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             /* Check if interrupts are enabled and there is an interrupt pending */
  65             if (State->Flags.If && State->HardwareInt)
  66             {
  67                 FAST486_IDT_ENTRY IdtEntry;
  68
  69                 /* Get the interrupt vector */
  70                 if (Fast486GetIntVector(State, State->PendingIntNum, &IdtEntry))
  71                 {
  72                     /* Perform the interrupt */
  73                     Fast486InterruptInternal(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 (!Fast486FetchByte(State, &Opcode)) continue;
  86
  87         // TODO: Check for CALL/RET to update ProcedureCallCount.
  88
  89         if (Fast486OpcodeHandlers[Opcode] != NULL)
  90         {
  91             /* Call the opcode handler */
  92             Fast486OpcodeHandlers[Opcode](State, Opcode);
  93         }
  94         else
  95         {
  96             /* This is not a valid opcode */
  97             Fast486Exception(State, FAST486_EXCEPTION_UD);
  98         }
  99
 100         if (Fast486OpcodeHandlers[Opcode] != Fast486OpcodePrefix)
 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     while ((Command == FAST486_CONTINUE)
 112            || (Command == FAST486_STEP_OVER && ProcedureCallCount > 0)
 113            || (Command == FAST486_STEP_OUT && ProcedureCallCount >= 0)
 114            || (Fast486OpcodeHandlers[Opcode] == Fast486OpcodePrefix));
 115 }
 116
 117 /* PUBLIC FUNCTIONS ***********************************************************/
 118
 119 VOID
 120 NTAPI
 121 Fast486Continue(PFAST486_STATE State)
 122 {
 123     /* Call the internal function */
 124     Fast486ExecutionControl(State, FAST486_CONTINUE);
 125 }
 126
 127 VOID
 128 NTAPI
 129 Fast486StepInto(PFAST486_STATE State)
 130 {
 131     /* Call the internal function */
 132     Fast486ExecutionControl(State, FAST486_STEP_INTO);
 133 }
 134
 135 VOID
 136 NTAPI
 137 Fast486StepOver(PFAST486_STATE State)
 138 {
 139     /* Call the internal function */
 140     Fast486ExecutionControl(State, FAST486_STEP_OVER);
 141 }
 142
 143 VOID
 144 NTAPI
 145 Fast486StepOut(PFAST486_STATE State)
 146 {
 147     /* Call the internal function */
 148     Fast486ExecutionControl(State, FAST486_STEP_OUT);
 149 }
 150
 151 VOID
 152 NTAPI
 153 Fast486DumpState(PFAST486_STATE State)
 154 {
 155     DPRINT1("\nCPU currently executing in %s mode at %04X:%08X\n",
 156             (State->ControlRegisters[0] & FAST486_CR0_PE) ? "protected" : "real",
 157             State->SegmentRegs[FAST486_REG_CS].Selector,
 158             State->InstPtr.Long);
 159     DPRINT1("\nGeneral purpose registers:\n"
 160             "EAX = %08X\tECX = %08X\tEDX = %08X\tEBX = %08X\n"
 161             "ESP = %08X\tEBP = %08X\tESI = %08X\tEDI = %08X\n",
 162             State->GeneralRegs[FAST486_REG_EAX].Long,
 163             State->GeneralRegs[FAST486_REG_ECX].Long,
 164             State->GeneralRegs[FAST486_REG_EDX].Long,
 165             State->GeneralRegs[FAST486_REG_EBX].Long,
 166             State->GeneralRegs[FAST486_REG_ESP].Long,
 167             State->GeneralRegs[FAST486_REG_EBP].Long,
 168             State->GeneralRegs[FAST486_REG_ESI].Long,
 169             State->GeneralRegs[FAST486_REG_EDI].Long);
