git.maemo.org Git - drnoksnes/blob - cpuexec.cpp

   1 /*
   2  * Snes9x - Portable Super Nintendo Entertainment System (TM) emulator.
   3  *
   4  * (c) Copyright 1996 - 2001 Gary Henderson (gary.henderson@ntlworld.com) and
   5  *                           Jerremy Koot (jkoot@snes9x.com)
   6  *
   7  * Super FX C emulator code
   8  * (c) Copyright 1997 - 1999 Ivar (ivar@snes9x.com) and
   9  *                           Gary Henderson.
  10  * Super FX     assembler emulator code (c) Copyright 1998 zsKnight and _Demo_.
  11  *
  12  * DSP1 emulator code (c) Copyright 1998 Ivar, _Demo_ and Gary Henderson.
  13  * C4 asm and some C emulation code (c) Copyright 2000 zsKnight and _Demo_.
  14  * C4 C code (c) Copyright 2001 Gary Henderson (gary.henderson@ntlworld.com).
  15  *
  16  * DOS port code contains the works of other authors. See headers in
  17  * individual files.
  18  *
  19  * Snes9x homepage: http://www.snes9x.com
  20  *
  21  * Permission to use, copy, modify and distribute Snes9x in both binary and
  22  * source form, for non-commercial purposes, is hereby granted without fee,
  23  * providing that this license information and copyright notice appear with
  24  * all copies and any derived work.
  25  *
  26  * This software is provided 'as-is', without any express or implied
  27  * warranty. In no event shall the authors be held liable for any damages
  28  * arising from the use of this software.
  29  *
  30  * Snes9x is freeware for PERSONAL USE only. Commercial users should
  31  * seek permission of the copyright holders first. Commercial use includes
  32  * charging money for Snes9x or software derived from Snes9x.
  33  *
  34  * The copyright holders request that bug fixes and improvements to the code
  35  * should be forwarded to them so everyone can benefit from the modifications
  36  * in future versions.
  37  *
  38  * Super NES and Super Nintendo Entertainment System are trademarks of
  39  * Nintendo Co., Limited and its subsidiary companies.
  40  */
  41
  42
  43
  44 #include "snes9x.h"
  45
  46 #include "memmap.h"
  47 #include "ppu.h"
  48 #include "cpuexec.h"
  49 #include "debug.h"
  50 #include "snapshot.h"
  51 #include "gfx.h"
  52 #include "missing.h"
  53 #include "apu.h"
  54 #include "dma.h"
  55 #include "fxemu.h"
  56
  57 #if !CONF_BUILD_ASM_CPU
  58 #include "cpuops.h"
  59 #endif
  60
  61 #ifdef USE_SA1
  62 #include "sa1.h"
  63 #endif
  64
  65
  66 #if CONF_BUILD_ASM_CPU
  67 #include "os9x_asm_cpu.h"
  68 // for asm core:
  69 uint16 mem_check=0;
  70 #endif
  71
  72 #if defined(__showframe__)
  73 int framecpt=0;
  74 #endif
  75
  76 void S9xMainLoop (void)
  77 {
  78 #if defined(__showframe__)
  79         framecpt++;
  80         char stra[64];
  81         sprintf(stra,"framecpt : %d",framecpt);
  82         S9xMessage(0,0,stra);
  83 #endif
  84
  85 #if CONF_BUILD_ASM_CPU
  86         asmMainLoop(&CPU);
  87 #else
  88         for (;;) {
  89                 APU_EXECUTE(1);
  90                 if (CPU.Flags) {
  91                         if (CPU.Flags & NMI_FLAG) {
  92                                 if (--CPU.NMICycleCount == 0) {
  93                                         CPU.Flags &= ~NMI_FLAG;
  94                                         if (CPU.WaitingForInterrupt) {
  95                                                 CPU.WaitingForInterrupt = FALSE;
  96                                                 CPU.PC++;
  97                                         }
  98                                         S9xOpcode_NMI ();
  99                                 }
 100                         }
 101
 102                         if (CPU.Flags & IRQ_PENDING_FLAG) {
 103                                 if (CPU.IRQCycleCount == 0)     {
 104                                         if (CPU.WaitingForInterrupt) {
 105                                                 CPU.WaitingForInterrupt = FALSE;
 106                                                 CPU.PC++;
 107                                         }
 108                                         if (CPU.IRQActive && !Settings.DisableIRQ) {
 109                                                 if (!CheckFlag(IRQ))
