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5f874178e7
Implement helper functions for reading/writing operands of instructions that use the MOD-REG-R/M byte. Implement the MOD-REG-R/M ADD instruction for bytes. svn path=/branches/ntvdm/; revision=59981
1291 lines
35 KiB
C
1291 lines
35 KiB
C
/*
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* COPYRIGHT: GPL - See COPYING in the top level directory
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* PROJECT: 386/486 CPU Emulation Library
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* FILE: common.c
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* PURPOSE: Common functions used internally by Soft386.
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* PROGRAMMERS: Aleksandar Andrejevic <theflash AT sdf DOT lonestar DOT org>
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*/
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/* INCLUDES *******************************************************************/
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// #define WIN32_NO_STATUS
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// #define _INC_WINDOWS
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#include <windef.h>
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#include <soft386.h>
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#include "common.h"
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// #define NDEBUG
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#include <debug.h>
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/* PRIVATE FUNCTIONS **********************************************************/
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static
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inline
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INT
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Soft386GetCurrentPrivLevel(PSOFT386_STATE State)
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{
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return GET_SEGMENT_RPL(State->SegmentRegs[SOFT386_REG_CS].Selector);
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}
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/* PUBLIC FUNCTIONS ***********************************************************/
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inline
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BOOLEAN
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Soft386ReadMemory(PSOFT386_STATE State,
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INT SegmentReg,
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ULONG Offset,
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BOOLEAN InstFetch,
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PVOID Buffer,
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ULONG Size)
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{
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ULONG LinearAddress;
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PSOFT386_SEG_REG CachedDescriptor;
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ASSERT(SegmentReg < SOFT386_NUM_SEG_REGS);
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/* Get the cached descriptor */
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CachedDescriptor = &State->SegmentRegs[SegmentReg];
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if ((Offset + Size) >= CachedDescriptor->Limit)
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{
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/* Read beyond limit */
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Soft386Exception(State, SOFT386_EXCEPTION_GP);
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return FALSE;
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}
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/* Check for protected mode */
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if (State->ControlRegisters[0] & SOFT386_CR0_PE)
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{
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/* Privilege checks */
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if (!CachedDescriptor->Present)
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{
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Soft386Exception(State, SOFT386_EXCEPTION_NP);
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return FALSE;
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}
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if (GET_SEGMENT_RPL(CachedDescriptor->Selector) > CachedDescriptor->Dpl)
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{
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Soft386Exception(State, SOFT386_EXCEPTION_GP);
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return FALSE;
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}
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if (InstFetch)
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{
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if (!CachedDescriptor->Executable)
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{
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/* Data segment not executable */
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Soft386Exception(State, SOFT386_EXCEPTION_GP);
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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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if (CachedDescriptor->Executable && (!CachedDescriptor->ReadWrite))
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{
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/* Code segment not readable */
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Soft386Exception(State, SOFT386_EXCEPTION_GP);
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return FALSE;
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}
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}
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}
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/* Find the linear address */
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LinearAddress = CachedDescriptor->Base + Offset;
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// TODO: Paging support!
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/* Did the host provide a memory hook? */
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if (State->MemReadCallback)
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{
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/* Yes, call the host */
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State->MemReadCallback(State, LinearAddress, Buffer, Size);
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}
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else
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{
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/* Read the memory directly */
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RtlMoveMemory(Buffer, (PVOID)LinearAddress, Size);
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}
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return TRUE;
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}
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inline
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BOOLEAN
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Soft386WriteMemory(PSOFT386_STATE State,
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INT SegmentReg,
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ULONG Offset,
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PVOID Buffer,
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ULONG Size)
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{
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ULONG LinearAddress;
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PSOFT386_SEG_REG CachedDescriptor;
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ASSERT(SegmentReg < SOFT386_NUM_SEG_REGS);
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/* Get the cached descriptor */
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CachedDescriptor = &State->SegmentRegs[SegmentReg];
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if ((Offset + Size) >= CachedDescriptor->Limit)
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{
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/* Write beyond limit */
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Soft386Exception(State, SOFT386_EXCEPTION_GP);
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return FALSE;
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}
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/* Check for protected mode */
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if (State->ControlRegisters[0] & SOFT386_CR0_PE)
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{
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/* Privilege checks */
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if (!CachedDescriptor->Present)
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{
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Soft386Exception(State, SOFT386_EXCEPTION_NP);
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return FALSE;
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}
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if (GET_SEGMENT_RPL(CachedDescriptor->Selector) > CachedDescriptor->Dpl)
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{
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Soft386Exception(State, SOFT386_EXCEPTION_GP);
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return FALSE;
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}
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if (CachedDescriptor->Executable)
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{
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/* Code segment not writable */
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Soft386Exception(State, SOFT386_EXCEPTION_GP);
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return FALSE;
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}
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else if (!CachedDescriptor->ReadWrite)
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{
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/* Data segment not writeable */
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Soft386Exception(State, SOFT386_EXCEPTION_GP);
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return FALSE;
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}
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}
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/* Find the linear address */
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LinearAddress = CachedDescriptor->Base + Offset;
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// TODO: Paging support!
