improved Pro Action Replay emulation (still not working completely)

added cycle-accurate YM2612 reset handler
some fixes in FIR resampler

source/cart_hw/cart_hw.c

@@ -472,7 +472,7 @@ void cart_hw_reset()
       break;
 
     case TYPE_AR:
-      datel_reset();
+      datel_reset(1);
       break;
 
     case TYPE_SK:

source/cart_hw/datel.c

@@ -64,7 +64,7 @@ void datel_init(void)
   {
     case TYPE_AR:
     {
-      /* internal registers mapped at $0000-$ffff */
+      /* internal registers mapped at $010000-$01ffff */
       m68k_memory_map[0x01].write16 = ar_write_regs;
 
       /* $0000-$7fff mirrored into $8000-$ffff */
@@ -74,18 +74,15 @@ void datel_init(void)
 
     case TYPE_PRO1:
     {
-      /* internal registers mapped at $0000-$ffff */
+      /* internal registers mapped at $010000-$01ffff */
       m68k_memory_map[0x01].write16 = ar_write_regs;
 
-      /* RAM (64k) mapped at $400000-$7fffff */
+      /* RAM (64k) mapped at $420000-$42ffff */
-      for (i=0x40; i<0x80; i++)
+      m68k_memory_map[0x42].base     = action_replay.ram;
-      {
+      m68k_memory_map[0x42].read8    = NULL;
-        m68k_memory_map[i].base     = action_replay.ram;
+      m68k_memory_map[0x42].read16   = NULL;
-        m68k_memory_map[i].read8    = NULL;
+      m68k_memory_map[0x42].write8   = NULL;
-        m68k_memory_map[i].read16   = NULL;
+      m68k_memory_map[0x42].write16  = NULL;
-        m68k_memory_map[i].write8   = NULL;
-        m68k_memory_map[i].write16  = NULL;
-      }
       break;
     }
 
@@ -94,15 +91,12 @@ void datel_init(void)
       /* internal registers mapped at $100000-$10ffff */
       m68k_memory_map[0x10].write16 = ar_write_regs_pro2;
 
-      /* RAM (64k) mapped at $400000-$7fffff */
+      /* RAM (64k) mapped at $600000-$60ffff */
-      for (i=0x40; i<0x80; i++)
+      m68k_memory_map[0x60].base     = action_replay.ram;
-      {
+      m68k_memory_map[0x60].read8    = NULL;
-        m68k_memory_map[i].base     = action_replay.ram;
+      m68k_memory_map[0x60].read16   = NULL;
-        m68k_memory_map[i].read8    = NULL;
+      m68k_memory_map[0x60].write8   = NULL;
-        m68k_memory_map[i].read16   = NULL;
+      m68k_memory_map[0x60].write16  = NULL;
-        m68k_memory_map[i].write8   = NULL;
-        m68k_memory_map[i].write16  = NULL;
-      }
       break;
     }
   }
@@ -119,10 +113,16 @@ void datel_init(void)
 #endif
 }
 
-void datel_reset(void)
+void datel_reset(int hard_reset)
 {
   if (action_replay.enabled)
   {
+    if (hard_reset)
+    {
+      /* clear RAM */
+      memset(action_replay.ram,0,sizeof(action_replay.ram));
+    }
+
     /* reset codes */
     datel_switch(0);
 
@@ -133,33 +133,26 @@ void datel_reset(void)
     memset(action_replay.addr,0,sizeof(action_replay.addr));
 
     /* ROM mapped at $000000-$3fffff */
-    int i;
     switch (action_replay.enabled)
     { 
       case TYPE_AR:   /* 32k ROM */
       case TYPE_PRO2: /* 64k ROM */
       {
-        for (i=0x00; i<0x40; i++)
+        m68k_memory_map[0].base = action_replay.rom;
-        {
-          m68k_memory_map[i].base = action_replay.rom;
-        }
         break;
       }
 
       case TYPE_PRO1: /* 128k ROM */
       {
-        for (i=0x00; i<0x40; i+=2)
+        m68k_memory_map[0].base = action_replay.rom;
-        {
+        m68k_memory_map[1].base = action_replay.rom + 0x10000;
-          m68k_memory_map[i].base   = action_replay.rom;
-          m68k_memory_map[i+1].base = action_replay.rom + 0x10000;
-        }
         break;
       }
     }
   }
 }
 