 110                                                         S9xOpcode_IRQ ();
 111                                         } else {
 112                                                 CPU.Flags &= ~IRQ_PENDING_FLAG;
 113                                         }
 114                                 } else {
 115                                         CPU.IRQCycleCount--;
 116                                 }
 117                         }
 118
 119                         if (CPU.Flags & SCAN_KEYS_FLAG)
 120                                 break;
 121                 }
 122
 123 #ifdef CPU_SHUTDOWN
 124                 CPU.PCAtOpcodeStart = CPU.PC;
 125 #endif
 126                 CPU.Cycles += CPU.MemSpeed;
 127
 128                 (*ICPU.S9xOpcodes[*CPU.PC++].S9xOpcode) ();
 129
 130 #ifdef USE_SA1
 131                 if (SA1.Executing)
 132                         S9xSA1MainLoop ();
 133 #endif
 134
 135                 DO_HBLANK_CHECK ();
 136         }
 137 #endif
 138
 139     Registers.PC = CPU.PC - CPU.PCBase;
 140 #if !CONF_BUILD_ASM_CPU
 141     S9xPackStatus ();
 142 #endif
 143     S9xAPUPackStatus ();
 144
 145     if (CPU.Flags & SCAN_KEYS_FLAG)
 146     {
 147                 CPU.Flags &= ~SCAN_KEYS_FLAG;
 148     }
 149
 150     if (CPU.BRKTriggered && Settings.SuperFX && !CPU.TriedInterleavedMode2)
 151     {
 152         CPU.TriedInterleavedMode2 = TRUE;
 153         CPU.BRKTriggered = FALSE;
 154         S9xDeinterleaveMode2 ();
 155     }
 156 }
 157
 158 void S9xSetIRQ (uint32 source)
 159 {
 160     CPU.IRQActive |= source;
 161     CPU.Flags |= IRQ_PENDING_FLAG;
 162     CPU.IRQCycleCount = 3;
 163     if (CPU.WaitingForInterrupt)
 164     {
 165         // Force IRQ to trigger immediately after WAI -
 166         // Final Fantasy Mystic Quest crashes without this.
 167         CPU.IRQCycleCount = 0;
 168         CPU.WaitingForInterrupt = FALSE;
 169         CPU.PC++;
 170     }
 171 }
 172
 173 void S9xClearIRQ (uint32 source)
 174 {
 175     CLEAR_IRQ_SOURCE (source);
 176 }
 177
 178
 179 void S9xDoHBlankProcessing ()
 180 {
 181 #ifdef CPU_SHUTDOWN
 182     CPU.WaitCounter++;
 183 #endif
 184     switch (CPU.WhichEvent)
 185     {
 186     case HBLANK_START_EVENT:
 187                 if (IPPU.HDMA && CPU.V_Counter <= PPU.ScreenHeight)
 188                         IPPU.HDMA = S9xDoHDMA (IPPU.HDMA);
 189                 break;
 190
 191     case HBLANK_END_EVENT:
 192                 APU_EXECUTE(3); // notaz: run spc700 in sound 'speed hack' mode
 193
 194                 if(Settings.SuperFX)
 195                         S9xSuperFXExec ();
 196
 197                 CPU.Cycles -= Settings.H_Max;
 198                 if (/*IAPU.APUExecuting*/CPU.APU_APUExecuting)
 199                         CPU.APU_Cycles -= Settings.H_Max;
 200                 else
 201                         CPU.APU_Cycles = 0;
 202
 203                 CPU.NextEvent = -1;
 204                 ICPU.Scanline++;
 205
 206                 if (++CPU.V_Counter > (Settings.PAL ? SNES_MAX_PAL_VCOUNTER : SNES_MAX_NTSC_VCOUNTER))
 207                 {
 208                         PPU.OAMAddr = PPU.SavedOAMAddr;
 209                         PPU.OAMFlip = 0;
 210                         CPU.V_Counter = 0;
 211                         CPU.NMIActive = FALSE;
 212                         ICPU.Frame++;
 213                         PPU.HVBeamCounterLatched = 0;
 214                         CPU.Flags |= SCAN_KEYS_FLAG;
 215                         S9xStartHDMA ();
 216                 }
 217
 218                 if (PPU.VTimerEnabled && !PPU.HTimerEnabled &&
 219                         CPU.V_Counter == PPU.IRQVBeamPos)
 220                 {
 221                         S9xSetIRQ (PPU_V_BEAM_IRQ_SOURCE);
 222                 }
 223
 224                 if (CPU.V_Counter == PPU.ScreenHeight + FIRST_VISIBLE_LINE)
 225                 {
 226                         // Start of V-blank
 227                         S9xEndScreenRefresh ();
 228                         PPU.FirstSprite = 0;
 229                         IPPU.HDMA = 0;
 230                         // Bits 7 and 6 of $4212 are computed when read in S9xGetPPU.
