reactos/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; // == 0: CPU stopped; >= 1: CPU running or halted
  41
  42 #if 0
  43 LPCWSTR ExceptionName[] =
  44 {
  45     L"Division By Zero",
  46     L"Debug",
  47     L"Unexpected Error",
  48     L"Breakpoint",
  49     L"Integer Overflow",
  50     L"Bound Range Exceeded",
  51     L"Invalid Opcode",
  52     L"FPU Not Available"
  53 };
  54 #endif
  55
  56 // /* BOP Identifiers */
  57 // #define BOP_DEBUGGER    0x56    // Break into the debugger from a 16-bit app
  58
  59 /* PRIVATE FUNCTIONS **********************************************************/
  60
  61 #if 0
  62 VOID EmulatorException(BYTE ExceptionNumber, LPWORD Stack)
  63 {
  64     WORD CodeSegment, InstructionPointer;
  65     PBYTE Opcode;
  66
  67     ASSERT(ExceptionNumber < 8);
  68
  69     /* Get the CS:IP */
  70     InstructionPointer = Stack[STACK_IP];
  71     CodeSegment = Stack[STACK_CS];
  72     Opcode = (PBYTE)SEG_OFF_TO_PTR(CodeSegment, InstructionPointer);
  73
  74     /* Display a message to the user */
  75     DisplayMessage(L"Exception: %s occured at %04X:%04X\n"
  76                    L"Opcode: %02X %02X %02X %02X %02X %02X %02X %02X %02X %02X",
  77                    ExceptionName[ExceptionNumber],
  78                    CodeSegment,
  79                    InstructionPointer,
  80                    Opcode[0],
  81                    Opcode[1],
  82                    Opcode[2],
  83                    Opcode[3],
  84                    Opcode[4],
  85                    Opcode[5],
  86                    Opcode[6],
  87                    Opcode[7],
  88                    Opcode[8],
  89                    Opcode[9]);
  90
  91     /* Stop the VDM */
  92     EmulatorTerminate();
  93     return;
  94 }
  95 #endif
  96
  97 // FIXME: This function assumes 16-bit mode!!!
  98 VOID CpuExecute(WORD Segment, WORD Offset)
  99 {
 100     /* Tell Fast486 to move the instruction pointer */
 101     Fast486ExecuteAt(&EmulatorContext, Segment, Offset);
 102 }
 103
 104 VOID CpuStep(VOID)
 105 {
 106     /* Dump the state for debugging purposes */
 107     // Fast486DumpState(&EmulatorContext);
 108
 109     /* Execute the next instruction */
 110     Fast486StepInto(&EmulatorContext);
 111 }
 112
 113 VOID CpuSimulate(VOID)
 114 {
 115     if (CpuCallLevel > MaxCpuCallLevel)
 116     {
 117         DisplayMessage(L"Too many CPU levels of recursion (%d, expected maximum %d)",
 118                        CpuCallLevel, MaxCpuCallLevel);
 119
 120         /* Stop the VDM */
 121         EmulatorTerminate();
 122         return;
 123     }
 124     CpuCallLevel++;
 125     DPRINT("CpuSimulate --> Level %d\n", CpuCallLevel);
 126
 127     CpuRunning = TRUE;
 128     while (VdmRunning && CpuRunning) ClockUpdate();
 129
 130     DPRINT("CpuSimulate <-- Level %d\n", CpuCallLevel);
 131     CpuCallLevel--;
 132     if (!VdmRunning || CpuCallLevel < 0) CpuCallLevel = 0;
 133
 134     /* This takes into account for reentrance */
 135     if (VdmRunning && (CpuCallLevel > 0)) 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 /* PUBLIC FUNCTIONS ***********************************************************/
 150
 151 BOOLEAN CpuInitialize(VOID)
 152 {
 153     // /* Initialize the internal clock */
 154     // if (!ClockInitialize())
 155     // {
 156         // wprintf(L"FATAL: Failed to initialize the clock\n");
 157         // return FALSE;
 158     // }
 159
 160     /* Initialize the CPU */
 161     Fast486Initialize(&EmulatorContext,
 162                       EmulatorReadMemory,
 163                       EmulatorWriteMemory,
 164                       EmulatorReadIo,
 165                       EmulatorWriteIo,
 166                       NULL,
 167                       EmulatorBiosOperation,
 168                       EmulatorIntAcknowledge,
 169                       NULL /* TODO: Use a TLB */);
 170
 171     /* Initialize the software callback system and register the emulator BOPs */
 172     // RegisterBop(BOP_DEBUGGER  , EmulatorDebugBreakBop);
 173     RegisterBop(BOP_UNSIMULATE, CpuUnsimulateBop);
 174
 175     return TRUE;
 176 }
 177
 178 VOID CpuCleanup(VOID)
 179 {
 180     // Fast486Cleanup();
 181 }
 182
 183 /* EOF */