lib/fast486/fast486.c

   1 /*
   2  * Fast486 386/486 CPU Emulation Library
   3  * fast486.c
   4  *
   5  * Copyright (C) 2013 Aleksandar Andrejevic <theflash AT sdf DOT lonestar DOT org>
   6  *
   7  * This program is free software; you can redistribute it and/or
   8  * modify it under the terms of the GNU General Public License
   9  * as published by the Free Software Foundation; either version 2
  10  * of the License, or (at your option) any later version.
  11  *
  12  * This program is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15  * GNU General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU General Public License
  18  * along with this program; if not, write to the Free Software
  19  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
  20  */
  21
  22 /* INCLUDES *******************************************************************/
  23
  24 #include <windef.h>
  25
  26 // #define NDEBUG
  27 #include <debug.h>
  28
  29 #include <fast486.h>
  30 #include "common.h"
  31 #include "opcodes.h"
  32
  33 /* DEFINES ********************************************************************/
  34
  35 typedef enum
  36 {
  37     FAST486_STEP_INTO,
  38     FAST486_STEP_OVER,
  39     FAST486_STEP_OUT,
  40     FAST486_CONTINUE
  41 } FAST486_EXEC_CMD;
  42
  43 /* PRIVATE FUNCTIONS **********************************************************/
  44
  45 static
  46 inline
  47 VOID
  48 NTAPI
  49 Fast486ExecutionControl(PFAST486_STATE State, INT Command)
  50 {
  51     UCHAR Opcode;
  52     INT ProcedureCallCount = 0;
  53
  54     /* Main execution loop */
  55     do
  56     {
  57         /* Check if this is a new instruction */
  58         if (State->PrefixFlags == 0)
  59         {
  60             State->SavedInstPtr = State->InstPtr;
  61
  62             /*
  63              * Check if there is an interrupt to execute, or a hardware interrupt signal
  64              * while interrupts are enabled.
  65              */
  66             if ((State->IntStatus == FAST486_INT_EXECUTE)
  67                 || (State->Flags.If
  68                 && (State->IntAckCallback != NULL)
  69                 && (State->IntStatus == FAST486_INT_SIGNAL)))
  70             {
  71                 FAST486_IDT_ENTRY IdtEntry;
  72
  73                 if (State->IntStatus == FAST486_INT_SIGNAL)
  74                 {
  75                     /* Acknowledge the interrupt to get the number */
  76                     State->PendingIntNum = State->IntAckCallback(State);
  77                 }
  78
  79                 /* Get the interrupt vector */
  80                 if (Fast486GetIntVector(State, State->PendingIntNum, &IdtEntry))
  81                 {
  82                     /* Perform the interrupt */
  83                     Fast486InterruptInternal(State,
  84                                              IdtEntry.Selector,
  85                                              MAKELONG(IdtEntry.Offset, IdtEntry.OffsetHigh),
  86                                              IdtEntry.Type);
  87                 }
  88
  89                 /* Clear the interrupt status */
  90                 State->IntStatus = FAST486_INT_NONE;
  91             }
  92         }
  93
  94         /* Perform an instruction fetch */
  95         if (!Fast486FetchByte(State, &Opcode)) continue;
  96
  97         // TODO: Check for CALL/RET to update ProcedureCallCount.