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/* Did the host provide a memory hook? */
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if (State->MemWriteCallback)
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{
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/* Yes, call the host */
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State->MemWriteCallback(State, LinearAddress, Buffer, Size);
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}
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else
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{
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/* Write the memory directly */
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RtlMoveMemory((PVOID)LinearAddress, Buffer, Size);
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}
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return TRUE;
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}
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inline
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BOOLEAN
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Soft386StackPush(PSOFT386_STATE State, ULONG Value)
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{
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BOOLEAN Size = State->SegmentRegs[SOFT386_REG_SS].Size;
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/* The OPSIZE prefix toggles the size */
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if (State->PrefixFlags & SOFT386_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[SOFT386_REG_ESP].Long >= 1
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&& State->GeneralRegs[SOFT386_REG_ESP].Long <= 3)
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{
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Soft386Exception(State, SOFT386_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[SOFT386_REG_ESP].Long -= 4;
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/* Store the value in SS:ESP */
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return Soft386WriteMemory(State,
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SOFT386_REG_SS,
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State->GeneralRegs[SOFT386_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[SOFT386_REG_ESP].Long == 1)
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{
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Soft386Exception(State, SOFT386_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[SOFT386_REG_ESP].LowWord -= 2;
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/* Store the value in SS:SP */
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return Soft386WriteMemory(State,
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SOFT386_REG_SS,
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State->GeneralRegs[SOFT386_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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inline
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BOOLEAN
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Soft386StackPop(PSOFT386_STATE State, 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[SOFT386_REG_SS].Size;
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/* The OPSIZE prefix toggles the size */
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if (State->PrefixFlags & SOFT386_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 0xFFFFFFFF */
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if (State->GeneralRegs[SOFT386_REG_ESP].Long == 0xFFFFFFFF)
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{
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Soft386Exception(State, SOFT386_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 (!Soft386ReadMemory(State,
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SOFT386_REG_SS,
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State->GeneralRegs[SOFT386_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[SOFT386_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[SOFT386_REG_ESP].LowWord == 0xFFFF)
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{
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Soft386Exception(State, SOFT386_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 (!Soft386ReadMemory(State,
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SOFT386_REG_SS,
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State->GeneralRegs[SOFT386_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[SOFT386_REG_ESP].Long += 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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inline
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BOOLEAN
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Soft386LoadSegment(PSOFT386_STATE State, INT Segment, USHORT Selector)
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{
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PSOFT386_SEG_REG CachedDescriptor;
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SOFT386_GDT_ENTRY GdtEntry;
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ASSERT(Segment < SOFT386_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[SOFT386_REG_CR0] & SOFT386_CR0_PE)
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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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Soft386Exception(State, SOFT386_EXCEPTION_GP);
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return FALSE;
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}
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/* Read the GDT */
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// FIXME: This code is only correct when paging is disabled!!!
