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 // #define WIN32_NO_STATUS
  25 // #define _INC_WINDOWS
  26 #include <windef.h>
  27
  28 // #define NDEBUG
  29 #include <debug.h>
  30
  31 #include <fast486.h>
  32 #include "common.h"
  33 #include "opcodes.h"
  34
  35 /* DEFINES ********************************************************************/
  36
  37 typedef enum
  38 {
  39     FAST486_STEP_INTO,
  40     FAST486_STEP_OVER,
  41     FAST486_STEP_OUT,
  42     FAST486_CONTINUE
  43 } FAST486_EXEC_CMD;
  44
  45 /* PRIVATE FUNCTIONS **********************************************************/
  46
  47 static
  48 inline
  49 VOID
  50 NTAPI
  51 Fast486ExecutionControl(PFAST486_STATE State, INT Command)
  52 {
  53     UCHAR Opcode;
  54     INT ProcedureCallCount = 0;
  55
  56     /* Main execution loop */
  57     do
  58     {
  59         /* Check if this is a new instruction */
  60         if (State->PrefixFlags == 0)
  61         {
  62             State->SavedInstPtr = State->InstPtr;
  63
  64             /*
  65              * Check if there is an interrupt to execute, or a hardware interrupt signal
  66              * while interrupts are enabled.
  67              */
  68             if ((State->IntStatus == FAST486_INT_EXECUTE)
  69                 || (State->Flags.If
  70                 && (State->IntAckCallback != NULL)
  71                 && (State->IntStatus == FAST486_INT_SIGNAL)))
  72             {
  73                 FAST486_IDT_ENTRY IdtEntry;
  74
  75                 if (State->IntStatus == FAST486_INT_SIGNAL)
  76                 {
  77                     /* Acknowledge the interrupt to get the number */
  78                     State->PendingIntNum = State->IntAckCallback(State);
  79                 }
  80
  81                 /* Get the interrupt vector */
  82                 if (Fast486GetIntVector(State, State->PendingIntNum, &IdtEntry))
  83                 {
  84                     /* Perform the interrupt */
  85                     Fast486InterruptInternal(State,
  86                                              IdtEntry.Selector,
  87                                              MAKELONG(IdtEntry.Offset, IdtEntry.OffsetHigh),
  88                                              IdtEntry.Type);
  89                 }
  90
  91                 /* Clear the interrupt status */
  92                 State->IntStatus = FAST486_INT_NONE;
  93             }
  94         }
  95
  96         /* Perform an instruction fetch */
  97         if (!Fast486FetchByte(State, &Opcode)) continue;
  98
  99         // TODO: Check for CALL/RET to update ProcedureCallCount.
 100
 101         if (Fast486OpcodeHandlers[Opcode] != NULL)
 102         {
 103             /* Call the opcode handler */
 104             Fast486OpcodeHandlers[Opcode](State, Opcode);
 105         }
 106         else
 107         {
 108             /* This is not a valid opcode */
 109             Fast486Exception(State, FAST486_EXCEPTION_UD);
 110         }
 111
 112         if (Fast486OpcodeHandlers[Opcode] != Fast486OpcodePrefix)
 113         {
 114             /* A non-prefix opcode has been executed, reset the prefix flags */
 115             State->PrefixFlags = 0;
 116         }
 117         else
 118         {
 119             /* This is a prefix, go to the next instruction immediately */
 120             continue;
 121         }
 122     }
 123     while ((Command == FAST486_CONTINUE)
 124            || (Command == FAST486_STEP_OVER && ProcedureCallCount > 0)
 125            || (Command == FAST486_STEP_OUT && ProcedureCallCount >= 0)
 126            || (Fast486OpcodeHandlers[Opcode] == Fast486OpcodePrefix));
 127 }
 128
 129 /* PUBLIC FUNCTIONS ***********************************************************/
 130
 131 VOID
 132 NTAPI
 133 Fast486Continue(PFAST486_STATE State)
 134 {
 135     /* Call the internal function */
 136     Fast486ExecutionControl(State, FAST486_CONTINUE);
 137 }
 138
 139 VOID
 140 NTAPI
 141 Fast486StepInto(PFAST486_STATE State)
 142 {
 143     /* Call the internal function */
 144     Fast486ExecutionControl(State, FAST486_STEP_INTO);
 145 }
 146
 147 VOID