  98
  99         if (Fast486OpcodeHandlers[Opcode] != NULL)
 100         {
 101             /* Call the opcode handler */
 102             Fast486OpcodeHandlers[Opcode](State, Opcode);
 103         }
 104         else
 105         {
 106             /* This is not a valid opcode */
 107             Fast486Exception(State, FAST486_EXCEPTION_UD);
 108         }
 109
 110         if (Fast486OpcodeHandlers[Opcode] != Fast486OpcodePrefix)
 111         {
 112             /* A non-prefix opcode has been executed, reset the prefix flags */
 113             State->PrefixFlags = 0;
 114         }
 115         else
 116         {
 117             /* This is a prefix, go to the next instruction immediately */
 118             continue;
 119         }
 120     }
 121     while ((Command == FAST486_CONTINUE)
 122            || (Command == FAST486_STEP_OVER && ProcedureCallCount > 0)
 123            || (Command == FAST486_STEP_OUT && ProcedureCallCount >= 0)
 124            || (Fast486OpcodeHandlers[Opcode] == Fast486OpcodePrefix));
 125 }
 126
 127 /* DEFAULT CALLBACKS **********************************************************/
 128
 129 static VOID
 130 NTAPI
 131 Fast486MemReadCallback(PFAST486_STATE State, ULONG Address, PVOID Buffer, ULONG Size)
 132 {
 133     UNREFERENCED_PARAMETER(State);
 134
 135     RtlMoveMemory(Buffer, (PVOID)Address, Size);
 136 }
 137
 138 static VOID
 139 NTAPI
 140 Fast486MemWriteCallback(PFAST486_STATE State, ULONG Address, PVOID Buffer, ULONG Size)
 141 {
 142     UNREFERENCED_PARAMETER(State);
 143
 144     RtlMoveMemory((PVOID)Address, Buffer, Size);
 145 }
 146
 147 static VOID
 148 NTAPI
 149 Fast486IoReadCallback(PFAST486_STATE State, ULONG Port, PVOID Buffer, ULONG Size)
 150 {
 151     UNREFERENCED_PARAMETER(State);
 152     UNREFERENCED_PARAMETER(Port);
 153     UNREFERENCED_PARAMETER(Buffer);
 154     UNREFERENCED_PARAMETER(Size);
 155 }
 156
 157 static VOID
 158 NTAPI
 159 Fast486IoWriteCallback(PFAST486_STATE State, ULONG Port, PVOID Buffer, ULONG Size)
 160 {
 161     UNREFERENCED_PARAMETER(State);
 162     UNREFERENCED_PARAMETER(Port);
 163     UNREFERENCED_PARAMETER(Buffer);
 164     UNREFERENCED_PARAMETER(Size);
 165 }
 166
 167 static VOID
 168 NTAPI
 169 Fast486IdleCallback(PFAST486_STATE State)
 170 {
 171     UNREFERENCED_PARAMETER(State);
 172 }
 173
 174 static VOID
 175 NTAPI
 176 Fast486BopCallback(PFAST486_STATE State, UCHAR BopCode)
 177 {
 178     UNREFERENCED_PARAMETER(State);
 179     UNREFERENCED_PARAMETER(BopCode);
 180 }
 181
 182 static UCHAR
 183 NTAPI
 184 Fast486IntAckCallback(PFAST486_STATE State)
 185 {
 186     UNREFERENCED_PARAMETER(State);
 187
 188     /* Return something... */
 189     return 0;
 190 }
 191
 192 /* PUBLIC FUNCTIONS ***********************************************************/
 193
 194 VOID
 195 NTAPI
 196 Fast486Initialize(PFAST486_STATE         State,
 197                   FAST486_MEM_READ_PROC  MemReadCallback,
 198                   FAST486_MEM_WRITE_PROC MemWriteCallback,
 199                   FAST486_IO_READ_PROC   IoReadCallback,
 200                   FAST486_IO_WRITE_PROC  IoWriteCallback,
 201                   FAST486_IDLE_PROC      IdleCallback,
 202                   FAST486_BOP_PROC       BopCallback,
