+added Game Genie hardware emulation (Game Genie ROM is now fully supported)

HISTORY.txt

@@ -1,22 +1,24 @@
 ---------------------------------------------------------------------------------------------------------
-Genesis Plus GX 1.3.2 (??/??/????) (Eke-Eke)
+Genesis Plus GX 1.4.0 (??/??/????) (Eke-Eke)
 ---------------------------------------------------------------------------------------------------------
 
 [Core]
 ------
 
-* optimized SN76489 core
+* modified SN76489 cut-off frequency
-* modified SN76489 cut-off frequency (thanks to Steve Snake)
+* implemented optimized SN76489 core from Blargg that uses Blip Buffer linear synthesis (Noise Channel is now linear interpolated)
-* modified SN76489 core to use Blip Buffer linear synthesis , Noise channel is now linear averaged (thanks to Blargg)
 * added an option to boost SN76489 Noise Channel
-* removed now outdated Gens YM2612 core
+* removed outdated Gens YM2612 core
-* improved YM2612 emulation accuracy (SSG-EG, CSM mode...) (thanks to Nemesis for his tests on real hardware)
+* improved YM2612 core general accuracy (SSG-EG, CSM mode,...) (based upon Nemesis recent tests on real MD)
+* improved YM2612 LFO emulation (fixes "Spider-Man & Venom : Separation Anxiety" intro music)
 * fixed YM2612 context saving/loading.
-* added 3 Band Equalizer for improved & fully configurable sound filtering (taken from Softdev's NeoCD Redux)
+* added 3-Band EQ for fully configurable sound filtering (credits to Neil C / Etanza Systems)
-* improved sprites masking emulation: fixes 3D level in Mickey Mania (thanks to Nemesis for his test program)
+* implemented faster and better FIR resampler, removed libsamplerate support (thanks to Blargg and AamirM), Virtua Racing now plays fullspeed
+when High Quality FM is enabled.
+* improved VDP sprite masking emulation: fixes 3D level in Mickey Mania (thanks to Nemesis for his sprite test program)
 * fixed lightgun autodetection: fixes cursor position in Lethal Enforcers II
-* improved DIVU/DVIS (thanks to Jorge Cwik) & MULU/MULS instructions timing accuracy 
+* improved DIVU/DVIS (thanks to Jorge Cwik) & MULU/MULS 68k instructions timing accuracy 
-* lots of code cleanup & core optimizations
+* various code cleanup & core optimizations
 
 [Gamecube/Wii]
 
@@ -24,8 +26,8 @@ Genesis Plus GX 1.3.2 (??/??/????) (Eke-Eke)
 * fixed stability issues and some (potential) memory leaks
 * added internal screenshot feature
 * improved lightgun cursors
-* new FONT & GUI engines: use internal IPL FONT, GX hardware & multithreading for fast rendering.
+* implemented new FONT & GUI engines: use internal IPL FONT, GX hardware & multithreading for fast rendering.
-* new interface: incl. IR pointing, ROM snapshots, menu effects, sound effects, BGM... (check the README for more details)
+* implemented new interface: incl. IR pointing, ROM snapshots, menu effects, sound effects, BGM... (check the README for more details)
 
 
 

source/cart_hw/cart_hw.c

@@ -151,6 +151,9 @@ void cart_hw_reset()
 
   /* SVP chip */
   if (svp) svp_reset();
+
+  /* Game Genie hardware */
+  if (config.lock_on == CART_GG) ggenie_reset();
 }
 
 /* cart hardware detection */
@@ -222,6 +225,11 @@ void cart_hw_init()
     }
   }
 
+  /**********************************************
+          GAME GENIE 
+  ***********************************************/
+  if (config.lock_on == CART_GG) ggenie_init();
+
   /**********************************************
           SVP CHIP 
   ***********************************************/

source/cart_hw/cart_hw.h

@@ -27,6 +27,12 @@
 #ifndef _CART_HW_H_
 #define _CART_HW_H_
 
+/* Lock-ON cartridge devices */
+#define NO_CART  0 /* no connections */
+#define CART_GG  1 /* game genie */
+#define CART_AR  2 /* action replay */
+#define CART_SK  3 /* Sonic & Knuckles  */
+
 /* Hardware description */
 typedef struct
 {