 148 NTAPI
 149 Fast486StepOver(PFAST486_STATE State)
 150 {
 151     /* Call the internal function */
 152     Fast486ExecutionControl(State, FAST486_STEP_OVER);
 153 }
 154
 155 VOID
 156 NTAPI
 157 Fast486StepOut(PFAST486_STATE State)
 158 {
 159     /* Call the internal function */
 160     Fast486ExecutionControl(State, FAST486_STEP_OUT);
 161 }
 162
 163 VOID
 164 NTAPI
 165 Fast486DumpState(PFAST486_STATE State)
 166 {
 167     DPRINT1("\nCPU currently executing in %s mode at %04X:%08X\n",
 168             (State->ControlRegisters[0] & FAST486_CR0_PE) ? "protected" : "real",
 169             State->SegmentRegs[FAST486_REG_CS].Selector,
 170             State->InstPtr.Long);
 171     DPRINT1("\nGeneral purpose registers:\n"
 172             "EAX = %08X\tECX = %08X\tEDX = %08X\tEBX = %08X\n"
 173             "ESP = %08X\tEBP = %08X\tESI = %08X\tEDI = %08X\n",
 174             State->GeneralRegs[FAST486_REG_EAX].Long,
 175             State->GeneralRegs[FAST486_REG_ECX].Long,
 176             State->GeneralRegs[FAST486_REG_EDX].Long,
 177             State->GeneralRegs[FAST486_REG_EBX].Long,
 178             State->GeneralRegs[FAST486_REG_ESP].Long,
 179             State->GeneralRegs[FAST486_REG_EBP].Long,
 180             State->GeneralRegs[FAST486_REG_ESI].Long,
 181             State->GeneralRegs[FAST486_REG_EDI].Long);
 182     DPRINT1("\nSegment registers:\n"
 183             "ES = %04X (Base: %08X, Limit: %08X, Dpl: %u)\n"
 184             "CS = %04X (Base: %08X, Limit: %08X, Dpl: %u)\n"
 185             "SS = %04X (Base: %08X, Limit: %08X, Dpl: %u)\n"
 186             "DS = %04X (Base: %08X, Limit: %08X, Dpl: %u)\n"
 187             "FS = %04X (Base: %08X, Limit: %08X, Dpl: %u)\n"
 188             "GS = %04X (Base: %08X, Limit: %08X, Dpl: %u)\n",
 189             State->SegmentRegs[FAST486_REG_ES].Selector,
 190             State->SegmentRegs[FAST486_REG_ES].Base,
 191             State->SegmentRegs[FAST486_REG_ES].Limit,
 192             State->SegmentRegs[FAST486_REG_ES].Dpl,
 193             State->SegmentRegs[FAST486_REG_CS].Selector,
 194             State->SegmentRegs[FAST486_REG_CS].Base,
 195             State->SegmentRegs[FAST486_REG_CS].Limit,
 196             State->SegmentRegs[FAST486_REG_CS].Dpl,
 197             State->SegmentRegs[FAST486_REG_SS].Selector,
 198             State->SegmentRegs[FAST486_REG_SS].Base,
 199             State->SegmentRegs[FAST486_REG_SS].Limit,
 200             State->SegmentRegs[FAST486_REG_SS].Dpl,
 201             State->SegmentRegs[FAST486_REG_DS].Selector,
 202             State->SegmentRegs[FAST486_REG_DS].Base,
 203             State->SegmentRegs[FAST486_REG_DS].Limit,
 204             State->SegmentRegs[FAST486_REG_DS].Dpl,
 205             State->SegmentRegs[FAST486_REG_FS].Selector,
 206             State->SegmentRegs[FAST486_REG_FS].Base,
 207             State->SegmentRegs[FAST486_REG_FS].Limit,
 208             State->SegmentRegs[FAST486_REG_FS].Dpl,
 209             State->SegmentRegs[FAST486_REG_GS].Selector,
 210             State->SegmentRegs[FAST486_REG_GS].Base,
 211             State->SegmentRegs[FAST486_REG_GS].Limit,
 212             State->SegmentRegs[FAST486_REG_GS].Dpl);
 213     DPRINT1("\nFlags: %08X (%s %s %s %s %s %s %s %s %s %s %s %s %s %s %s) Iopl: %u\n",
 214             State->Flags.Long,
 215             State->Flags.Cf ? "CF" : "cf",
 216             State->Flags.Pf ? "PF" : "pf",
 217             State->Flags.Af ? "AF" : "af",
 218             State->Flags.Zf ? "ZF" : "zf",
 219             State->Flags.Sf ? "SF" : "sf",
 220             State->Flags.Tf ? "TF" : "tf",
 221             State->Flags.If ? "IF" : "if",
 222             State->Flags.Df ? "DF" : "df",
 223             State->Flags.Of ? "OF" : "of",
 224             State->Flags.Nt ? "NT" : "nt",
 225             State->Flags.Rf ? "RF" : "rf",
 226             State->Flags.Vm ? "VM" : "vm",
 227             State->Flags.Ac ? "AC" : "ac",
 228             State->Flags.Vif ? "VIF" : "vif",
 229             State->Flags.Vip ? "VIP" : "vip",
 230             State->Flags.Iopl);
 231     DPRINT1("\nControl Registers:\n"