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if (State->MemReadCallback)
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{
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State->MemReadCallback(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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else
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{
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RtlMoveMemory(&GdtEntry,
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(PVOID)(State->Gdtr.Address
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+ GET_SEGMENT_INDEX(Selector)),
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sizeof(GdtEntry));
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}
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/* Check if we are loading SS */
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if (Segment == SOFT386_REG_SS)
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{
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if (GET_SEGMENT_INDEX(Selector) == 0)
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{
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Soft386Exception(State, SOFT386_EXCEPTION_GP);
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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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Soft386Exception(State, SOFT386_EXCEPTION_GP);
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return FALSE;
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}
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if ((GET_SEGMENT_RPL(Selector) != Soft386GetCurrentPrivLevel(State))
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|| (GET_SEGMENT_RPL(Selector) != GdtEntry.Dpl))
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{
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Soft386Exception(State, SOFT386_EXCEPTION_GP);
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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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Soft386Exception(State, SOFT386_EXCEPTION_SS);
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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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if ((GET_SEGMENT_RPL(Selector) > GdtEntry.Dpl)
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&& (Soft386GetCurrentPrivLevel(State) > GdtEntry.Dpl))
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{
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Soft386Exception(State, SOFT386_EXCEPTION_GP);
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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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Soft386Exception(State, SOFT386_EXCEPTION_NP);
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return FALSE;
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}
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}
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/* Update the cache entry */
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CachedDescriptor->Selector = Selector;
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CachedDescriptor->Base = GdtEntry.Base | (GdtEntry.BaseHigh << 24);
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CachedDescriptor->Limit = GdtEntry.Limit | (GdtEntry.LimitHigh << 16);
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CachedDescriptor->Accessed = GdtEntry.Accessed;
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CachedDescriptor->ReadWrite = GdtEntry.ReadWrite;
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CachedDescriptor->DirConf = GdtEntry.DirConf;
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CachedDescriptor->Executable = GdtEntry.Executable;
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CachedDescriptor->SystemType = GdtEntry.SystemType;
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CachedDescriptor->Dpl = GdtEntry.Dpl;
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CachedDescriptor->Present = GdtEntry.Present;
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CachedDescriptor->Size = GdtEntry.Size;
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/* Check for page granularity */
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if (GdtEntry.Granularity) CachedDescriptor->Limit <<= 12;
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}
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else
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{
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/* Update the selector and base */
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CachedDescriptor->Selector = Selector;
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CachedDescriptor->Base = Selector << 4;
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}
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return TRUE;
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}
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inline
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BOOLEAN
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Soft386FetchByte(PSOFT386_STATE State, PUCHAR Data)
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{
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PSOFT386_SEG_REG CachedDescriptor;
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/* Get the cached descriptor of CS */
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CachedDescriptor = &State->SegmentRegs[SOFT386_REG_CS];
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/* Read from memory */
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if (!Soft386ReadMemory(State,
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SOFT386_REG_CS,
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(CachedDescriptor->Size) ? State->InstPtr.Long
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: State->InstPtr.LowWord,
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TRUE,
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Data,
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sizeof(UCHAR)))
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{
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/* Exception occurred during instruction fetch */
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return FALSE;
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}
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/* Advance the instruction pointer */
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if (CachedDescriptor->Size) State->InstPtr.Long++;
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else State->InstPtr.LowWord++;
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return TRUE;
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}
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inline
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BOOLEAN
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Soft386FetchWord(PSOFT386_STATE State, PUSHORT Data)
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{
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PSOFT386_SEG_REG CachedDescriptor;
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/* Get the cached descriptor of CS */
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CachedDescriptor = &State->SegmentRegs[SOFT386_REG_CS];
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/* Read from memory */
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// FIXME: Fix byte order on big-endian machines
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if (!Soft386ReadMemory(State,
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SOFT386_REG_CS,
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(CachedDescriptor->Size) ? State->InstPtr.Long
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: State->InstPtr.LowWord,
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TRUE,
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Data,
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sizeof(USHORT)))
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{
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/* Exception occurred during instruction fetch */
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return FALSE;
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}
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/* Advance the instruction pointer */
