags & FAST486_PREFIX_SEG))
|
|
{
|
|
/* Check if the default segment should be SS */
|
|
if ((RegMem == 2) || (RegMem == 3) || ((RegMem == 6) && Mode))
|
|
{
|
|
/* Add a SS: prefix */
|
|
State->PrefixFlags |= FAST486_PREFIX_SEG;
|
|
State->SegmentOverride = FAST486_REG_SS;
|
|
}
|
|
}
|
|
|
|
if (Mode == 1)
|
|
{
|
|
CHAR Offset;
|
|
|
|
/* Fetch the byte */
|
|
if (!Fast486FetchByte(State, (PUCHAR)&Offset))
|
|
{
|
|
/* Exception occurred */
|
|
return FALSE;
|
|
}
|
|
|
|
/* Add the signed offset to the address */
|
|
ModRegRm->MemoryAddress += (LONG)Offset;
|
|
}
|
|
else if ((Mode == 2) || ((Mode == 0) && (RegMem == 6)))
|
|
{
|
|
SHORT Offset;
|
|
|
|
/* Fetch the word */
|
|
if (!Fast486FetchWord(State, (PUSHORT)&Offset))
|
|
{
|
|
/* Exception occurred */
|
|
return FALSE;
|
|
}
|
|
|
|
/* Add the signed offset to the address */
|
|
ModRegRm->MemoryAddress += (LONG)Offset;
|
|
}
|
|
|
|
/* Clear the top 16 bits */
|
|
ModRegRm->MemoryAddress &= 0x0000FFFF;
|
|
}
|
|
|
|
return TRUE;
|
|
}
|
|
|
|
FORCEINLINE
|
|
BOOLEAN
|
|
Fast486ReadModrmByteOperands(PFAST486_STATE State,
|
|
PFAST486_MOD_REG_RM ModRegRm,
|
|
PUCHAR RegValue,
|
|
PUCHAR RmValue)
|
|
{
|
|
FAST486_SEG_REGS Segment = FAST486_REG_DS;
|
|
|
|
if (RegValue)
|
|
{
|
|
/* Get the register value */
|
|
if (ModRegRm->Register & 0x04)
|
|
{
|
|
/* AH, CH, DH, BH */
|
|
*RegValue = State->GeneralRegs[ModRegRm->Register & 0x03].HighByte;
|
|
}
|
|
else
|
|
{
|
|
/* AL, CL, DL, BL */
|
|
*RegValue = State->GeneralRegs[ModRegRm->Register & 0x03].LowByte;
|
|
}
|
|
}
|
|
|
|
if (RmValue)
|
|
{
|
|
if (!ModRegRm->Memory)
|
|
{
|
|
/* Get the second register value */
|
|
if (ModRegRm->SecondRegister & 0x04)
|
|
{
|
|
/* AH, CH, DH, BH */
|
|
*RmValue = State->GeneralRegs[ModRegRm->SecondRegister & 0x03].HighByte;
|
|
}
|
|
else
|
|
{
|
|
/* AL, CL, DL, BL */
|
|
*RmValue = State->GeneralRegs[ModRegRm->SecondRegister & 0x03].LowByte;
|
|
}
|
|
}
|
|
else
|
|
{
|
|
/* Check for the segment override */
|
|
if (State->PrefixFlags & FAST486_PREFIX_SEG)
|
|
{
|
|
/* Use the override segment instead */
|
|
Segment = State->SegmentOverride;
|
|
}
|
|
|
|
/* Read memory */
|
|
if (!Fast486ReadMemory(State,
|
|
Segment,
|
|
ModRegRm->MemoryAddress,
|
|
FALSE,
|
|
RmValue,
|
|
sizeof(UCHAR)))
|
|
{
|
|
/* Exception occurred */
|
|
return FALSE;
|
|
}
|
|
}
|
|
}
|
|
|
|
return TRUE;
|
|
}
|
|
|
|
FORCEINLINE
|
|
BOOLEAN
|
|
Fast486ReadModrmWordOperands(PFAST486_STATE State,
|
|
PFAST486_MOD_REG_RM ModRegRm,
|
|
PUSHORT RegValue,
|
|
