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 /* PUBLIC FUNCTIONS ***********************************************************/
 128
 129 VOID
 130 NTAPI
 131 Fast486Continue(PFAST486_STATE State)
 132 {
 133     /* Call the internal function */
 134     Fast486ExecutionControl(State, FAST486_CONTINUE);
 135 }
 136
 137 VOID
 138 NTAPI
 139 Fast486StepInto(PFAST486_STATE State)
 140 {
 141     /* Call the internal function */
 142     Fast486ExecutionControl(State, FAST486_STEP_INTO);
 143 }
 144
 145 VOID
 146 NTAPI
 147 Fast486StepOver(PFAST486_STATE State)
 148 {
 149     /* Call the internal function */
 150     Fast486ExecutionControl(State, FAST486_STEP_OVER);
 151 }
 152
 153 VOID
 154 NTAPI
 155 Fast486StepOut(PFAST486_STATE State)
 156 {
 157     /* Call the internal function */
 158     Fast486ExecutionControl(State, FAST486_STEP_OUT);
 159 }
 160
 161 VOID
 162 NTAPI
 163 Fast486DumpState(PFAST486_STATE State)
 164 {
 165     DPRINT1("\nCPU currently executing in %s mode at %04X:%08X\n",
 166             (State->ControlRegisters[0] & FAST486_CR0_PE) ? "protected" : "real",
 167             State->SegmentRegs[FAST486_REG_CS].Selector,
 168             State->InstPtr.Long);
 169     DPRINT1("\nGeneral purpose registers:\n"
 170             "EAX = %08X\tECX = %08X\tEDX = %08X\tEBX = %08X\n"
 171             "ESP = %08X\tEBP = %08X\tESI = %08X\tEDI = %08X\n",
 172             State->GeneralRegs[FAST486_REG_EAX].Long,
 173             State->GeneralRegs[FAST486_REG_ECX].Long,
 174             State->GeneralRegs[FAST486_REG_EDX].Long,
 175             State->GeneralRegs[FAST486_REG_EBX].Long,
 176             State->GeneralRegs[FAST486_REG_ESP].Long,
 177             State->GeneralRegs[FAST486_REG_EBP].Long,
 178             State->GeneralRegs[FAST486_REG_ESI].Long,
 179             State->GeneralRegs[FAST486_REG_EDI].Long);
 180     DPRINT1("\nSegment registers:\n"
 181             "ES = %04X (Base: %08X, Limit: %08X, Dpl: %u)\n"
 182             "CS = %04X (Base: %08X, Limit: %08X, Dpl: %u)\n"
 183             "SS = %04X (Base: %08X, Limit: %08X, Dpl: %u)\n"
 184             "DS = %04X (Base: %08X, Limit: %08X, Dpl: %u)\n"
 185             "FS = %04X (Base: %08X, Limit: %08X, Dpl: %u)\n"
 186             "GS = %04X (Base: %08X, Limit: %08X, Dpl: %u)\n",
 187             State->SegmentRegs[FAST486_REG_ES].Selector,
 188             State->SegmentRegs[FAST486_REG_ES].Base,
 189             State->SegmentRegs[FAST486_REG_ES].Limit,
 190             State->SegmentRegs[FAST486_REG_ES].Dpl,
 191             State->SegmentRegs[FAST486_REG_CS].Selector,
 192             State->SegmentRegs[FAST486_REG_CS].Base,
 193             State->SegmentRegs[FAST486_REG_CS].Limit,
 194             State->SegmentRegs[FAST486_REG_CS].Dpl,
 195             State->SegmentRegs[FAST486_REG_SS].Selector,
 196             State->SegmentRegs[FAST486_REG_SS].Base,
 197             State->SegmentRegs[FAST486_REG_SS].Limit,
 198             State->SegmentRegs[FAST486_REG_SS].Dpl,
 199             State->SegmentRegs[FAST486_REG_DS].Selector,
 200             State->SegmentRegs[FAST486_REG_DS].Base,
 201             State->SegmentRegs[FAST486_REG_DS].Limit,
 202             State->SegmentRegs[FAST486_REG_DS].Dpl,
 203             State->SegmentRegs[FAST486_REG_FS].Selector,
 204             State->SegmentRegs[FAST486_REG_FS].Base,
 205             State->SegmentRegs[FAST486_REG_FS].Limit,
 206             State->SegmentRegs[FAST486_REG_FS].Dpl,
 207             State->SegmentRegs[FAST486_REG_GS].Selector,
 208             State->SegmentRegs[FAST486_REG_GS].Base,
 209             State->SegmentRegs[FAST486_REG_GS].Limit,
 210             State->SegmentRegs[FAST486_REG_GS].Dpl);
 211     DPRINT1("\nFlags: %08X (%s %s %s %s %s %s %s %s %s %s %s %s %s %s %s) Iopl: %u\n",
 212             State->Flags.Long,
 213             State->Flags.Cf ? "CF" : "cf",
 214             State->Flags.Pf ? "PF" : "pf",
 215             State->Flags.Af ? "AF" : "af",
 216             State->Flags.Zf ? "ZF" : "zf",
 217             State->Flags.Sf ? "SF" : "sf",
 218             State->Flags.Tf ? "TF" : "tf",
 219             State->Flags.If ? "IF" : "if",
 220             State->Flags.Df ? "DF" : "df",
 221             State->Flags.Of ? "OF" : "of",
 222             State->Flags.Nt ? "NT" : "nt",
 223             State->Flags.Rf ? "RF" : "rf",
 224             State->Flags.Vm ? "VM" : "vm",