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if (CachedDescriptor->Size) State->InstPtr.Long += sizeof(USHORT);
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else State->InstPtr.LowWord += sizeof(USHORT);
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return TRUE;
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}
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inline
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BOOLEAN
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Soft386FetchDword(PSOFT386_STATE State, PULONG Data)
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{
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PSOFT386_SEG_REG CachedDescriptor;
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/* Get the cached descriptor of CS */
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CachedDescriptor = &State->SegmentRegs[SOFT386_REG_CS];
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|
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/* Read from memory */
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// FIXME: Fix byte order on big-endian machines
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if (!Soft386ReadMemory(State,
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SOFT386_REG_CS,
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(CachedDescriptor->Size) ? State->InstPtr.Long
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: State->InstPtr.LowWord,
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TRUE,
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Data,
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sizeof(ULONG)))
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{
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/* Exception occurred during instruction fetch */
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return FALSE;
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}
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/* Advance the instruction pointer */
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if (CachedDescriptor->Size) State->InstPtr.Long += sizeof(ULONG);
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else State->InstPtr.LowWord += sizeof(ULONG);
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return TRUE;
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}
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|
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inline
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BOOLEAN
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Soft386InterruptInternal(PSOFT386_STATE State,
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USHORT SegmentSelector,
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ULONG Offset,
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BOOLEAN InterruptGate)
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{
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/* Check for protected mode */
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if (State->ControlRegisters[SOFT386_REG_CR0] & SOFT386_CR0_PE)
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{
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SOFT386_TSS Tss;
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USHORT OldSs = State->SegmentRegs[SOFT386_REG_SS].Selector;
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ULONG OldEsp = State->GeneralRegs[SOFT386_REG_ESP].Long;
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/* Check if the interrupt handler is more privileged */
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if (Soft386GetCurrentPrivLevel(State) > GET_SEGMENT_RPL(SegmentSelector))
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{
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/* Read the TSS */
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// FIXME: This code is only correct when paging is disabled!!!
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if (State->MemReadCallback)
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{
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State->MemReadCallback(State,
|
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State->Tss.Address,
|
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&Tss,
|
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sizeof(Tss));
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}
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else
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{
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RtlMoveMemory(&Tss, (PVOID)State->Tss.Address, sizeof(Tss));
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}
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|
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/* Check the new (higher) privilege level */
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switch (GET_SEGMENT_RPL(SegmentSelector))
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{
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case 0:
|
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{
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if (!Soft386LoadSegment(State, SOFT386_REG_SS, Tss.Ss0))
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{
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/* Exception occurred */
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return FALSE;
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}
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State->GeneralRegs[SOFT386_REG_ESP].Long = Tss.Esp0;
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break;
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}
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case 1:
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{
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if (!Soft386LoadSegment(State, SOFT386_REG_SS, Tss.Ss1))
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{
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/* Exception occurred */
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return FALSE;
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}
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State->GeneralRegs[SOFT386_REG_ESP].Long = Tss.Esp1;
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break;
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}
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case 2:
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{
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if (!Soft386LoadSegment(State, SOFT386_REG_SS, Tss.Ss2))
|
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{
|
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/* Exception occurred */
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|
return FALSE;
|
|
}
|
|
State->GeneralRegs[SOFT386_REG_ESP].Long = Tss.Esp2;
|
|
|
|
break;
|
|
}
|
|
|
|
default:
|
|
{
|
|
/* Should never reach here! */
|
|
ASSERT(FALSE);
|
|
}
|
|
}
|
|
|
|
/* Push SS selector */
|
|
if (!Soft386StackPush(State, OldSs)) return FALSE;
|
|
|
|
/* Push stack pointer */
|
|
if (!Soft386StackPush(State, OldEsp)) return FALSE;
|
|
}
|
|
}
|
|
|
|
/* Push EFLAGS */
|
|
if (!Soft386StackPush(State, State->Flags.Long)) return FALSE;
|
|
|
|
/* Push CS selector */
|
|
if (!Soft386StackPush(State, State->SegmentRegs[SOFT386_REG_CS].Selector)) return FALSE;
|
|
|
|
/* Push the instruction pointer */
|
|
if (!Soft386StackPush(State, State->InstPtr.Long)) return FALSE;
|
|
|
|
if (InterruptGate)
|
|
{
|
|
/* Disable interrupts after a jump to an interrupt gate handler */
|
|
State->Flags.If = FALSE;
|
|
}
|
|
|
|
/* Load new CS */
|
|
if (!Soft386LoadSegment(State, SOFT386_REG_CS, SegmentSelector))
|
|
{
|
|
/* An exception occurred during the jump */
|
|
return FALSE;
|
|
}
|
|
|
|
if (State->SegmentRegs[SOFT386_REG_CS].Size)
|
|
{
|
|
/* 32-bit code segment, use EIP */
|
|
State->InstPtr.Long = Offset;
|
|
}
|
|
else
|
|
{
|
|
/* 16-bit code segment, use IP */
|
|
State->InstPtr.LowWord = LOWORD(Offset);
|
|
}
|
|
|
|
return TRUE;
|
|
}
|
|
|
|
inline
|
|
BOOLEAN
|
|
Soft386GetIntVector(PSOFT386_STATE State,
|
|
UCHAR Number,
|
|
PSOFT386_IDT_ENTRY IdtEntry)
|
|
{
|
|
ULONG FarPointer;
|
|
|
|
/* Check for protected mode */
|
|
if (State->ControlRegisters[SOFT386_REG_CR0] & SOFT386_CR0_PE)
|
|
{
|
|
/* Read from the IDT */
|
|
// FIXME: This code is only correct when paging is disabled!!!