source/cart_hw/ggenie.c

@@ -0,0 +1,217 @@
+/****************************************************************************
+ *  Genesis Plus
+ *  Game Genie Hardware emulation
+ *
+ *  Copyright (C) 2009  Eke-Eke (GCN/Wii port)
+ *
+ *  Based on documentation from Charles McDonald
+ *  (http://cgfm2.emuviews.com/txt/genie.txt)
+ *
+ *  This program is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation; either version 2 of the License, or
+ *  (at your option) any later version.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program; if not, write to the Free Software
+ *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ ***************************************************************************/
+
+#include "shared.h"
+
+static struct
+{
+  uint8 enabled;
+  uint8 rom[0x10000];
+  uint16 regs[0x20];
+  uint16 old[6];
+  uint16 data[6];
+  uint32 addr[6];
+} ggenie;
+
+static void ggenie_write_byte(uint32 address, uint32 data);
+static void ggenie_write_word(uint32 address, uint32 data);
+static void ggenie_write_regs(uint8 offset, uint32 data, uint8 type);
+static uint32 ggenie_read_regs(uint32 address);
+
+void ggenie_init(void)
+{
+  memset(&ggenie,0,sizeof(ggenie));
+
+  /* load Game Genie ROM program */
+  FILE *f = fopen(GAMEGENIE_ROM,"rb");
+  if (!f) return;
+  fread(ggenie.rom,1,0x8000,f);
+  fclose(f);
+
+  /* $0000-$7fff mirrored into $8000-$ffff */
+  memcpy(ggenie.rom+0x8000,ggenie.rom,0x8000);
+
+#ifdef LSB_FIRST
+  /* Byteswap ROM */
+  int i;
+  uint8 temp;
+  for(i = 0; i < 0x10000; i += 2)
+  {
+    temp = ggenie.rom[i];
+    ggenie.rom[i] = ggenie.rom[i+1];
+    ggenie.rom[i+1] = temp;
+  }
+#endif
+
+  /* set flag */
+  ggenie.enabled = 1;
+}
+
+void ggenie_reset(void)
+{
+  if (!ggenie.enabled) return;
+
+  /* restore patched ROM */
+  int i;
+  for (i=0; i<6; i++)
+  {
+    if (ggenie.regs[0] & (1 << i))
+      *(uint16 *)(cart_rom + ggenie.addr[i]) = ggenie.old[i];
+  }
+
+  /* reset internal state */
+  memset(ggenie.regs,0,sizeof(ggenie.regs));
+  memset(ggenie.old,0,sizeof(ggenie.old));
+  memset(ggenie.data,0,sizeof(ggenie.data));
+  memset(ggenie.addr,0,sizeof(ggenie.addr));
+
+  /* default slot mapping */
+  /* reads  are mapped to Game Genie ROM */
+  /* writes are mapped to Game Genie internal registers */
+  m68k_memory_map[0].base     = ggenie.rom;
+  m68k_memory_map[0].write8   = ggenie_write_byte;
+  m68k_memory_map[0].write16  = ggenie_write_word;
+  m68k_memory_map[0].read16   = NULL;
+}
+
+
+/* Byte write handler */
+/* Note: 2nd revision of the Game Genie software use byte writes to set registe values on exit */
+static void ggenie_write_byte(uint32 address, uint32 data)
+{
+  /* Lock bit */
+  if (ggenie.regs[0] & 0x100) return;
+
+  /* Register offset */
+  uint8 offset = (address >> 1) & 0x1f;
+
+  /* Write internal register (lower or upper BYTE) */
+  ggenie_write_regs(offset,data,address & 1);
+}
+
+/* Word write handler */
+static void ggenie_write_word(uint32 address, uint32 data)
+{
+  /* Lock bit */
+  if (ggenie.regs[0] & 0x100) return;
+
+  /* Register offset */
+  uint8 offset = (address >> 1) & 0x1f;
+
+  /* Write internal register (full WORD) */
+  ggenie_write_regs(offset,data,2);
+}
+
+static void ggenie_write_regs(uint8 offset, uint32 data, uint8 type)
+{
+  /* access type */
+  switch (type) 
+  {
+    case 0:   /* upper byte write */
+      data = (ggenie.regs[offset] & 0x00ff) | ((data & 0xff) << 8);
+      break;
+
+    case 1:   /* lower byte write */
+      data = (ggenie.regs[offset] & 0xff00) | (data & 0xff);
+      break;
+
+    default:
+      break;
+  }
+
+  /* Mode Register */
+  if (!offset)
+  {
+    /* by default, registers are write only */
+    m68k_memory_map[0].read16 = NULL;
+
+    /* MODE bits */
+    if (data & 0x400)
+    {
+      /* $0000-$7ffff reads mapped to Cartridge ROM */
+      m68k_memory_map[0].base = cart_rom;
+    }
+    else
+    {
+      /* $0000-$7ffff reads mapped to Game Genie ROM */
+      m68k_memory_map[0].base = ggenie.rom;
+
+      if (data & 0x200)
+      {
+        /* $0000-$7ffff reads mapped to Game Genie Registers */
+        /* code doing this should execute in RAM so we don't need to modify base address */
+        m68k_memory_map[0].read16 = ggenie_read_regs; 
+      }
+    }
+
+    /* LOCK bit */
+    if ((data & 0x100) && !(ggenie.regs[0] & 0x100))
+    {
+      /* patch ROM when GG program exits (LOCK bit set) */
+      /* this is done here to handle patched program reads faster & more easily */
+      /* on real HW, address decoding would be done on each reads */
+      int i,j;
+      for (i=0; i<6; i++)
+      {
+        /* decode patch address */
+        /* note: Charles's documment is wrong, first register holds bits 23-16 of patch address */
+        ggenie.addr[i] = (ggenie.regs[2+3*i] << 16) | ggenie.regs[3+3*i];
+
+        /* decode patch data */
+        ggenie.data[i] = ggenie.regs[4+3*i];
+
+        /* patch is enabled ? */
+        if (data & (1 << i))
+        {
+          /* first look if address has not already been patched */
+          for (j=0;j<i;j++)
+          {
+            if (ggenie.addr[i] == ggenie.addr[j])
+            {
+              /* disable code for later initialization */
+              data &= ~(1 << i);
+            }
+          }
+
+          /* ave old value and patch ROM if enabled */
+          if (data & (1 << i))
+          {
+            ggenie.old[i] = *(uint16 *)(cart_rom + ggenie.addr[i]);
+            *(uint16 *)(cart_rom + ggenie.addr[i]) = ggenie.data[i];
+          }
+        }
+      }
+    }
+  }
+
+  /* update internal register */
+  ggenie.regs[offset] = data;
+}
+
+static uint32 ggenie_read_regs(uint32 address)
+{
+  if (address < 0x40) return ggenie.regs[address >> 1];
+  else  return *(uint16 *)(cart_rom + address);
+}
+

