lib/soft386/soft386.c

   1 /*
   2  * Soft386 386/486 CPU Emulation Library
   3  * soft386.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 <soft386.h>
  32 #include "common.h"
  33 #include "opcodes.h"
  34
  35 /* DEFINES ********************************************************************/
  36
  37 typedef enum
  38 {
  39     SOFT386_STEP_INTO,
  40     SOFT386_STEP_OVER,
  41     SOFT386_STEP_OUT,
  42     SOFT386_CONTINUE
  43 } SOFT386_EXEC_CMD;
  44
  45 /* PRIVATE FUNCTIONS **********************************************************/
  46
  47 static
  48 inline
  49 VOID
  50 NTAPI
  51 Soft386ExecutionControl(PSOFT386_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             /* Check if interrupts are enabled and there is an interrupt pending */
  65             if (State->Flags.If && State->HardwareInt)
  66             {
  67                 SOFT386_IDT_ENTRY IdtEntry;
  68
  69                 /* Get the interrupt vector */
  70                 if (Soft386GetIntVector(State, State->PendingIntNum, &IdtEntry))
  71                 {
  72                     /* Perform the interrupt */
  73                     Soft386InterruptInternal(State,
  74                                              IdtEntry.Selector,
  75                                              MAKELONG(IdtEntry.Offset, IdtEntry.OffsetHigh),
  76                                              IdtEntry.Type);
  77                 }
  78
  79                 /* Clear the interrupt pending flag */
  80                 State->HardwareInt = FALSE;
  81             }
  82         }
  83
  84         /* Perform an instruction fetch */
  85         if (!Soft386FetchByte(State, &Opcode)) continue;
  86
  87         // TODO: Check for CALL/RET to update ProcedureCallCount.
  88
  89         if (Soft386OpcodeHandlers[Opcode] != NULL)
  90         {
  91             /* Call the opcode handler */
  92             Soft386OpcodeHandlers[Opcode](State, Opcode);
  93         }
  94         else
  95         {
  96             /* This is not a valid opcode */
  97             Soft386Exception(State, SOFT386_EXCEPTION_UD);
  98         }
  99
 100         if (Soft386OpcodeHandlers[Opcode] != Soft386OpcodePrefix)
 101         {
 102             /* A non-prefix opcode has been executed, reset the prefix flags */
 103             State->PrefixFlags = 0;
 104         }
 105         else
 106         {
 107             /* This is a prefix, go to the next instruction immediately */
 108             continue;
 109         }
 110
 111         /* Increment the time stamp counter */
 112         State->TimeStampCounter++;
 113     }
 114     while ((Command == SOFT386_CONTINUE)
 115            || (Command == SOFT386_STEP_OVER && ProcedureCallCount > 0)
 116            || (Command == SOFT386_STEP_OUT && ProcedureCallCount >= 0)
 117            || (Soft386OpcodeHandlers[Opcode] == Soft386OpcodePrefix));
 118 }
 119
 120 /* PUBLIC FUNCTIONS ***********************************************************/
 121
 122 VOID
 123 NTAPI
 124 Soft386Continue(PSOFT386_STATE State)
 125 {
 126     /* Call the internal function */
 127     Soft386ExecutionControl(State, SOFT386_CONTINUE);
 128 }
 129
 130 VOID
 131 NTAPI
 132 Soft386StepInto(PSOFT386_STATE State)
 133 {
 134     /* Call the internal function */
 135     Soft386ExecutionControl(State, SOFT386_STEP_INTO);
 136 }
 137
 138 VOID
 139 NTAPI
 140 Soft386StepOver(PSOFT386_STATE State)
 141 {
 142     /* Call the internal function */
 143     Soft386ExecutionControl(State, SOFT386_STEP_OVER);
 144 }
 145
 146 VOID
 147 NTAPI
 148 Soft386StepOut(PSOFT386_STATE State)
 149 {
 150     /* Call the internal function */