PUSHORT RmValue)
|
|
{
|
|
FAST486_SEG_REGS Segment = FAST486_REG_DS;
|
|
|
|
if (RegValue)
|
|
{
|
|
/* Get the register value */
|
|
*RegValue = State->GeneralRegs[ModRegRm->Register].LowWord;
|
|
}
|
|
|
|
if (RmValue)
|
|
{
|
|
if (!ModRegRm->Memory)
|
|
{
|
|
/* Get the second register value */
|
|
*RmValue = State->GeneralRegs[ModRegRm->SecondRegister].LowWord;
|
|
}
|
|
else
|
|
{
|
|
/* Check for the segment override */
|
|
if (State->PrefixFlags & FAST486_PREFIX_SEG)
|
|
{
|
|
/* Use the override segment instead */
|
|
Segment = State->SegmentOverride;
|
|
}
|
|
|
|
/* Read memory */
|
|
if (!Fast486ReadMemory(State,
|
|
Segment,
|
|
ModRegRm->MemoryAddress,
|
|
FALSE,
|
|
RmValue,
|
|
sizeof(USHORT)))
|
|
{
|
|
/* Exception occurred */
|
|
return FALSE;
|
|
}
|
|
}
|
|
}
|
|
|
|
return TRUE;
|
|
}
|
|
|
|
FORCEINLINE
|
|
BOOLEAN
|
|
Fast486ReadModrmDwordOperands(PFAST486_STATE State,
|
|
PFAST486_MOD_REG_RM ModRegRm,
|
|
PULONG RegValue,
|
|
PULONG RmValue)
|
|
{
|
|
FAST486_SEG_REGS Segment = FAST486_REG_DS;
|
|
|
|
if (RegValue)
|
|
{
|
|
/* Get the register value */
|
|
*RegValue = State->GeneralRegs[ModRegRm->Register].Long;
|
|
}
|
|
|
|
if (RmValue)
|
|
{
|
|
if (!ModRegRm->Memory)
|
|
{
|
|
/* Get the second register value */
|
|
*RmValue = State->GeneralRegs[ModRegRm->SecondRegister].Long;
|
|
}
|
|
else
|
|
{
|
|
/* Check for the segment override */
|
|
if (State->PrefixFlags & FAST486_PREFIX_SEG)
|
|
{
|
|
/* Use the override segment instead */
|
|
Segment = State->SegmentOverride;
|
|
}
|
|
|
|
/* Read memory */
|
|
if (!Fast486ReadMemory(State,
|
|
Segment,
|
|
ModRegRm->MemoryAddress,
|
|
FALSE,
|
|
RmValue,
|
|
sizeof(ULONG)))
|
|
{
|
|
/* Exception occurred */
|
|
return FALSE;
|
|
}
|
|
}
|
|
}
|
|
|
|
return TRUE;
|
|
}
|
|
|
|
FORCEINLINE
|
|
BOOLEAN
|
|
Fast486WriteModrmByteOperands(PFAST486_STATE State,
|
|
PFAST486_MOD_REG_RM ModRegRm,
|
|
BOOLEAN WriteRegister,
|
|
UCHAR Value)
|
|
{
|
|
FAST486_SEG_REGS Segment = FAST486_REG_DS;
|
|
|
|
if (WriteRegister)
|
|
{
|
|
/* Store the value in the register */
|
|
if (ModRegRm->Register & 0x04)
|
|
{
|
|
/* AH, CH, DH, BH */
|
|
State->GeneralRegs[ModRegRm->Register & 0x03].HighByte = Value;
|
|
}
|
|
else
|
|
{
|
|
/* AL, CL, DL, BL */
|
|
State->GeneralRegs[ModRegRm->Register & 0x03].LowByte = Value;
|
|
}
|
|
}
|
|
else
|
|
{
|
|
if (!ModRegRm->Memory)
|
|
{
|
|
/* Store the value in the second register */
|
|
if (ModRegRm->SecondRegister & 0x04)
|
|
{
|
|
/* AH, CH, DH, BH */
|
|
State->GeneralRegs[ModRegRm->SecondRegister & 0x03].HighByte = Value;