source/cart_hw/ggenie.h

@@ -0,0 +1,30 @@
+/****************************************************************************
+ *  Genesis Plus
+ *  Game Genie Hardware emulation
+ *
+ *  Copyright (C) 2009  Eke-Eke (GCN/Wii port)
+ *
+ *  Based on documentation from Charles McDonald
+ *  (http://cgfm2.emuviews.com/txt/genie.txt)
+ *
+ *  This program is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation; either version 2 of the License, or
+ *  (at your option) any later version.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program; if not, write to the Free Software
+ *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ ***************************************************************************/
+
+/* global variables */
+extern int gamegenie;
+
+/* Function prototypes */
+extern void ggenie_init(void);
+extern void ggenie_reset(void);

source/gx/config.c

@@ -80,6 +80,7 @@ void config_default(void)
   config.force_dtack    = 0;
   config.addr_error     = 1;
   config.bios_enabled   = 0;
+  config.lock_on = NO_CART;
 
   /* video options */
   config.xshift   = 0;

source/gx/config.h

@@ -43,6 +43,7 @@ typedef struct
   uint8 force_dtack;
   uint8 addr_error;
   uint8 bios_enabled;
+  uint8 lock_on;
   int16 xshift;
   int16 yshift;
   int16 xscale;

source/gx/gui/menu.c

@@ -230,12 +230,13 @@ static gui_item items_audio[8] =
 };
 