 225             State->Flags.Ac ? "AC" : "ac",
 226             State->Flags.Vif ? "VIF" : "vif",
 227             State->Flags.Vip ? "VIP" : "vip",
 228             State->Flags.Iopl);
 229     DPRINT1("\nControl Registers:\n"
 230             "CR0 = %08X\tCR2 = %08X\tCR3 = %08X\n",
 231             State->ControlRegisters[FAST486_REG_CR0],
 232             State->ControlRegisters[FAST486_REG_CR2],
 233             State->ControlRegisters[FAST486_REG_CR3]);
 234     DPRINT1("\nDebug Registers:\n"
 235             "DR0 = %08X\tDR1 = %08X\tDR2 = %08X\n"
 236             "DR3 = %08X\tDR4 = %08X\tDR5 = %08X\n",
 237             State->DebugRegisters[FAST486_REG_DR0],
 238             State->DebugRegisters[FAST486_REG_DR1],
 239             State->DebugRegisters[FAST486_REG_DR2],
 240             State->DebugRegisters[FAST486_REG_DR3],
 241             State->DebugRegisters[FAST486_REG_DR4],
 242             State->DebugRegisters[FAST486_REG_DR5]);
 243 }
 244
 245 VOID
 246 NTAPI
 247 Fast486Reset(PFAST486_STATE State)
 248 {
 249     INT i;
 250     FAST486_MEM_READ_PROC MemReadCallback = State->MemReadCallback;
 251     FAST486_MEM_WRITE_PROC MemWriteCallback = State->MemWriteCallback;
 252     FAST486_IO_READ_PROC IoReadCallback = State->IoReadCallback;
 253     FAST486_IO_WRITE_PROC IoWriteCallback = State->IoWriteCallback;
 254     FAST486_IDLE_PROC IdleCallback = State->IdleCallback;
 255     FAST486_BOP_PROC BopCallback = State->BopCallback;
 256     FAST486_INT_ACK_PROC IntAckCallback = State->IntAckCallback;
 257
 258     /* Clear the entire structure */
 259     RtlZeroMemory(State, sizeof(*State));
 260
 261     /* Initialize the registers */
 262     State->Flags.AlwaysSet = 1;
 263     State->InstPtr.LowWord = 0xFFF0;
 264
 265     /* Initialize segments */
 266     for (i = 0; i < FAST486_NUM_SEG_REGS; i++)
 267     {
 268         /* Set the selector, base and limit, other values don't apply in real mode */
 269         State->SegmentRegs[i].Selector = 0;
 270         State->SegmentRegs[i].Base = 0;
 271         State->SegmentRegs[i].Limit = 0xFFFF;
 272     }
 273
 274     /* Initialize the code segment */
 275     State->SegmentRegs[FAST486_REG_CS].Selector = 0xF000;
 276     State->SegmentRegs[FAST486_REG_CS].Base = 0xFFFF0000;
 277
 278     /* Initialize the IDT */
 279     State->Idtr.Size = 0x3FF;
 280     State->Idtr.Address = 0;
 281
 282     /* Initialize CR0 */
 283     State->ControlRegisters[FAST486_REG_CR0] |= FAST486_CR0_ET;
 284
 285     /* Restore the callbacks */
 286     State->MemReadCallback = MemReadCallback;
 287     State->MemWriteCallback = MemWriteCallback;
 288     State->IoReadCallback = IoReadCallback;
 289     State->IoWriteCallback = IoWriteCallback;
 290     State->IdleCallback = IdleCallback;
 291     State->BopCallback = BopCallback;
 292     State->IntAckCallback = IntAckCallback;
 293 }
 294
 295 VOID
 296 NTAPI
 297 Fast486Interrupt(PFAST486_STATE State, UCHAR Number)
 298 {
 299     /* Set the interrupt status and the number */
 300     State->IntStatus = FAST486_INT_EXECUTE;
 301     State->PendingIntNum = Number;
 302 }
 303
 304 VOID
 305 NTAPI
 306 Fast486InterruptSignal(PFAST486_STATE State)
 307 {
 308     /* Set the interrupt status */
 309     State->IntStatus = FAST486_INT_SIGNAL;
 310 }
 311
 312 VOID
 313 NTAPI
 314 Fast486ExecuteAt(PFAST486_STATE State, USHORT Segment, ULONG Offset)
 315 {
 316     /* Load the new CS */
 317     if (!Fast486LoadSegment(State, FAST486_REG_CS, Segment))
 318     {
 319         /* An exception occurred, let the handler execute instead */
 320         return;
 321     }
 322
 323     /* Set the new IP */
 324     State->InstPtr.Long = Offset;
 325 }
 326
 327 VOID
 328 NTAPI
 329 Fast486SetStack(PFAST486_STATE State, USHORT Segment, ULONG Offset)
 330 {
 331     /* Load the new SS */
 332     if (!Fast486LoadSegment(State, FAST486_REG_SS, Segment))
 333     {
 334         /* An exception occurred, let the handler execute instead */
 335         return;
 336     }
 337
 338     /* Set the new SP */
 339     State->GeneralRegs[FAST486_REG_ESP].Long = Offset;
 340 }
 341
 342 VOID
 343 NTAPI
 344 Fast486SetSegment(PFAST486_STATE State,
 345                   FAST486_SEG_REGS Segment,
 346                   USHORT Selector)
 347 {
 348     /* Call the internal function */
 349     Fast486LoadSegment(State, Segment, Selector);
 350 }
 351
 352 /* EOF */