|
|
if (State->MemReadCallback)
|
|
{
|
|
State->MemReadCallback(State,
|
|
State->Idtr.Address
|
|
+ Number * sizeof(*IdtEntry),
|
|
IdtEntry,
|
|
sizeof(*IdtEntry));
|
|
}
|
|
else
|
|
{
|
|
RtlMoveMemory(IdtEntry,
|
|
(PVOID)(State->Idtr.Address
|
|
+ Number * sizeof(*IdtEntry)),
|
|
sizeof(*IdtEntry));
|
|
}
|
|
}
|
|
else
|
|
{
|
|
/* Read from the real-mode IVT */
|
|
|
|
/* Paging is always disabled in real mode */
|
|
if (State->MemReadCallback)
|
|
{
|
|
State->MemReadCallback(State,
|
|
State->Idtr.Address
|
|
+ Number * sizeof(FarPointer),
|
|
&FarPointer,
|
|
sizeof(FarPointer));
|
|
}
|
|
else
|
|
{
|
|
RtlMoveMemory(IdtEntry,
|
|
(PVOID)(State->Idtr.Address
|
|
+ Number * sizeof(FarPointer)),
|
|
sizeof(FarPointer));
|
|
}
|
|
|
|
/* Fill a fake IDT entry */
|
|
IdtEntry->Offset = LOWORD(FarPointer);
|
|
IdtEntry->Selector = HIWORD(FarPointer);
|
|
IdtEntry->Zero = 0;
|
|
IdtEntry->Type = SOFT386_IDT_INT_GATE;
|
|
IdtEntry->Storage = FALSE;
|
|
IdtEntry->Dpl = 0;
|
|
IdtEntry->Present = TRUE;
|
|
IdtEntry->OffsetHigh = 0;
|
|
}
|
|
|
|
/*
|
|
* Once paging support is implemented this function
|
|
* will not always return true
|
|
*/
|
|
return TRUE;
|
|
}
|
|
|
|
VOID
|
|
FASTCALL
|
|
Soft386Exception(PSOFT386_STATE State, INT ExceptionCode)
|
|
{
|
|
SOFT386_IDT_ENTRY IdtEntry;
|
|
|
|
/* Increment the exception count */
|
|
State->ExceptionCount++;
|
|
|
|
/* Check if the exception occurred more than once */
|
|
if (State->ExceptionCount > 1)
|
|
{
|
|
/* Then this is a double fault */
|
|
ExceptionCode = SOFT386_EXCEPTION_DF;
|
|
}
|
|
|
|
/* Check if this is a triple fault */
|
|
if (State->ExceptionCount == 3)
|
|
{
|
|
/* Reset the CPU */
|
|
Soft386Reset(State);
|
|
return;
|
|
}
|
|
|
|
if (!Soft386GetIntVector(State, ExceptionCode, &IdtEntry))
|
|
{
|
|
/*
|
|
* If this function failed, that means Soft386Exception
|
|
* was called again, so just return in this case.
|
|
*/
|
|
return;
|
|
}
|
|
|
|
/* Perform the interrupt */
|
|
if (!Soft386InterruptInternal(State,
|
|
IdtEntry.Selector,
|
|
MAKELONG(IdtEntry.Offset, IdtEntry.OffsetHigh),
|
|
IdtEntry.Type))
|
|
{
|
|
/*
|
|
* If this function failed, that means Soft386Exception
|
|
* was called again, so just return in this case.