 151     Soft386ExecutionControl(State, SOFT386_STEP_OUT);
 152 }
 153
 154 VOID
 155 NTAPI
 156 Soft386DumpState(PSOFT386_STATE State)
 157 {
 158     DPRINT1("\nCPU currently executing in %s mode at %04X:%08X\n"
 159             "Time Stamp Counter = %016X\n",
 160             (State->ControlRegisters[0] & SOFT386_CR0_PE) ? "protected" : "real",
 161             State->SegmentRegs[SOFT386_REG_CS].Selector,
 162             State->InstPtr.Long,
 163             State->TimeStampCounter);
 164     DPRINT1("\nGeneral purpose registers:\n"
 165             "EAX = %08X\tECX = %08X\tEDX = %08X\tEBX = %08X\n"
 166             "ESP = %08X\tEBP = %08X\tESI = %08X\tEDI = %08X\n",
 167             State->GeneralRegs[SOFT386_REG_EAX].Long,
 168             State->GeneralRegs[SOFT386_REG_ECX].Long,
 169             State->GeneralRegs[SOFT386_REG_EDX].Long,
 170             State->GeneralRegs[SOFT386_REG_EBX].Long,
 171             State->GeneralRegs[SOFT386_REG_ESP].Long,
 172             State->GeneralRegs[SOFT386_REG_EBP].Long,
 173             State->GeneralRegs[SOFT386_REG_ESI].Long,
 174             State->GeneralRegs[SOFT386_REG_EDI].Long);
 175     DPRINT1("\nSegment registers:\n"
 176             "ES = %04X (Base: %08X, Limit: %08X, Dpl: %u)\n"
 177             "CS = %04X (Base: %08X, Limit: %08X, Dpl: %u)\n"
 178             "SS = %04X (Base: %08X, Limit: %08X, Dpl: %u)\n"
 179             "DS = %04X (Base: %08X, Limit: %08X, Dpl: %u)\n"
 180             "FS = %04X (Base: %08X, Limit: %08X, Dpl: %u)\n"
 181             "GS = %04X (Base: %08X, Limit: %08X, Dpl: %u)\n",
 182             State->SegmentRegs[SOFT386_REG_ES].Selector,
 183             State->SegmentRegs[SOFT386_REG_ES].Base,
 184             State->SegmentRegs[SOFT386_REG_ES].Limit,
 185             State->SegmentRegs[SOFT386_REG_ES].Dpl,
 186             State->SegmentRegs[SOFT386_REG_CS].Selector,
 187             State->SegmentRegs[SOFT386_REG_CS].Base,
 188             State->SegmentRegs[SOFT386_REG_CS].Limit,
 189             State->SegmentRegs[SOFT386_REG_CS].Dpl,
 190             State->SegmentRegs[SOFT386_REG_SS].Selector,
 191             State->SegmentRegs[SOFT386_REG_SS].Base,
 192             State->SegmentRegs[SOFT386_REG_SS].Limit,
 193             State->SegmentRegs[SOFT386_REG_SS].Dpl,
 194             State->SegmentRegs[SOFT386_REG_DS].Selector,
 195             State->SegmentRegs[SOFT386_REG_DS].Base,
 196             State->SegmentRegs[SOFT386_REG_DS].Limit,
 197             State->SegmentRegs[SOFT386_REG_DS].Dpl,
 198             State->SegmentRegs[SOFT386_REG_FS].Selector,
 199             State->SegmentRegs[SOFT386_REG_FS].Base,
 200             State->SegmentRegs[SOFT386_REG_FS].Limit,
 201             State->SegmentRegs[SOFT386_REG_FS].Dpl,
 202             State->SegmentRegs[SOFT386_REG_GS].Selector,
 203             State->SegmentRegs[SOFT386_REG_GS].Base,
 204             State->SegmentRegs[SOFT386_REG_GS].Limit,
 205             State->SegmentRegs[SOFT386_REG_GS].Dpl);
 206     DPRINT1("\nFlags: %08X (%s %s %s %s %s %s %s %s %s %s %s %s %s %s %s) Iopl: %u\n",
 207             State->Flags.Long,
 208             State->Flags.Cf ? "CF" : "cf",
 209             State->Flags.Pf ? "PF" : "pf",
 210             State->Flags.Af ? "AF" : "af",
 211             State->Flags.Zf ? "ZF" : "zf",
 212             State->Flags.Sf ? "SF" : "sf",
 213             State->Flags.Tf ? "TF" : "tf",
 214             State->Flags.If ? "IF" : "if",
 215             State->Flags.Df ? "DF" : "df",
 216             State->Flags.Of ? "OF" : "of",
 217             State->Flags.Nt ? "NT" : "nt",
 218             State->Flags.Rf ? "RF" : "rf",