 170     DPRINT1("\nSegment registers:\n"
 171             "ES = %04X (Base: %08X, Limit: %08X, Dpl: %u)\n"
 172             "CS = %04X (Base: %08X, Limit: %08X, Dpl: %u)\n"
 173             "SS = %04X (Base: %08X, Limit: %08X, Dpl: %u)\n"
 174             "DS = %04X (Base: %08X, Limit: %08X, Dpl: %u)\n"
 175             "FS = %04X (Base: %08X, Limit: %08X, Dpl: %u)\n"
 176             "GS = %04X (Base: %08X, Limit: %08X, Dpl: %u)\n",
 177             State->SegmentRegs[FAST486_REG_ES].Selector,
 178             State->SegmentRegs[FAST486_REG_ES].Base,
 179             State->SegmentRegs[FAST486_REG_ES].Limit,
 180             State->SegmentRegs[FAST486_REG_ES].Dpl,
 181             State->SegmentRegs[FAST486_REG_CS].Selector,
 182             State->SegmentRegs[FAST486_REG_CS].Base,
 183             State->SegmentRegs[FAST486_REG_CS].Limit,
 184             State->SegmentRegs[FAST486_REG_CS].Dpl,
 185             State->SegmentRegs[FAST486_REG_SS].Selector,
 186             State->SegmentRegs[FAST486_REG_SS].Base,
 187             State->SegmentRegs[FAST486_REG_SS].Limit,
 188             State->SegmentRegs[FAST486_REG_SS].Dpl,
 189             State->SegmentRegs[FAST486_REG_DS].Selector,
 190             State->SegmentRegs[FAST486_REG_DS].Base,
 191             State->SegmentRegs[FAST486_REG_DS].Limit,
 192             State->SegmentRegs[FAST486_REG_DS].Dpl,
 193             State->SegmentRegs[FAST486_REG_FS].Selector,
 194             State->SegmentRegs[FAST486_REG_FS].Base,
 195             State->SegmentRegs[FAST486_REG_FS].Limit,
 196             State->SegmentRegs[FAST486_REG_FS].Dpl,
 197             State->SegmentRegs[FAST486_REG_GS].Selector,
 198             State->SegmentRegs[FAST486_REG_GS].Base,
 199             State->SegmentRegs[FAST486_REG_GS].Limit,
 200             State->SegmentRegs[FAST486_REG_GS].Dpl);
 201     DPRINT1("\nFlags: %08X (%s %s %s %s %s %s %s %s %s %s %s %s %s %s %s) Iopl: %u\n",
 202             State->Flags.Long,
 203             State->Flags.Cf ? "CF" : "cf",
 204             State->Flags.Pf ? "PF" : "pf",
 205             State->Flags.Af ? "AF" : "af",
 206             State->Flags.Zf ? "ZF" : "zf",
 207             State->Flags.Sf ? "SF" : "sf",
 208             State->Flags.Tf ? "TF" : "tf",
 209             State->Flags.If ? "IF" : "if",
 210             State->Flags.Df ? "DF" : "df",
 211             State->Flags.Of ? "OF" : "of",
 212             State->Flags.Nt ? "NT" : "nt",
 213             State->Flags.Rf ? "RF" : "rf",
 214             State->Flags.Vm ? "VM" : "vm",
 215             State->Flags.Ac ? "AC" : "ac",
 216             State->Flags.Vif ? "VIF" : "vif",
 217             State->Flags.Vip ? "VIP" : "vip",
 218             State->Flags.Iopl);
 219     DPRINT1("\nControl Registers:\n"
 220             "CR0 = %08X\tCR2 = %08X\tCR3 = %08X\n",
 221             State->ControlRegisters[FAST486_REG_CR0],
 222             State->ControlRegisters[FAST486_REG_CR2],
 223             State->ControlRegisters[FAST486_REG_CR3]);
 224     DPRINT1("\nDebug Registers:\n"
 225             "DR0 = %08X\tDR1 = %08X\tDR2 = %08X\n"
 226             "DR3 = %08X\tDR4 = %08X\tDR5 = %08X\n",
 227             State->DebugRegisters[FAST486_REG_DR0],
 228             State->DebugRegisters[FAST486_REG_DR1],
 229             State->DebugRegisters[FAST486_REG_DR2],