|
|
*/
|
|
return;
|
|
}
|
|
}
|
|
|
|
inline
|
|
BOOLEAN
|
|
Soft386CalculateParity(UCHAR Number)
|
|
{
|
|
Number ^= Number >> 1;
|
|
Number ^= Number >> 2;
|
|
Number ^= Number >> 4;
|
|
return !(Number & 1);
|
|
}
|
|
|
|
inline
|
|
BOOLEAN
|
|
Soft386ParseModRegRm(PSOFT386_STATE State,
|
|
BOOLEAN AddressSize,
|
|
PSOFT386_MOD_REG_RM ModRegRm)
|
|
{
|
|
UCHAR ModRmByte, Mode, RegMem;
|
|
|
|
/* Fetch the MOD REG R/M byte */
|
|
if (!Soft386FetchByte(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 == SOFT386_REG_ESP)
|
|
{
|
|
UCHAR SibByte;
|
|
ULONG Scale, Index, Base;
|
|
|
|
/* Fetch the SIB byte */
|
|
if (!Soft386FetchByte(State, &SibByte))
|
|
{
|
|
/* Exception occurred */
|
|
return FALSE;
|
|
}
|
|
|
|
/* Unpack the scale, index and base */
|
|
Scale = 1 << (SibByte >> 6);
|
|
Index = (SibByte >> 3) & 0x07;
|
|
if (Index != SOFT386_REG_ESP) Index = State->GeneralRegs[Index].Long;
|
|
else Index = 0;
|
|
Base = State->GeneralRegs[SibByte & 0x07].Long;
|
|
|
|
/* Calculate the address */
|
|
ModRegRm->MemoryAddress = Base + Index * Scale;
|
|
}
|
|
else if (RegMem == SOFT386_REG_EBP)
|
|
{
|
|
if (Mode) ModRegRm->MemoryAddress = State->GeneralRegs[SOFT386_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 & SOFT386_PREFIX_SEG))
|
|
{
|
|
/* Check if the default segment should be SS */
|
|
if ((RegMem == SOFT386_REG_EBP) && Mode)
|
|
{
|
|
/* Add a SS: prefix */
|
|
State->PrefixFlags |= SOFT386_PREFIX_SEG;
|
|
State->SegmentOverride = SOFT386_REG_SS;
|
|
}
|
|
}
|
|
|
|
if (Mode == 1)
|
|
{
|
|
CHAR Offset;
|
|
|
|
/* Fetch the byte */
|
|
if (!Soft386FetchByte(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 == SOFT386_REG_EBP)))
|
|
{
|
|
LONG Offset;
|
|
|
|
/* Fetch the dword */
|
|
if (!Soft386FetchDword(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:
|
|
case 2:
|
|
{
|
|
/* (SS:)[BX + SI] */
|
|
ModRegRm->MemoryAddress = State->GeneralRegs[SOFT386_REG_EBX].LowWord
|
|
+ State->GeneralRegs[SOFT386_REG_ESI].LowWord;
|
|
|
|
break;
|
|
}
|
|
|
|
case 1:
|
|
case 3:
|
|
{
|
|
/* (SS:)[BX + DI] */
|
|
ModRegRm->MemoryAddress = State->GeneralRegs[SOFT386_REG_EBX].LowWord
|
|
+ State->GeneralRegs[SOFT386_REG_EDI].LowWord;
|
|
|
|
break;
|
|
}
|
|
|
|
case 4:
|
|
{
|
|
/* [SI] */
|
|
ModRegRm->MemoryAddress = State->GeneralRegs[SOFT386_REG_ESI].LowWord;
|
|
|
|
break;
|
|
}
|
|
|
|
case 5:
|
|
{
|
|
/* [DI] */
|
|
ModRegRm->MemoryAddress = State->GeneralRegs[SOFT386_REG_EDI].LowWord;
|
|
|
|
break;
|
|
}
|
|
|
|
case 6:
|
|
{
|
|
if (Mode)
|
|
{
|
|
/* [BP] */
|
|
ModRegRm->MemoryAddress = State->GeneralRegs[SOFT386_REG_EBP].LowWord;
|
|
}
|
|
else
|
|
{
|
|
/* [constant] (added later) */
|
|
ModRegRm->MemoryAddress = 0;
|
|
}
|
|
|
|
break;
|
|
}
|
|
|
|
case 7:
|
|
{
|
|
/* [BX] */
|
|
ModRegRm->MemoryAddress = State->GeneralRegs[SOFT386_REG_EBX].LowWord;
|
|
|
|
break;
|
|
}
|
|
}
|
|
|
|
/* Check if there is no segment override */
|
|
if (!(State->PrefixFlags & SOFT386_PREFIX_SEG))
|
|
{
|