-void datel_switch(uint8 enable)
+void datel_switch(int enable)
 {
   int i;
   if (enable)
@@ -214,6 +207,13 @@ void datel_switch(uint8 enable)
           *(uint16 *)(work_ram + (action_replay.addr[i]&0xffff)) = action_replay.old[i];
       }
     }
+
+    /* set default Work RAM write handlers */
+    for (i=0xe0; i<0x100; i++)
+    {
+      m68k_memory_map[i].write8   = NULL;
+      m68k_memory_map[i].write16  = NULL;
+    }
   }
 }
 
@@ -280,18 +280,17 @@ static void ar_write_regs(uint32 address, uint32 data)
     action_replay.addr[2] = (action_replay.regs[8]   | ((action_replay.regs[9]   & 0x7f00) << 8)) << 1;
     action_replay.addr[3] = (action_replay.regs[11]  | ((action_replay.regs[12]  & 0x7f00) << 8)) << 1;
 
-    /* Cartridge ROM mapped to $000000-$3fffff */
+    /* Enable Cartridge ROM */
     /* NOTE: codes should be disabled on startup */
-    int i;
+    m68k_memory_map[0].base = cart.rom;
-    for (i=0x00; i<0x40; i++)
+    m68k_memory_map[1].base = cart.rom + ((1<<16) & cart.mask);
-    {
-      m68k_memory_map[i].base = cart.rom + ((i<<16) & cart.mask);
-    }
   }
 }
 
 
 static void ar_write_regs_pro2(uint32 address, uint32 data)
 {
-  /* TODO */
+  /* Enable Cartridge ROM */
+  if (((address & 0xff) == 0x78) && (data == 0xffff))
+    m68k_memory_map[0].base = cart.rom;
 }

source/cart_hw/datel.h

@@ -23,7 +23,7 @@
 #define _DATEL_H_
 
 extern void datel_init(void);
-extern void datel_reset(void);
+extern void datel_reset(int hard_reset);
-extern void datel_switch(uint8 enable);
+extern void datel_switch(int enable);
 
 #endif

source/genesis.c

@@ -42,12 +42,12 @@ void set_softreset(void)
   resetline = (int) ((double) (lines_per_frame - 1) * rand() / (RAND_MAX + 1.0));
 }
 
-void gen_init (void)
+void gen_init(void)
 {
   int i;
 
   /* initialize CPUs */
-  m68k_set_cpu_type (M68K_CPU_TYPE_68000);
+  m68k_set_cpu_type(M68K_CPU_TYPE_68000);
   m68k_init();
   z80_init(0,0,0,z80_irq_callback);
 