 231                         missing.dma_this_frame = 0;
 232                         IPPU.MaxBrightness = PPU.Brightness;
 233                         PPU.ForcedBlanking = (Memory.FillRAM [0x2100] >> 7) & 1;
 234
 235                         Memory.FillRAM[0x4210] = 0x80;
 236                         if (Memory.FillRAM[0x4200] & 0x80)
 237                         {
 238                         CPU.NMIActive = TRUE;
 239                         CPU.Flags |= NMI_FLAG;
 240                         CPU.NMICycleCount = CPU.NMITriggerPoint;
 241                         }
 242                         }
 243
 244                 if (CPU.V_Counter == PPU.ScreenHeight + 3)
 245                         S9xUpdateJoypads ();
 246
 247                 if (CPU.V_Counter == FIRST_VISIBLE_LINE)
 248                 {
 249                         Memory.FillRAM[0x4210] = 0;
 250                         CPU.Flags &= ~NMI_FLAG;
 251                         S9xStartScreenRefresh ();
 252                 }
 253                 if (CPU.V_Counter >= FIRST_VISIBLE_LINE &&
 254                         CPU.V_Counter < PPU.ScreenHeight + FIRST_VISIBLE_LINE)
 255                 {
 256                         RenderLine (CPU.V_Counter - FIRST_VISIBLE_LINE);
 257                 }
 258                 // Use TimerErrorCounter to skip update of SPC700 timers once
 259                 // every 128 updates. Needed because this section of code is called
 260                 // once every emulated 63.5 microseconds, which coresponds to
 261                 // 15.750KHz, but the SPC700 timers need to be updated at multiples
 262                 // of 8KHz, hence the error correction.
 263         //      IAPU.TimerErrorCounter++;
 264         //      if (IAPU.TimerErrorCounter >= )
 265         //          IAPU.TimerErrorCounter = 0;
 266         //      else
 267                 {
 268                         if (APU.TimerEnabled [2])
 269                         {
 270                         APU.Timer [2] += 4;
 271                         while (APU.Timer [2] >= APU.TimerTarget [2])
 272                         {
 273                                 IAPU.RAM [0xff] = (IAPU.RAM [0xff] + 1) & 0xf;
 274                                 APU.Timer [2] -= APU.TimerTarget [2];
 275 #ifdef SPC700_SHUTDOWN
 276                                 IAPU.WaitCounter++;
 277                                 /*IAPU.APUExecuting*/CPU.APU_APUExecuting= TRUE;
 278 #endif
 279                         }
 280                         }
 281                         if (CPU.V_Counter & 1)
 282                         {
 283                         if (APU.TimerEnabled [0])
 284                         {
 285                                 APU.Timer [0]++;
 286                                 if (APU.Timer [0] >= APU.TimerTarget [0])
 287                                 {
 288                                 IAPU.RAM [0xfd] = (IAPU.RAM [0xfd] + 1) & 0xf;
 289                                 APU.Timer [0] = 0;
 290 #ifdef SPC700_SHUTDOWN
 291                                 IAPU.WaitCounter++;
 292                                 /*IAPU.APUExecuting*/CPU.APU_APUExecuting = TRUE;
 293 #endif
 294                                 }
 295                         }
 296                         if (APU.TimerEnabled [1])
 297                         {
 298                                 APU.Timer [1]++;
 299                                 if (APU.Timer [1] >= APU.TimerTarget [1])
 300                                 {
 301                                 IAPU.RAM [0xfe] = (IAPU.RAM [0xfe] + 1) & 0xf;
 302                                 APU.Timer [1] = 0;
 303 #ifdef SPC700_SHUTDOWN
 304                                 IAPU.WaitCounter++;
 305                                 /*IAPU.APUExecuting*/CPU.APU_APUExecuting = TRUE;
 306 #endif
 307                                 }
 308                         }
 309                         }
 310                 }
 311                 break;
 312         case HTIMER_BEFORE_EVENT:
 313         case HTIMER_AFTER_EVENT:
 314                 if (PPU.HTimerEnabled &&
 315                         (!PPU.VTimerEnabled || CPU.V_Counter == PPU.IRQVBeamPos))
 316                 {
 317                         S9xSetIRQ (PPU_H_BEAM_IRQ_SOURCE);
 318                 }
 319                 break;
 320     }
 321     S9xReschedule ();
 322 }