 232             "CR0 = %08X\tCR2 = %08X\tCR3 = %08X\n",
 233             State->ControlRegisters[FAST486_REG_CR0],
 234             State->ControlRegisters[FAST486_REG_CR2],
 235             State->ControlRegisters[FAST486_REG_CR3]);
 236     DPRINT1("\nDebug Registers:\n"
 237             "DR0 = %08X\tDR1 = %08X\tDR2 = %08X\n"
 238             "DR3 = %08X\tDR4 = %08X\tDR5 = %08X\n",
 239             State->DebugRegisters[FAST486_REG_DR0],
 240             State->DebugRegisters[FAST486_REG_DR1],
 241             State->DebugRegisters[FAST486_REG_DR2],
 242             State->DebugRegisters[FAST486_REG_DR3],
 243             State->DebugRegisters[FAST486_REG_DR4],
 244             State->DebugRegisters[FAST486_REG_DR5]);
 245 }
 246
 247 VOID
 248 NTAPI
 249 Fast486Reset(PFAST486_STATE State)
 250 {
 251     INT i;
 252     FAST486_MEM_READ_PROC MemReadCallback = State->MemReadCallback;
 253     FAST486_MEM_WRITE_PROC MemWriteCallback = State->MemWriteCallback;
 254     FAST486_IO_READ_PROC IoReadCallback = State->IoReadCallback;
 255     FAST486_IO_WRITE_PROC IoWriteCallback = State->IoWriteCallback;
 256     FAST486_IDLE_PROC IdleCallback = State->IdleCallback;
 257     FAST486_BOP_PROC BopCallback = State->BopCallback;
 258     FAST486_INT_ACK_PROC IntAckCallback = State->IntAckCallback;
 259
 260     /* Clear the entire structure */
 261     RtlZeroMemory(State, sizeof(*State));
 262
 263     /* Initialize the registers */
 264     State->Flags.AlwaysSet = 1;
 265     State->InstPtr.LowWord = 0xFFF0;
 266
 267     /* Initialize segments */
 268     for (i = 0; i < FAST486_NUM_SEG_REGS; i++)
 269     {
 270         /* Set the selector, base and limit, other values don't apply in real mode */
 271         State->SegmentRegs[i].Selector = 0;
 272         State->SegmentRegs[i].Base = 0;
 273         State->SegmentRegs[i].Limit = 0xFFFF;
 274     }
 275
 276     /* Initialize the code segment */
 277     State->SegmentRegs[FAST486_REG_CS].Selector = 0xF000;
 278     State->SegmentRegs[FAST486_REG_CS].Base = 0xFFFF0000;
 279
 280     /* Initialize the IDT */
 281     State->Idtr.Size = 0x3FF;
 282     State->Idtr.Address = 0;
 283
 284     /* Initialize CR0 */
 285     State->ControlRegisters[FAST486_REG_CR0] |= FAST486_CR0_ET;
 286
 287     /* Restore the callbacks */
 288     State->MemReadCallback = MemReadCallback;
 289     State->MemWriteCallback = MemWriteCallback;
 290     State->IoReadCallback = IoReadCallback;
 291     State->IoWriteCallback = IoWriteCallback;
 292     State->IdleCallback = IdleCallback;
 293     State->BopCallback = BopCallback;
 294     State->IntAckCallback = IntAckCallback;
 295 }
 296
 297 VOID
 298 NTAPI
 299 Fast486Interrupt(PFAST486_STATE State, UCHAR Number)
 300 {
 301     /* Set the interrupt status and the number */
 302     State->IntStatus = FAST486_INT_EXECUTE;
 303     State->PendingIntNum = Number;
 304 }
 305
 306 VOID
 307 NTAPI
 308 Fast486InterruptSignal(PFAST486_STATE State)
 309 {
 310     /* Set the interrupt status */
 311     State->IntStatus = FAST486_INT_SIGNAL;
 312 }
 313
 314 VOID
 315 NTAPI
 316 Fast486ExecuteAt(PFAST486_STATE State, USHORT Segment, ULONG Offset)
 317 {
 318     /* Load the new CS */
 319     if (!Fast486LoadSegment(State, FAST486_REG_CS, Segment))
 320     {
 321         /* An exception occurred, let the handler execute instead */
 322         return;
 323     }
 324
 325     /* Set the new IP */
 326     State->InstPtr.Long = Offset;
 327 }
 328
 329 VOID
 330 NTAPI
 331 Fast486SetStack(PFAST486_STATE State, USHORT Segment, ULONG Offset)
 332 {
 333     /* Load the new SS */
 334     if (!Fast486LoadSegment(State, FAST486_REG_SS, Segment))
 335     {
 336         /* An exception occurred, let the handler execute instead */
 337         return;
 338     }
 339
 340     /* Set the new SP */
 341     State->GeneralRegs[FAST486_REG_ESP].Long = Offset;
 342 }
 343
 344 VOID
 345 NTAPI
 346 Fast486SetSegment(PFAST486_STATE State,
 347                   FAST486_SEG_REGS Segment,
 348                   USHORT Selector)
 349 {
 350     /* Call the internal function */
 351     Fast486LoadSegment(State, Segment, Selector);
 352 }
 353
 354 /* EOF */