 203                   FAST486_INT_ACK_PROC   IntAckCallback)
 204 {
 205     /* Set the callbacks (or use default ones if some are NULL) */
 206     State->MemReadCallback  = (MemReadCallback  ? MemReadCallback  : Fast486MemReadCallback );
 207     State->MemWriteCallback = (MemWriteCallback ? MemWriteCallback : Fast486MemWriteCallback);
 208     State->IoReadCallback   = (IoReadCallback   ? IoReadCallback   : Fast486IoReadCallback  );
 209     State->IoWriteCallback  = (IoWriteCallback  ? IoWriteCallback  : Fast486IoWriteCallback );
 210     State->IdleCallback     = (IdleCallback     ? IdleCallback     : Fast486IdleCallback    );
 211     State->BopCallback      = (BopCallback      ? BopCallback      : Fast486BopCallback     );
 212     State->IntAckCallback   = (IntAckCallback   ? IntAckCallback   : Fast486IntAckCallback  );
 213
 214     /* Reset the CPU */
 215     Fast486Reset(State);
 216 }
 217
 218 VOID
 219 NTAPI
 220 Fast486Reset(PFAST486_STATE State)
 221 {
 222     USHORT i;
 223
 224     FAST486_MEM_READ_PROC  MemReadCallback  = State->MemReadCallback;
 225     FAST486_MEM_WRITE_PROC MemWriteCallback = State->MemWriteCallback;
 226     FAST486_IO_READ_PROC   IoReadCallback   = State->IoReadCallback;
 227     FAST486_IO_WRITE_PROC  IoWriteCallback  = State->IoWriteCallback;
 228     FAST486_IDLE_PROC      IdleCallback     = State->IdleCallback;
 229     FAST486_BOP_PROC       BopCallback      = State->BopCallback;
 230     FAST486_INT_ACK_PROC   IntAckCallback   = State->IntAckCallback;
 231
 232     /* Clear the entire structure */
 233     RtlZeroMemory(State, sizeof(*State));
 234
 235     /* Initialize the registers */
 236     State->Flags.AlwaysSet = 1;
 237     State->InstPtr.LowWord = 0xFFF0;
 238
 239     /* Initialize segments */
 240     for (i = 0; i < FAST486_NUM_SEG_REGS; i++)
 241     {
 242         /* Set the selector, base and limit, other values don't apply in real mode */
 243         State->SegmentRegs[i].Selector = 0;
 244         State->SegmentRegs[i].Base = 0;
 245         State->SegmentRegs[i].Limit = 0xFFFF;
 246     }
 247
 248     /* Initialize the code segment */
 249     State->SegmentRegs[FAST486_REG_CS].Selector = 0xF000;
 250     State->SegmentRegs[FAST486_REG_CS].Base = 0xFFFF0000;
 251
 252     /* Initialize the IDT */
 253     State->Idtr.Size = 0x3FF;
 254     State->Idtr.Address = 0;
 255
 256     /* Initialize CR0 */
 257     State->ControlRegisters[FAST486_REG_CR0] |= FAST486_CR0_ET;
 258
 259     /* Restore the callbacks */
 260     State->MemReadCallback  = MemReadCallback;
 261     State->MemWriteCallback = MemWriteCallback;
 262     State->IoReadCallback   = IoReadCallback;
 263     State->IoWriteCallback  = IoWriteCallback;
 264     State->IdleCallback     = IdleCallback;
 265     State->BopCallback      = BopCallback;
 266     State->IntAckCallback   = IntAckCallback;
 267 }
 268
 269 VOID
 270 NTAPI
 271 Fast486DumpState(PFAST486_STATE State)
 272 {
 273     DPRINT1("\nCPU currently executing in %s mode at %04X:%08X\n",
 274             (State->ControlRegisters[0] & FAST486_CR0_PE) ? "protected" : "real",
 275             State->SegmentRegs[FAST486_REG_CS].Selector,
 276             State->InstPtr.Long);