|
/* Check if the default segment should be SS */
|
|
if ((RegMem == 2) || (RegMem == 3) || ((RegMem == 6) && Mode))
|
|
{
|
|
/* Add a SS: prefix */
|
|
State->PrefixFlags |= SOFT386_PREFIX_SEG;
|
|
State->SegmentOverride = SOFT386_REG_SS;
|
|
}
|
|
}
|
|
|
|
if (Mode == 1)
|
|
{
|
|
CHAR Offset;
|
|
|
|
/* Fetch the byte */
|
|
if (!Soft386FetchByte(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 (!Soft386FetchWord(State, (PUSHORT)&Offset))
|
|
{
|
|
/* Exception occurred */
|
|
return FALSE;
|
|
}
|
|
|
|
/* Add the signed offset to the address */
|
|
ModRegRm->MemoryAddress += (LONG)Offset;
|
|
}
|
|
}
|
|
|
|
return TRUE;
|
|
}
|
|
|
|
inline
|
|
BOOLEAN
|
|
Soft386ReadModrmByteOperands(PSOFT386_STATE State,
|
|
PSOFT386_MOD_REG_RM ModRegRm,
|
|
PUCHAR RegValue,
|
|
PUCHAR RmValue)
|
|
{
|
|
INT Segment = SOFT386_REG_DS;
|
|
|
|
/* 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 (!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 & SOFT386_PREFIX_SEG)
|
|
{
|
|
/* Use the override segment instead */
|
|
Segment = State->SegmentOverride;
|
|
}
|
|
|
|
/* Read memory */
|
|
if (!Soft386ReadMemory(State,
|
|
Segment,
|
|
ModRegRm->MemoryAddress,
|
|
FALSE,
|
|
RmValue,
|
|
sizeof(UCHAR)))
|
|
{
|
|
/* Exception occurred */
|
|
return FALSE;
|
|
}
|
|
}
|
|
|
|
return TRUE;
|
|
}
|
|
|
|
inline
|
|
BOOLEAN
|
|
Soft386ReadModrmWordOperands(PSOFT386_STATE State,
|
|
PSOFT386_MOD_REG_RM ModRegRm,
|
|
PUSHORT RegValue,
|
|
PUSHORT RmValue)
|
|
{
|
|
INT Segment = SOFT386_REG_DS;
|
|
|
|
/* Get the register value */
|
|
*RegValue = State->GeneralRegs[ModRegRm->Register].LowWord;
|
|
|
|
if (!ModRegRm->Memory)
|
|
{
|
|
/* Get the second register value */
|
|
*RmValue = State->GeneralRegs[ModRegRm->SecondRegister].LowWord;
|
|
}
|
|
else
|
|
{
|
|
/* Check for the segment override */
|
|
if (State->PrefixFlags & SOFT386_PREFIX_SEG)
|
|
{
|
|
/* Use the override segment instead */
|
|
Segment = State->SegmentOverride;
|
|
}
|
|
|
|
/* Read memory */
|
|
if (!Soft386ReadMemory(State,
|
|
Segment,
|
|
ModRegRm->MemoryAddress,
|
|
FALSE,
|
|
RmValue,
|
|
sizeof(USHORT)))
|
|
{
|
|
/* Exception occurred */
|
|
return FALSE;
|
|
}
|
|
}
|
|
|
|
return TRUE;
|
|
}
|
|
|
|
inline
|
|
BOOLEAN
|
|
Soft386ReadModrmDwordOperands(PSOFT386_STATE State,
|
|
PSOFT386_MOD_REG_RM ModRegRm,
|
|
PULONG RegValue,
|
|
PULONG RmValue)
|
|
{
|
|
INT Segment = SOFT386_REG_DS;
|
|
|
|
/* Get the register value */
|
|
*RegValue = State->GeneralRegs[ModRegRm->Register].Long;
|
|
|
|
if (!ModRegRm->Memory)
|
|
{
|
|
/* Get the second register value */
|
|
*RmValue = State->GeneralRegs[ModRegRm->SecondRegister].Long;
|
|
}
|
|
else
|
|
{
|
|
/* Check for the segment override */
|
|
if (State->PrefixFlags & SOFT386_PREFIX_SEG)
|
|
{
|
|
/* Use the override segment instead */
|
|
Segment = State->SegmentOverride;
|
|
}
|
|
|
|
/* Read memory */
|
|
if (!Soft386ReadMemory(State,
|
|
Segment,
|
|
ModRegRm->MemoryAddress,
|
|
FALSE,
|
|
RmValue,
|
|