 /* System options menu */
-static gui_item items_system[5] =
+static gui_item items_system[6] =
 {
   {NULL,NULL,"Console Region: AUTO",  "Select system region",                     52,132,276,48},
   {NULL,NULL,"System Lockups: OFF",   "Enable/disable original system lock-ups",  52,132,276,48},
   {NULL,NULL,"68k Address Error: ON", "Enable/disable 68k Address Error",         52,132,276,48},
   {NULL,NULL,"System BIOS: OFF",      "Enable/disable TMSS BIOS support",         52,132,276,48},
+  {NULL,NULL,"Lock-on: OFF",          "Select Lock-On cartridge type",            52,132,276,48},
   {NULL,NULL,"SVP Cycles: 1500",      "Adjust SVP chip emulation speed",          52,132,276,48}
 };
 
@@ -410,7 +411,7 @@ static gui_menu menu_system =
 {
   "System Settings",
   0,0,
-  5,4,6,
+  6,4,6,
   items_system,
   buttons_list,
   bg_list,
@@ -833,16 +834,18 @@ static void systemmenu ()
   sprintf (items[1].text, "System Lockups: %s", config.force_dtack ? "OFF" : "ON");
   sprintf (items[2].text, "68k Address Error: %s", config.addr_error ? "ON" : "OFF");
   sprintf (items[3].text, "System BIOS: %s", (config.bios_enabled & 1) ? "ON":"OFF");
+  if (config.lock_on == CART_GG) sprintf (items[4].text, "Lock-On: GAME GENIE");
+  else  sprintf (items[4].text, "Lock-On: OFF");
 
   if (svp)
   {
-    sprintf (items[4].text, "SVP Cycles: %d", SVP_cycles);
+    sprintf (items[5].text, "SVP Cycles: %d", SVP_cycles);
-    m->max_items = 5;
+    m->max_items = 6;
   }
   else
   {
-    m->max_items = 4;
+    m->max_items = 5;
-    m->offset = 0;
+    if (m->offset > 1) m->offset =1;
   }
 
   GUI_InitMenu(m);
@@ -909,7 +912,13 @@ static void systemmenu ()
         }
         break;
 
-      case 4:  /*** SVP emulation ***/
+      case 4:  /*** Cart Lock-On ***/
+        config.lock_on++;
+        if (config.lock_on > CART_GG) config.lock_on = NO_CART;
+        if (config.lock_on == CART_GG) sprintf (items[4].text, "Lock-On: GAME GENIE");
+        else  sprintf (items[4].text, "Lock-On: OFF");
+
+      case 5:  /*** SVP emulation ***/
         GUI_OptionBox(m,0,"SVP Cycles",(void *)&SVP_cycles,1,1,1500,1);
         sprintf (items[4].text, "SVP Cycles: %d", SVP_cycles);
         break;

source/gx/main.c

@@ -54,14 +54,11 @@ static void Power_Off(void)
  ***************************************************************************/
 static void load_bios(void)
 {
-  char pathname[MAXPATHLEN];
-
   /* reset BIOS found flag */
   config.bios_enabled &= ~2;
 
   /* open BIOS file */
-  sprintf (pathname, "%s/BIOS.bin",DEFAULT_PATH);
+  FILE *fp = fopen(BIOS_ROM, "rb");
-  FILE *fp = fopen(pathname, "rb");
   if (fp == NULL) return;
 
   /* read file */

source/gx/osd.h

@@ -25,7 +25,10 @@
 #include "config.h"
 #include "file_mem.h"
 
-#define DEFAULT_PATH "/genplus"
+#define DEFAULT_PATH  "/genplus"
+#define GAMEGENIE_ROM "/genplus/ggenie.bin"
+#define BIOS_ROM      "/genplus/bios.bin"
+
 #ifdef HW_RVL
 #define VERSION "version 1.3.2cW"
 #else

source/shared.h

@@ -26,6 +26,7 @@
 #include "cart_hw.h"
 #include "eeprom.h"
 #include "sram.h"
+#include "ggenie.h"
 #include "svp.h"
 #include "osd.h"
 

source/sound/ym2612.c

@@ -1909,7 +1909,8 @@ void YM2612Update(int length)
 {
   int i;
   int lt,rt;
-  int16 *bufL,*bufR;
+  int16 *bufL = 0;
+  int16 *bufR = 0;
 
   /* Output samples buffers */
   int16 *bufFIR = Fir_Resampler_buffer();

source/system.c

@@ -220,7 +220,7 @@ void system_init (void)
  ****************************************************************/
 void system_reset (void)
 {
-  /* Cartridge Hardware */
+  /* Cartridge Hardware (should be done first !) */
   cart_hw_reset();
 
   /* Genesis Hardware */