 277     DPRINT1("\nGeneral purpose registers:\n"
 278             "EAX = %08X\tECX = %08X\tEDX = %08X\tEBX = %08X\n"
 279             "ESP = %08X\tEBP = %08X\tESI = %08X\tEDI = %08X\n",
 280             State->GeneralRegs[FAST486_REG_EAX].Long,
 281             State->GeneralRegs[FAST486_REG_ECX].Long,
 282             State->GeneralRegs[FAST486_REG_EDX].Long,
 283             State->GeneralRegs[FAST486_REG_EBX].Long,
 284             State->GeneralRegs[FAST486_REG_ESP].Long,
 285             State->GeneralRegs[FAST486_REG_EBP].Long,
 286             State->GeneralRegs[FAST486_REG_ESI].Long,
 287             State->GeneralRegs[FAST486_REG_EDI].Long);
 288     DPRINT1("\nSegment registers:\n"
 289             "ES = %04X (Base: %08X, Limit: %08X, Dpl: %u)\n"
 290             "CS = %04X (Base: %08X, Limit: %08X, Dpl: %u)\n"
 291             "SS = %04X (Base: %08X, Limit: %08X, Dpl: %u)\n"
 292             "DS = %04X (Base: %08X, Limit: %08X, Dpl: %u)\n"
 293             "FS = %04X (Base: %08X, Limit: %08X, Dpl: %u)\n"
 294             "GS = %04X (Base: %08X, Limit: %08X, Dpl: %u)\n",
 295             State->SegmentRegs[FAST486_REG_ES].Selector,
 296             State->SegmentRegs[FAST486_REG_ES].Base,
 297             State->SegmentRegs[FAST486_REG_ES].Limit,
 298             State->SegmentRegs[FAST486_REG_ES].Dpl,
 299             State->SegmentRegs[FAST486_REG_CS].Selector,
 300             State->SegmentRegs[FAST486_REG_CS].Base,
 301             State->SegmentRegs[FAST486_REG_CS].Limit,
 302             State->SegmentRegs[FAST486_REG_CS].Dpl,
 303             State->SegmentRegs[FAST486_REG_SS].Selector,
 304             State->SegmentRegs[FAST486_REG_SS].Base,
 305             State->SegmentRegs[FAST486_REG_SS].Limit,
 306             State->SegmentRegs[FAST486_REG_SS].Dpl,
 307             State->SegmentRegs[FAST486_REG_DS].Selector,
 308             State->SegmentRegs[FAST486_REG_DS].Base,
 309             State->SegmentRegs[FAST486_REG_DS].Limit,
 310             State->SegmentRegs[FAST486_REG_DS].Dpl,
 311             State->SegmentRegs[FAST486_REG_FS].Selector,
 312             State->SegmentRegs[FAST486_REG_FS].Base,
 313             State->SegmentRegs[FAST486_REG_FS].Limit,
 314             State->SegmentRegs[FAST486_REG_FS].Dpl,
 315             State->SegmentRegs[FAST486_REG_GS].Selector,
 316             State->SegmentRegs[FAST486_REG_GS].Base,
 317             State->SegmentRegs[FAST486_REG_GS].Limit,
 318             State->SegmentRegs[FAST486_REG_GS].Dpl);
 319     DPRINT1("\nFlags: %08X (%s %s %s %s %s %s %s %s %s %s %s %s %s %s %s) Iopl: %u\n",
 320             State->Flags.Long,
 321             State->Flags.Cf ? "CF" : "cf",
 322             State->Flags.Pf ? "PF" : "pf",
 323             State->Flags.Af ? "AF" : "af",
 324             State->Flags.Zf ? "ZF" : "zf",
 325             State->Flags.Sf ? "SF" : "sf",
 326             State->Flags.Tf ? "TF" : "tf",
 327             State->Flags.If ? "IF" : "if",
 328             State->Flags.Df ? "DF" : "df",
 329             State->Flags.Of ? "OF" : "of",
 330             State->Flags.Nt ? "NT" : "nt",
 331             State->Flags.Rf ? "RF" : "rf",
 332             State->Flags.Vm ? "VM" : "vm",