|
|
}
|
|
else
|
|
{
|
|
/* AL, CL, DL, BL */
|
|
State->GeneralRegs[ModRegRm->SecondRegister & 0x03].LowByte = Value;
|
|
}
|
|
}
|
|
else
|
|
{
|
|
/* Check for the segment override */
|
|
if (State->PrefixFlags & FAST486_PREFIX_SEG)
|
|
{
|
|
/* Use the override segment instead */
|
|
Segment = State->SegmentOverride;
|
|
}
|
|
|
|
/* Write memory */
|
|
if (!Fast486WriteMemory(State,
|
|
Segment,
|
|
ModRegRm->MemoryAddress,
|
|
&Value,
|
|
sizeof(UCHAR)))
|
|
{
|
|
/* Exception occurred */
|
|
return FALSE;
|
|
}
|
|
}
|
|
}
|
|
|
|
return TRUE;
|
|
}
|
|
|
|
FORCEINLINE
|
|
BOOLEAN
|
|
Fast486WriteModrmWordOperands(PFAST486_STATE State,
|
|
PFAST486_MOD_REG_RM ModRegRm,
|
|
BOOLEAN WriteRegister,
|
|
USHORT Value)
|
|
{
|
|
FAST486_SEG_REGS Segment = FAST486_REG_DS;
|
|
|
|
if (WriteRegister)
|
|
{
|
|
/* Store the value in the register */
|
|
State->GeneralRegs[ModRegRm->Register].LowWord = Value;
|
|
}
|
|
else
|
|
{
|
|
if (!ModRegRm->Memory)
|
|
{
|
|
/* Store the value in the second register */
|
|
State->GeneralRegs[ModRegRm->SecondRegister].LowWord = Value;
|
|
}
|
|
else
|
|
{
|
|
/* Check for the segment override */
|
|
if (State->PrefixFlags & FAST486_PREFIX_SEG)
|
|
{
|
|
/* Use the override segment instead */
|
|
Segment = State->SegmentOverride;
|
|
}
|
|
|
|
/* Write memory */
|
|
if (!Fast486WriteMemory(State,
|
|
Segment,
|
|
ModRegRm->MemoryAddress,
|
|
&Value,
|
|
sizeof(USHORT)))
|
|
{
|
|
/* Exception occurred */
|
|
return FALSE;
|
|
}
|
|
}
|
|
}
|
|
|
|
return TRUE;
|
|
}
|
|
|
|
FORCEINLINE
|
|
BOOLEAN
|
|
Fast486WriteModrmDwordOperands(PFAST486_STATE State,
|
|
PFAST486_MOD_REG_RM ModRegRm,
|
|
BOOLEAN WriteRegister,
|
|
ULONG Value)
|
|
{
|
|
FAST486_SEG_REGS Segment = FAST486_REG_DS;
|
|
|
|
if (WriteRegister)
|
|
{
|
|
/* Store the value in the register */
|
|
State->GeneralRegs[ModRegRm->Register].Long = Value;
|
|
}
|
|
else
|
|
{
|
|
if (!ModRegRm->Memory)
|
|
{
|
|
/* Store the value in the second register */
|
|
State->GeneralRegs[ModRegRm->SecondRegister].Long = Value;
|
|
}
|
|
else
|
|
{
|
|
/* Check for the segment override */
|
|
if (State->PrefixFlags & FAST486_PREFIX_SEG)
|
|
{
|
|
/* Use the override segment instead */
|
|
Segment = State->SegmentOverride;
|
|
}
|
|
|
|
/* Write memory */
|
|
if (!Fast486WriteMemory(State,
|
|
Segment,
|
|
ModRegRm->MemoryAddress,
|
|
&Value,
|
|
sizeof(ULONG)))
|
|
{
|
|
/* Exception occurred */
|
|
return FALSE;
|
|
}
|
|
}
|
|
}
|
|
|
|
return TRUE;
|
|
}
|
|
|
|
/* EOF */
|