@@ -113,33 +113,18 @@ void gen_init (void)
   }
 
   /* VDP */
-  m68k_memory_map[0xc0].read8   = vdp_read_byte;
+  for (i=0xc0; i<0xe0; i+=8)
-  m68k_memory_map[0xc0].read16  = vdp_read_word;
+  {
-  m68k_memory_map[0xc0].write8  = vdp_write_byte;
+    m68k_memory_map[i].read8   = vdp_read_byte;
-  m68k_memory_map[0xc0].write16 = vdp_write_word;
+    m68k_memory_map[i].read16  = vdp_read_word;
-  m68k_memory_map[0xc8].read8   = vdp_read_byte;
+    m68k_memory_map[i].write8  = vdp_write_byte;
-  m68k_memory_map[0xc8].read16  = vdp_read_word;
+    m68k_memory_map[i].write16 = vdp_write_word;
-  m68k_memory_map[0xc8].write8  = vdp_write_byte;
+    zbank_memory_map[i].read   = zbank_read_vdp;
-  m68k_memory_map[0xc8].write16 = vdp_write_word;
+    zbank_memory_map[i].write  = zbank_write_vdp;
-  m68k_memory_map[0xd0].read8   = vdp_read_byte;
+  }
-  m68k_memory_map[0xd0].read16  = vdp_read_word;
-  m68k_memory_map[0xd0].write8  = vdp_write_byte;
-  m68k_memory_map[0xd0].write16 = vdp_write_word;
-  m68k_memory_map[0xd8].read8   = vdp_read_byte;
-  m68k_memory_map[0xd8].read16  = vdp_read_word;
-  m68k_memory_map[0xd8].write8  = vdp_write_byte;
-  m68k_memory_map[0xd8].write16 = vdp_write_word;
-  zbank_memory_map[0xc0].read   = zbank_read_vdp;
-  zbank_memory_map[0xc0].write  = zbank_write_vdp;
-  zbank_memory_map[0xc8].read   = zbank_read_vdp;
-  zbank_memory_map[0xc8].write  = zbank_write_vdp;
-  zbank_memory_map[0xd0].read   = zbank_read_vdp;
-  zbank_memory_map[0xd0].write  = zbank_write_vdp;
-  zbank_memory_map[0xd8].read   = zbank_read_vdp;
-  zbank_memory_map[0xd8].write  = zbank_write_vdp;
 }
 
-void gen_reset (uint32 hard_reset)
+void gen_reset(uint32 hard_reset)
 {
   if (hard_reset)
   {
@@ -152,30 +137,30 @@ void gen_reset (uint32 hard_reset)
     {
       m68k_memory_map[0].base = bios_rom;
     }
+
+    count_m68k  = 0;
+    count_z80   = 0;
+    gen_running = 1;  /* System is running */
+    zreset      = 0;  /* Z80 is reset */
+    zbusreq     = 0;  /* Z80 has control of the Z bus */
+    zbusack     = 1;  /* Z80 is busy using the Z bus */
+    zirq        = 0;  /* No interrupts occuring */
+    zbank       = 0;  /* Assume default bank is $000000-$007FFF */
   }
 
-  gen_running = 1;
   resetline   = -1;
-
 #ifdef NGC
   /* register SOFTRESET */
   SYS_SetResetCallback(set_softreset);
 #endif
 
-  zreset = 0;   /* Z80 is reset */
+  /* reset CPUs */
-  zbusreq = 0;  /* Z80 has control of the Z bus */
+  m68k_pulse_reset();
-  zbusack = 1;  /* Z80 is busy using the Z bus */
+  z80_reset();
-  zirq = 0;     /* No interrupts occuring */
+  fm_reset();
-  zbank = 0;    /* Assume default bank is 000000-007FFF */
-
-  /* Reset CPUs */
-  m68k_pulse_reset ();
-  z80_reset ();
-  YM2612ResetChip();
-  SN76489_Reset();
 }
 
-void gen_shutdown (void)
+void gen_shutdown(void)
 {
   z80_exit();
 }
@@ -183,7 +168,7 @@ void gen_shutdown (void)
 /*-----------------------------------------------------------------------
   Bus controller chip functions                                            
   -----------------------------------------------------------------------*/
-void gen_busreq_w (uint32 state)
+void gen_busreq_w(uint32 state)
 {
   uint32 z80_cycles_to_run;
 
@@ -217,7 +202,7 @@ void gen_busreq_w (uint32 state)
   zbusack = 1 ^ (zbusreq & zreset);
 }
 
-void gen_reset_w (uint32 state)
+void gen_reset_w(uint32 state)
 {
   uint32 z80_cycles_to_run;
 
