mirror of
https://github.com/reactos/reactos.git
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183 lines
4.6 KiB
C
183 lines
4.6 KiB
C
/*
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* COPYRIGHT: GPL - See COPYING in the top level directory
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* PROJECT: ReactOS Virtual DOS Machine
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* FILE: emulator.c
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* PURPOSE: Minimal x86 machine emulator for the VDM
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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 NDEBUG
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#include "cpu.h"
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#include "emulator.h"
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#include "callback.h"
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#include "bop.h"
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#include <isvbop.h>
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#include "clock.h"
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#include "bios/rom.h"
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#include "hardware/cmos.h"
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#include "hardware/keyboard.h"
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#include "hardware/mouse.h"
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#include "hardware/pic.h"
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#include "hardware/ps2.h"
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#include "hardware/speaker.h"
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#include "hardware/timer.h"
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#include "hardware/vga.h"
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#include "io.h"
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/* PRIVATE VARIABLES **********************************************************/
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FAST486_STATE EmulatorContext;
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BOOLEAN CpuRunning = FALSE;
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/* No more than 'MaxCpuCallLevel' recursive CPU calls are allowed */
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static const INT MaxCpuCallLevel = 32;
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static INT CpuCallLevel = 0; // == 0: CPU stopped; >= 1: CPU running or halted
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#if 0
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LPCWSTR ExceptionName[] =
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{
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L"Division By Zero",
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L"Debug",
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L"Unexpected Error",
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L"Breakpoint",
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L"Integer Overflow",
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L"Bound Range Exceeded",
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L"Invalid Opcode",
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L"FPU Not Available"
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};
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#endif
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// /* BOP Identifiers */
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// #define BOP_DEBUGGER 0x56 // Break into the debugger from a 16-bit app
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/* PRIVATE FUNCTIONS **********************************************************/
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#if 0
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VOID EmulatorException(BYTE ExceptionNumber, LPWORD Stack)
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{
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WORD CodeSegment, InstructionPointer;
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PBYTE Opcode;
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ASSERT(ExceptionNumber < 8);
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/* Get the CS:IP */
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InstructionPointer = Stack[STACK_IP];
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CodeSegment = Stack[STACK_CS];
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Opcode = (PBYTE)SEG_OFF_TO_PTR(CodeSegment, InstructionPointer);
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/* Display a message to the user */
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DisplayMessage(L"Exception: %s occured at %04X:%04X\n"
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L"Opcode: %02X %02X %02X %02X %02X %02X %02X %02X %02X %02X",
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ExceptionName[ExceptionNumber],
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CodeSegment,
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InstructionPointer,
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Opcode[0],
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Opcode[1],
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Opcode[2],
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Opcode[3],
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Opcode[4],
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Opcode[5],
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Opcode[6],
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Opcode[7],
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Opcode[8],
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Opcode[9]);
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/* Stop the VDM */
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EmulatorTerminate();
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return;
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}
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#endif
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// FIXME: This function assumes 16-bit mode!!!
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VOID CpuExecute(WORD Segment, WORD Offset)
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{
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/* Tell Fast486 to move the instruction pointer */
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Fast486ExecuteAt(&EmulatorContext, Segment, Offset);
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}
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VOID CpuStep(VOID)
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{
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/* Dump the state for debugging purposes */
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// Fast486DumpState(&EmulatorContext);
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/* Execute the next instruction */
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Fast486StepInto(&EmulatorContext);
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}
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VOID CpuSimulate(VOID)
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{
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if (CpuCallLevel > MaxCpuCallLevel)
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{
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DisplayMessage(L"Too many CPU levels of recursion (%d, expected maximum %d)",
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CpuCallLevel, MaxCpuCallLevel);
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/* Stop the VDM */
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EmulatorTerminate();
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return;
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}
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CpuCallLevel++;
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DPRINT("CpuSimulate --> Level %d\n", CpuCallLevel);
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CpuRunning = TRUE;
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while (VdmRunning && CpuRunning) ClockUpdate();
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DPRINT("CpuSimulate <-- Level %d\n", CpuCallLevel);
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CpuCallLevel--;
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if (!VdmRunning || CpuCallLevel < 0) CpuCallLevel = 0;
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/* This takes into account for reentrance */
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if (VdmRunning && (CpuCallLevel > 0)) CpuRunning = TRUE;
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}
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VOID CpuUnsimulate(VOID)
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{
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/* Stop simulation */
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CpuRunning = FALSE;
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}
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static VOID WINAPI CpuUnsimulateBop(LPWORD Stack)
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{
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CpuUnsimulate();
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}
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/* PUBLIC FUNCTIONS ***********************************************************/
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BOOLEAN CpuInitialize(VOID)
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{
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// /* Initialize the internal clock */
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// if (!ClockInitialize())
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// {
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// wprintf(L"FATAL: Failed to initialize the clock\n");
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// return FALSE;
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// }
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/* Initialize the CPU */
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Fast486Initialize(&EmulatorContext,
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EmulatorReadMemory,
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EmulatorWriteMemory,
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EmulatorReadIo,
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EmulatorWriteIo,
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EmulatorBiosOperation,
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EmulatorIntAcknowledge,
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NULL /* TODO: Use a TLB */);
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/* Initialize the software callback system and register the emulator BOPs */
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// RegisterBop(BOP_DEBUGGER , EmulatorDebugBreakBop);
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RegisterBop(BOP_UNSIMULATE, CpuUnsimulateBop);
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return TRUE;
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}
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VOID CpuCleanup(VOID)
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{
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// Fast486Cleanup();
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}
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/* EOF */
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