sizeof(ULONG)))
|
|
{
|
|
/* Exception occurred */
|
|
return FALSE;
|
|
}
|
|
}
|
|
|
|
return TRUE;
|
|
}
|
|
|
|
inline
|
|
BOOLEAN
|
|
Soft386WriteModrmByteOperands(PSOFT386_STATE State,
|
|
PSOFT386_MOD_REG_RM ModRegRm,
|
|
BOOLEAN WriteRegister,
|
|
UCHAR Value)
|
|
{
|
|
INT Segment = SOFT386_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 & SOFT386_PREFIX_SEG)
|
|
{
|
|
/* Use the override segment instead */
|
|
Segment = State->SegmentOverride;
|
|
}
|
|
|
|
/* Write memory */
|
|
if (!Soft386WriteMemory(State,
|
|
Segment,
|
|
ModRegRm->MemoryAddress,
|
|
&Value,
|
|
sizeof(UCHAR)))
|
|
{
|
|
/* Exception occurred */
|
|
return FALSE;
|
|
}
|
|
}
|
|
}
|
|
|
|
return TRUE;
|
|
}
|
|
|
|
inline
|
|
BOOLEAN
|
|
Soft386WriteModrmWordOperands(PSOFT386_STATE State,
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|
PSOFT386_MOD_REG_RM ModRegRm,
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|
BOOLEAN WriteRegister,
|
|
USHORT Value)
|
|
{
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|
INT Segment = SOFT386_REG_DS;
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|
|
|
if (WriteRegister)
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|
{
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|
/* Store the value in the register */
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|
State->GeneralRegs[ModRegRm->Register].LowWord = Value;
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|
}
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|
else
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|
{
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|
if (!ModRegRm->Memory)
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|
{
|
|
/* Store the value in the second register */
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|
State->GeneralRegs[ModRegRm->SecondRegister].LowWord = Value;
|
|
}
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|
else
|
|
{
|
|
/* Check for the segment override */
|
|
if (State->PrefixFlags & SOFT386_PREFIX_SEG)
|
|
{
|
|
/* Use the override segment instead */
|
|
Segment = State->SegmentOverride;
|
|
}
|
|
|
|
/* Write memory */
|
|
if (!Soft386WriteMemory(State,
|
|
Segment,
|
|
ModRegRm->MemoryAddress,
|
|
&Value,
|
|
sizeof(USHORT)))
|
|
{
|
|
/* Exception occurred */
|
|
return FALSE;
|
|
}
|
|
}
|
|
}
|
|
|
|
return TRUE;
|
|
}
|
|
|
|
inline
|
|
BOOLEAN
|
|
Soft386WriteModrnDwordOperands(PSOFT386_STATE State,
|
|
PSOFT386_MOD_REG_RM ModRegRm,
|
|
BOOLEAN WriteRegister,
|
|
ULONG Value)
|
|
{
|
|
INT Segment = SOFT386_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 & SOFT386_PREFIX_SEG)
|
|
{
|
|
/* Use the override segment instead */
|
|
Segment = State->SegmentOverride;
|
|
}
|
|
|
|
/* Write memory */
|
|
if (!Soft386WriteMemory(State,
|
|
Segment,
|
|
ModRegRm->MemoryAddress,
|
|
&Value,
|
|
sizeof(ULONG)))
|
|
{
|
|
/* Exception occurred */
|
|
return FALSE;
|
|
}
|
|
}
|
|
}
|
|
|
|
return TRUE;
|
|
}
|
|
|
|
/* EOF */
|