mirror of
https://github.com/reactos/reactos.git
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264 lines
7.7 KiB
C
264 lines
7.7 KiB
C
/*
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* Fast486 386/486 CPU Emulation Library
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* fast486.c
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*
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* Copyright (C) 2015 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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/* INCLUDES *******************************************************************/
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#include <windef.h>
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// #define NDEBUG
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#include <debug.h>
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#include <fast486.h>
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#include "common.h"
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#include "opcodes.h"
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#include "fpu.h"
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/* DEFAULT CALLBACKS **********************************************************/
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static VOID
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FASTCALL
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Fast486MemReadCallback(PFAST486_STATE State, ULONG Address, PVOID Buffer, ULONG Size)
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{
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UNREFERENCED_PARAMETER(State);
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RtlMoveMemory(Buffer, (PVOID)Address, Size);
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}
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static VOID
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FASTCALL
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Fast486MemWriteCallback(PFAST486_STATE State, ULONG Address, PVOID Buffer, ULONG Size)
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{
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UNREFERENCED_PARAMETER(State);
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RtlMoveMemory((PVOID)Address, Buffer, Size);
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}
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static VOID
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FASTCALL
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Fast486IoReadCallback(PFAST486_STATE State, USHORT Port, PVOID Buffer, ULONG DataCount, UCHAR DataSize)
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{
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UNREFERENCED_PARAMETER(State);
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UNREFERENCED_PARAMETER(Port);
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UNREFERENCED_PARAMETER(Buffer);
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UNREFERENCED_PARAMETER(DataCount);
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UNREFERENCED_PARAMETER(DataSize);
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}
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static VOID
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FASTCALL
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Fast486IoWriteCallback(PFAST486_STATE State, USHORT Port, PVOID Buffer, ULONG DataCount, UCHAR DataSize)
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{
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UNREFERENCED_PARAMETER(State);
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UNREFERENCED_PARAMETER(Port);
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UNREFERENCED_PARAMETER(Buffer);
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UNREFERENCED_PARAMETER(DataCount);
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UNREFERENCED_PARAMETER(DataSize);
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}
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static VOID
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FASTCALL
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Fast486BopCallback(PFAST486_STATE State, UCHAR BopCode)
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{
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UNREFERENCED_PARAMETER(State);
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UNREFERENCED_PARAMETER(BopCode);
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}
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static UCHAR
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FASTCALL
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Fast486IntAckCallback(PFAST486_STATE State)
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{
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UNREFERENCED_PARAMETER(State);
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/* Return something... defaulted to single-step interrupt */
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return 0x01;
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}
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static VOID
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FASTCALL
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Fast486FpuCallback(PFAST486_STATE State)
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{
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UNREFERENCED_PARAMETER(State);
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}
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/* PUBLIC FUNCTIONS ***********************************************************/
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VOID
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NTAPI
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Fast486Initialize(PFAST486_STATE State,
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FAST486_MEM_READ_PROC MemReadCallback,
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FAST486_MEM_WRITE_PROC MemWriteCallback,
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FAST486_IO_READ_PROC IoReadCallback,
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FAST486_IO_WRITE_PROC IoWriteCallback,
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FAST486_BOP_PROC BopCallback,
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FAST486_INT_ACK_PROC IntAckCallback,
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FAST486_FPU_PROC FpuCallback,
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PULONG Tlb)
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{
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/* Set the callbacks (or use default ones if some are NULL) */
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State->MemReadCallback = (MemReadCallback ? MemReadCallback : Fast486MemReadCallback );
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State->MemWriteCallback = (MemWriteCallback ? MemWriteCallback : Fast486MemWriteCallback);
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State->IoReadCallback = (IoReadCallback ? IoReadCallback : Fast486IoReadCallback );
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State->IoWriteCallback = (IoWriteCallback ? IoWriteCallback : Fast486IoWriteCallback );
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State->BopCallback = (BopCallback ? BopCallback : Fast486BopCallback );
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State->IntAckCallback = (IntAckCallback ? IntAckCallback : Fast486IntAckCallback );
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State->FpuCallback = (FpuCallback ? FpuCallback : Fast486FpuCallback );
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/* Set the TLB (if given) */
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State->Tlb = Tlb;
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/* Reset the CPU */
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Fast486Reset(State);
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}
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VOID
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NTAPI
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Fast486Reset(PFAST486_STATE State)
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{
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FAST486_SEG_REGS i;
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/* Save the callbacks and TLB */
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FAST486_MEM_READ_PROC MemReadCallback = State->MemReadCallback;
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FAST486_MEM_WRITE_PROC MemWriteCallback = State->MemWriteCallback;