 333             State->Flags.Ac ? "AC" : "ac",
 334             State->Flags.Vif ? "VIF" : "vif",
 335             State->Flags.Vip ? "VIP" : "vip",
 336             State->Flags.Iopl);
 337     DPRINT1("\nControl Registers:\n"
 338             "CR0 = %08X\tCR2 = %08X\tCR3 = %08X\n",
 339             State->ControlRegisters[FAST486_REG_CR0],
 340             State->ControlRegisters[FAST486_REG_CR2],
 341             State->ControlRegisters[FAST486_REG_CR3]);
 342     DPRINT1("\nDebug Registers:\n"
 343             "DR0 = %08X\tDR1 = %08X\tDR2 = %08X\n"
 344             "DR3 = %08X\tDR4 = %08X\tDR5 = %08X\n",
 345             State->DebugRegisters[FAST486_REG_DR0],
 346             State->DebugRegisters[FAST486_REG_DR1],
 347             State->DebugRegisters[FAST486_REG_DR2],
 348             State->DebugRegisters[FAST486_REG_DR3],
 349             State->DebugRegisters[FAST486_REG_DR4],
 350             State->DebugRegisters[FAST486_REG_DR5]);
 351 }
 352
 353 VOID
 354 NTAPI
 355 Fast486Continue(PFAST486_STATE State)
 356 {
 357     /* Call the internal function */
 358     Fast486ExecutionControl(State, FAST486_CONTINUE);
 359 }
 360
 361 VOID
 362 NTAPI
 363 Fast486StepInto(PFAST486_STATE State)
 364 {
 365     /* Call the internal function */
 366     Fast486ExecutionControl(State, FAST486_STEP_INTO);
 367 }
 368
 369 VOID
 370 NTAPI
 371 Fast486StepOver(PFAST486_STATE State)
 372 {
 373     /* Call the internal function */
 374     Fast486ExecutionControl(State, FAST486_STEP_OVER);
 375 }
 376
 377 VOID
 378 NTAPI
 379 Fast486StepOut(PFAST486_STATE State)
 380 {
 381     /* Call the internal function */
 382     Fast486ExecutionControl(State, FAST486_STEP_OUT);
 383 }
 384
 385 VOID
 386 NTAPI
 387 Fast486Interrupt(PFAST486_STATE State, UCHAR Number)
 388 {
 389     /* Set the interrupt status and the number */
 390     State->IntStatus = FAST486_INT_EXECUTE;
 391     State->PendingIntNum = Number;
 392 }
 393
 394 VOID
 395 NTAPI
 396 Fast486InterruptSignal(PFAST486_STATE State)
 397 {
 398     /* Set the interrupt status */
 399     State->IntStatus = FAST486_INT_SIGNAL;
 400 }
 401
 402 VOID
 403 NTAPI
 404 Fast486ExecuteAt(PFAST486_STATE State, USHORT Segment, ULONG Offset)
 405 {
 406     /* Load the new CS */
 407     if (!Fast486LoadSegment(State, FAST486_REG_CS, Segment))
 408     {
 409         /* An exception occurred, let the handler execute instead */
 410         return;
 411     }
 412
 413     /* Set the new IP */
 414     State->InstPtr.Long = Offset;
 415 }
 416
 417 VOID
 418 NTAPI
 419 Fast486SetStack(PFAST486_STATE State, USHORT Segment, ULONG Offset)
 420 {
 421     /* Load the new SS */
 422     if (!Fast486LoadSegment(State, FAST486_REG_SS, Segment))
 423     {
 424         /* An exception occurred, let the handler execute instead */
 425         return;
 426     }
 427
 428     /* Set the new SP */
 429     State->GeneralRegs[FAST486_REG_ESP].Long = Offset;
 430 }
 431
 432 VOID
 433 NTAPI
 434 Fast486SetSegment(PFAST486_STATE State,
 435                   FAST486_SEG_REGS Segment,
 436                   USHORT Selector)
 437 {
 438     /* Call the internal function */
 439     Fast486LoadSegment(State, Segment, Selector);
 440 }
 441
 442 /* EOF */