subsystems/ntvdm/cpu/cpu.c

   1 /*
   2  * COPYRIGHT:       GPL - See COPYING in the top level directory
   3  * PROJECT:         ReactOS Virtual DOS Machine
   4  * FILE:            emulator.c
   5  * PURPOSE:         Minimal x86 machine emulator for the VDM
   6  * PROGRAMMERS:     Aleksandar Andrejevic <theflash AT sdf DOT lonestar DOT org>
   7  */
   8
   9 /* INCLUDES *******************************************************************/
  10
  11 #define NDEBUG
  12
  13 #include "cpu.h"
  14
  15 #include "emulator.h"
  16 #include "callback.h"
  17 #include "bop.h"
  18 #include <isvbop.h>
  19
  20 #include "clock.h"
  21 #include "bios/rom.h"
  22 #include "hardware/cmos.h"
  23 #include "hardware/keyboard.h"
  24 #include "hardware/mouse.h"
  25 #include "hardware/pic.h"
  26 #include "hardware/ps2.h"
  27 #include "hardware/speaker.h"
  28 #include "hardware/timer.h"
  29 #include "hardware/vga.h"
  30
  31 #include "io.h"
  32
  33 /* PRIVATE VARIABLES **********************************************************/
  34
  35 FAST486_STATE EmulatorContext;
  36 BOOLEAN CpuRunning = FALSE;
  37
  38 /* No more than 'MaxCpuCallLevel' recursive CPU calls are allowed */
  39 static const INT MaxCpuCallLevel = 32;
  40 static INT CpuCallLevel = 0;
  41
  42 // BOOLEAN VdmRunning  = TRUE;
  43
  44 #if 0
  45 LPCWSTR ExceptionName[] =
  46 {
  47     L"Division By Zero",
  48     L"Debug",
  49     L"Unexpected Error",
  50     L"Breakpoint",
  51     L"Integer Overflow",
  52     L"Bound Range Exceeded",
  53     L"Invalid Opcode",
  54     L"FPU Not Available"
  55 };
  56 #endif
  57
  58 // /* BOP Identifiers */
  59 // #define BOP_DEBUGGER    0x56    // Break into the debugger from a 16-bit app
  60
  61 /* PRIVATE FUNCTIONS **********************************************************/
  62
  63 #if 0
  64 VOID EmulatorException(BYTE ExceptionNumber, LPWORD Stack)
  65 {
  66     WORD CodeSegment, InstructionPointer;
  67     PBYTE Opcode;
  68
  69     ASSERT(ExceptionNumber < 8);
  70
  71     /* Get the CS:IP */
  72     InstructionPointer = Stack[STACK_IP];
  73     CodeSegment = Stack[STACK_CS];
  74     Opcode = (PBYTE)SEG_OFF_TO_PTR(CodeSegment, InstructionPointer);
  75
  76     /* Display a message to the user */
  77     DisplayMessage(L"Exception: %s occured at %04X:%04X\n"
  78                    L"Opcode: %02X %02X %02X %02X %02X %02X %02X %02X %02X %02X",
  79                    ExceptionName[ExceptionNumber],
  80                    CodeSegment,
  81                    InstructionPointer,
  82                    Opcode[0],
  83                    Opcode[1],
  84                    Opcode[2],
  85                    Opcode[3],
  86                    Opcode[4],
  87                    Opcode[5],
  88                    Opcode[6],
  89                    Opcode[7],
  90                    Opcode[8],
  91                    Opcode[9]);
  92
  93     /* Stop the VDM */
  94     EmulatorTerminate();
  95     return;
  96 }
  97 #endif
  98
  99 // FIXME: This function assumes 16-bit mode!!!
 100 VOID CpuExecute(WORD Segment, WORD Offset)
 101 {
 102     /* Tell Fast486 to move the instruction pointer */
 103     Fast486ExecuteAt(&EmulatorContext, Segment, Offset);
 104 }
 105
 106 VOID CpuStep(VOID)
 107 {
 108     /* Dump the state for debugging purposes */
 109     // Fast486DumpState(&EmulatorContext);
 110
 111     /* Execute the next instruction */
 112     Fast486StepInto(&EmulatorContext);
 113 }
 114
 115 VOID CpuSimulate(VOID)
 116 {
 117     if (CpuCallLevel > MaxCpuCallLevel)
 118     {
 119         DisplayMessage(L"Too many CPU levels of recursion (%d, expected maximum %d)",
 120                        CpuCallLevel, MaxCpuCallLevel);
 121
 122         /* Stop the VDM */
 123         EmulatorTerminate();
 124         return;
 125     }
 126     CpuCallLevel++;
 127
 128     CpuRunning = TRUE;
 129     while (VdmRunning && CpuRunning) ClockUpdate();
 130
 131     CpuCallLevel--;
 132     if (CpuCallLevel < 0) CpuCallLevel = 0;
 133
 134     /* This takes into account for reentrance */
 135     CpuRunning = TRUE;
 136 }
 137
 138 VOID CpuUnsimulate(VOID)
 139 {
 140     /* Stop simulation */
 141     CpuRunning = FALSE;
 142 }
 143
 144 static VOID WINAPI CpuUnsimulateBop(LPWORD Stack)
 145 {
 146     CpuUnsimulate();
 147 }
 148
 149 #if 0
 150 VOID EmulatorTerminate(VOID)
 151 {
 152     /* Stop the VDM */
 153     VdmRunning = FALSE;
 154 }
 155 #endif
 156
 157 /* PUBLIC FUNCTIONS ***********************************************************/
 158
 159 BOOLEAN CpuInitialize(VOID)
 160 {
 161     // /* Initialize the internal clock */
 162     // if (!ClockInitialize())
 163     // {
 164         // wprintf(L"FATAL: Failed to initialize the clock\n");
 165         // return FALSE;
 166     // }
 167
 168     /* Initialize the CPU */
 169     Fast486Initialize(&EmulatorContext,
 170                       EmulatorReadMemory,
 171                       EmulatorWriteMemory,
 172                       EmulatorReadIo,
 173                       EmulatorWriteIo,
 174                       NULL,
 175                       EmulatorBiosOperation,
 176                       EmulatorIntAcknowledge,
 177                       NULL /* TODO: Use a TLB */);
 178
 179     /* Initialize the software callback system and register the emulator BOPs */
 180     // RegisterBop(BOP_DEBUGGER  , EmulatorDebugBreakBop);
 181     RegisterBop(BOP_UNSIMULATE, CpuUnsimulateBop);
 182
 183     return TRUE;
 184 }
 185
 186 VOID CpuCleanup(VOID)
 187 {
 188     // Fast486Cleanup();
 189 }
 190
 191 /* EOF */