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FAST486_IO_READ_PROC IoReadCallback = State->IoReadCallback;
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FAST486_IO_WRITE_PROC IoWriteCallback = State->IoWriteCallback;
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FAST486_BOP_PROC BopCallback = State->BopCallback;
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FAST486_INT_ACK_PROC IntAckCallback = State->IntAckCallback;
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FAST486_FPU_PROC FpuCallback = State->FpuCallback;
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PULONG Tlb = State->Tlb;
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/* Clear the entire structure */
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RtlZeroMemory(State, sizeof(*State));
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/* Initialize the registers */
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State->Flags.AlwaysSet = 1;
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State->InstPtr.LowWord = 0xFFF0;
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/* Set the CPL to 0 */
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State->Cpl = 0;
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/* Initialize segments */
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for (i = 0; i < FAST486_NUM_SEG_REGS; i++)
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{
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State->SegmentRegs[i].Selector = 0;
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State->SegmentRegs[i].Base = 0;
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State->SegmentRegs[i].Limit = 0xFFFF;
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State->SegmentRegs[i].Present = TRUE;
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State->SegmentRegs[i].ReadWrite = TRUE;
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State->SegmentRegs[i].Executable = FALSE;
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State->SegmentRegs[i].DirConf = FALSE;
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State->SegmentRegs[i].SystemType = 1; // Segment descriptor
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State->SegmentRegs[i].Dpl = 0;
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State->SegmentRegs[i].Size = FALSE; // 16-bit
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}
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/* Initialize the code segment */
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State->SegmentRegs[FAST486_REG_CS].Executable = TRUE;
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State->SegmentRegs[FAST486_REG_CS].Selector = 0xF000;
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State->SegmentRegs[FAST486_REG_CS].Base = 0xFFFF0000;
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/* Initialize the IDT */
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State->Idtr.Size = 0x3FF;
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State->Idtr.Address = 0;
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#ifndef FAST486_NO_FPU
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/* Initialize CR0 */
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State->ControlRegisters[FAST486_REG_CR0] |= FAST486_CR0_ET;
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/* Initialize the FPU control and tag registers */
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State->FpuControl.Value = FAST486_FPU_DEFAULT_CONTROL;
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State->FpuStatus.Value = 0;
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State->FpuTag = 0xFFFF;
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#endif
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/* Restore the callbacks and TLB */
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State->MemReadCallback = MemReadCallback;
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State->MemWriteCallback = MemWriteCallback;
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State->IoReadCallback = IoReadCallback;
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State->IoWriteCallback = IoWriteCallback;
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State->BopCallback = BopCallback;
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State->IntAckCallback = IntAckCallback;
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State->FpuCallback = FpuCallback;
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State->Tlb = Tlb;
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/* Flush the TLB */
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Fast486FlushTlb(State);
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}
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VOID
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NTAPI
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Fast486InterruptSignal(PFAST486_STATE State)
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{
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State->IntSignaled = TRUE;
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}
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VOID
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NTAPI
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Fast486ExecuteAt(PFAST486_STATE State, USHORT Segment, ULONG Offset)
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{
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/* Load the new CS */
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if (!Fast486LoadSegment(State, FAST486_REG_CS, Segment))
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{
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/* An exception occurred, let the handler execute instead */
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return;
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}
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/* Set the new IP */
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State->InstPtr.Long = Offset;
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}
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VOID
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NTAPI
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Fast486SetStack(PFAST486_STATE State, USHORT Segment, ULONG Offset)
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{
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/* Load the new SS */
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if (!Fast486LoadSegment(State, FAST486_REG_SS, Segment))
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{
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/* An exception occurred, let the handler execute instead */
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return;
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}
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/* Set the new SP */
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State->GeneralRegs[FAST486_REG_ESP].Long = Offset;
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}
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VOID
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NTAPI
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Fast486SetSegment(PFAST486_STATE State,
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FAST486_SEG_REGS Segment,
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USHORT Selector)
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{
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/* Call the internal function */
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Fast486LoadSegment(State, Segment, Selector);
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}
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VOID
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NTAPI
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Fast486Rewind(PFAST486_STATE State)
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{
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/* This function is used when an instruction has been interrupted remotely */
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State->PrefixFlags = 0;
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State->InstPtr.Long = State->SavedInstPtr.Long;
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#ifndef FAST486_NO_PREFETCH
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State->PrefetchValid = FALSE;
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#endif
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}
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/* EOF */
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