 219             State->Flags.Vm ? "VM" : "vm",
 220             State->Flags.Ac ? "AC" : "ac",
 221             State->Flags.Vif ? "VIF" : "vif",
 222             State->Flags.Vip ? "VIP" : "vip",
 223             State->Flags.Iopl);
 224     DPRINT1("\nControl Registers:\n"
 225             "CR0 = %08X\tCR1 = %08X\tCR2 = %08X\tCR3 = %08X\n"
 226             "CR4 = %08X\tCR5 = %08X\tCR6 = %08X\tCR7 = %08X\n",
 227             State->ControlRegisters[SOFT386_REG_CR0],
 228             State->ControlRegisters[SOFT386_REG_CR1],
 229             State->ControlRegisters[SOFT386_REG_CR2],
 230             State->ControlRegisters[SOFT386_REG_CR3],
 231             State->ControlRegisters[SOFT386_REG_CR4],
 232             State->ControlRegisters[SOFT386_REG_CR5],
 233             State->ControlRegisters[SOFT386_REG_CR6],
 234             State->ControlRegisters[SOFT386_REG_CR7]);
 235     DPRINT1("\nDebug Registers:\n"
 236             "DR0 = %08X\tDR1 = %08X\tDR2 = %08X\tDR3 = %08X\n"
 237             "DR4 = %08X\tDR5 = %08X\tDR6 = %08X\tDR7 = %08X\n",
 238             State->DebugRegisters[SOFT386_REG_DR0],
 239             State->DebugRegisters[SOFT386_REG_DR1],
 240             State->DebugRegisters[SOFT386_REG_DR2],
 241             State->DebugRegisters[SOFT386_REG_DR3],
 242             State->DebugRegisters[SOFT386_REG_DR4],
 243             State->DebugRegisters[SOFT386_REG_DR5],
 244             State->DebugRegisters[SOFT386_REG_DR6],
 245             State->DebugRegisters[SOFT386_REG_DR7]);
 246 }
 247
 248 VOID
 249 NTAPI
 250 Soft386Reset(PSOFT386_STATE State)
 251 {
 252     INT i;
 253     SOFT386_MEM_READ_PROC MemReadCallback = State->MemReadCallback;
 254     SOFT386_MEM_WRITE_PROC MemWriteCallback = State->MemWriteCallback;
 255     SOFT386_IO_READ_PROC IoReadCallback = State->IoReadCallback;
 256     SOFT386_IO_WRITE_PROC IoWriteCallback = State->IoWriteCallback;
 257     SOFT386_IDLE_PROC IdleCallback = State->IdleCallback;
 258     SOFT386_BOP_PROC BopCallback = State->BopCallback;
 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 < SOFT386_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[SOFT386_REG_CS].Selector = 0xF000;
 278     State->SegmentRegs[SOFT386_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[SOFT386_REG_CR0] |= SOFT386_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 }
 295
 296 VOID
 297 NTAPI
 298 Soft386Interrupt(PSOFT386_STATE State, UCHAR Number)
 299 {
 300     /* Set the hardware interrupt flag */
 301     State->HardwareInt = TRUE;
 302     State->PendingIntNum = Number;
 303 }
 304
 305 VOID
 306 NTAPI
 307 Soft386ExecuteAt(PSOFT386_STATE State, USHORT Segment, ULONG Offset)
 308 {
 309     /* Load the new CS */
 310     if (!Soft386LoadSegment(State, SOFT386_REG_CS, Segment))
 311     {
 312         /* An exception occurred, let the handler execute instead */
 313         return;
 314     }
 315
 316     /* Set the new IP */
 317     State->InstPtr.Long = Offset;
 318 }
 319
 320 VOID
 321 NTAPI
 322 Soft386SetStack(PSOFT386_STATE State, USHORT Segment, ULONG Offset)
 323 {
 324     /* Load the new SS */
 325     if (!Soft386LoadSegment(State, SOFT386_REG_SS, Segment))
 326     {
 327         /* An exception occurred, let the handler execute instead */
 328         return;
 329     }
 330
 331     /* Set the new SP */
 332     State->GeneralRegs[SOFT386_REG_ESP].Long = Offset;
 333 }
 334
 335 VOID
 336 NTAPI
 337 Soft386SetSegment(PSOFT386_STATE State,
 338                   SOFT386_SEG_REGS Segment,
 339                   USHORT Selector)
 340 {
 341     /* Call the internal function */
 342     Soft386LoadSegment(State, Segment, Selector);
 343 }
 344
 345 /* EOF */