 230             State->DebugRegisters[FAST486_REG_DR3],
 231             State->DebugRegisters[FAST486_REG_DR4],
 232             State->DebugRegisters[FAST486_REG_DR5]);
 233 }
 234
 235 VOID
 236 NTAPI
 237 Fast486Reset(PFAST486_STATE State)
 238 {
 239     INT i;
 240     FAST486_MEM_READ_PROC MemReadCallback = State->MemReadCallback;
 241     FAST486_MEM_WRITE_PROC MemWriteCallback = State->MemWriteCallback;
 242     FAST486_IO_READ_PROC IoReadCallback = State->IoReadCallback;
 243     FAST486_IO_WRITE_PROC IoWriteCallback = State->IoWriteCallback;
 244     FAST486_IDLE_PROC IdleCallback = State->IdleCallback;
 245     FAST486_BOP_PROC BopCallback = State->BopCallback;
 246
 247     /* Clear the entire structure */
 248     RtlZeroMemory(State, sizeof(*State));
 249
 250     /* Initialize the registers */
 251     State->Flags.AlwaysSet = 1;
 252     State->InstPtr.LowWord = 0xFFF0;
 253
 254     /* Initialize segments */
 255     for (i = 0; i < FAST486_NUM_SEG_REGS; i++)
 256     {
 257         /* Set the selector, base and limit, other values don't apply in real mode */
 258         State->SegmentRegs[i].Selector = 0;
 259         State->SegmentRegs[i].Base = 0;
 260         State->SegmentRegs[i].Limit = 0xFFFF;
 261     }
 262
 263     /* Initialize the code segment */
 264     State->SegmentRegs[FAST486_REG_CS].Selector = 0xF000;
 265     State->SegmentRegs[FAST486_REG_CS].Base = 0xFFFF0000;
 266
 267     /* Initialize the IDT */
 268     State->Idtr.Size = 0x3FF;
 269     State->Idtr.Address = 0;
 270
 271     /* Initialize CR0 */
 272     State->ControlRegisters[FAST486_REG_CR0] |= FAST486_CR0_ET;
 273
 274     /* Restore the callbacks */
 275     State->MemReadCallback = MemReadCallback;
 276     State->MemWriteCallback = MemWriteCallback;
 277     State->IoReadCallback = IoReadCallback;
 278     State->IoWriteCallback = IoWriteCallback;
 279     State->IdleCallback = IdleCallback;
 280     State->BopCallback = BopCallback;
 281 }
 282
 283 VOID
 284 NTAPI
 285 Fast486Interrupt(PFAST486_STATE State, UCHAR Number)
 286 {
 287     /* Set the hardware interrupt flag */
 288     State->HardwareInt = TRUE;
 289     State->PendingIntNum = Number;
 290 }
 291
 292 VOID
 293 NTAPI
 294 Fast486ExecuteAt(PFAST486_STATE State, USHORT Segment, ULONG Offset)
 295 {
 296     /* Load the new CS */
 297     if (!Fast486LoadSegment(State, FAST486_REG_CS, Segment))
 298     {
 299         /* An exception occurred, let the handler execute instead */
 300         return;
 301     }
 302
 303     /* Set the new IP */
 304     State->InstPtr.Long = Offset;
 305 }
 306
 307 VOID
 308 NTAPI
 309 Fast486SetStack(PFAST486_STATE State, USHORT Segment, ULONG Offset)
 310 {
 311     /* Load the new SS */
 312     if (!Fast486LoadSegment(State, FAST486_REG_SS, Segment))
 313     {
 314         /* An exception occurred, let the handler execute instead */
 315         return;
 316     }
 317
 318     /* Set the new SP */
 319     State->GeneralRegs[FAST486_REG_ESP].Long = Offset;
 320 }
 321
 322 VOID
 323 NTAPI
 324 Fast486SetSegment(PFAST486_STATE State,
 325                   FAST486_SEG_REGS Segment,
 326                   USHORT Selector)
 327 {
 328     /* Call the internal function */
 329     Fast486LoadSegment(State, Segment, Selector);
 330 }
 331
 332 /* EOF */