@@ -247,8 +232,8 @@ void gen_reset_w (uint32 state)
     }
 
     /* Reset Z80 & YM2612 */
-    z80_reset ();
+    z80_reset();
-    YM2612ResetChip();
+    fm_reset();
   }
 
   zreset = state;

source/m68k/m68kconf.h

@@ -160,6 +160,14 @@
 #define M68K_EMULATE_ADDRESS_ERROR  OPT_ON
 
 
+/* If ON, branch instructions will check for infinite loop and
+ * freeze current CPU execution .
+ * Unnecessary checking might be disabled to improve instruction
+ * emulation speed since infinite loops are going to "lock" the CPU
+ * execution anyway.
+ */
+#define M68K_CHECK_INFINITE_LOOP  OPT_OFF
+
 /* Turn ON to enable logging of illegal instruction calls.
  * M68K_LOG_FILEHANDLE must be #defined to a stdio file stream.
  * Turn on M68K_LOG_1010_1111 to log all 1010 and 1111 calls.

source/m68k/m68kcpu.c

@@ -854,6 +854,7 @@ void m68k_run (int cyc)
     if(CPU_STOPPED)
     {
       count_m68k = cyc;
+      REG_PPC = REG_PC;
       return;
     }
 

source/m68k/m68kcpu.h

@@ -606,6 +606,12 @@ extern unsigned int count_m68k;
   #define M68K_DO_LOG_EMU(A)
 #endif
 
+#if M68K_CHECK_INFINITE_LOOP
+  #define m68ki_check_infinite_loop() if(REG_PC == REG_PPC) USE_ALL_CYCLES()
+#else
+  #define m68ki_check_infinite_loop()
+#endif /* M68K_CHECK_INFINITE_LOOP */
+
 
 
 /* -------------------------- EA / Operand Access ------------------------- */

source/m68k/m68kops.c

@@ -8067,8 +8067,7 @@ static void m68k_op_bra_8(void)
 {
   m68ki_trace_t0();           /* auto-disable (see m68kcpu.h) */
   m68ki_branch_8(MASK_OUT_ABOVE_8(REG_IR));
-  if(REG_PC == REG_PPC)
+  m68ki_check_infinite_loop();  /* auto-disable (see m68kcpu.h) */
-    USE_ALL_CYCLES();
 }
 
 
@@ -8078,8 +8077,7 @@ static void m68k_op_bra_16(void)
   REG_PC -= 2;
   m68ki_trace_t0();         /* auto-disable (see m68kcpu.h) */
   m68ki_branch_16(offset);
-  if(REG_PC == REG_PPC)
+  m68ki_check_infinite_loop();  /* auto-disable (see m68kcpu.h) */
-    USE_ALL_CYCLES();
 }
 
 
@@ -8091,16 +8089,14 @@ static void m68k_op_bra_32(void)
     REG_PC -= 4;
     m68ki_trace_t0();         /* auto-disable (see m68kcpu.h) */
     m68ki_branch_32(offset);
-    if(REG_PC == REG_PPC)
+    m68ki_check_infinite_loop();  /* auto-disable (see m68kcpu.h) */
-      USE_ALL_CYCLES();
     return;
   }
   else
   {
     m68ki_trace_t0();           /* auto-disable (see m68kcpu.h) */
     m68ki_branch_8(MASK_OUT_ABOVE_8(REG_IR));
-    if(REG_PC == REG_PPC)
+    m68ki_check_infinite_loop();  /* auto-disable (see m68kcpu.h) */
-      USE_ALL_CYCLES();
   }
 }
 
@@ -16542,8 +16538,7 @@ static void m68k_op_jmp_32_ai(void)
 {
   m68ki_jump(EA_AY_AI_32());
   m68ki_trace_t0();           /* auto-disable (see m68kcpu.h) */
-  if(REG_PC == REG_PPC)
+  m68ki_check_infinite_loop();  /* auto-disable (see m68kcpu.h) */
-    USE_ALL_CYCLES();
 }
 
 
@@ -16551,8 +16546,7 @@ static void m68k_op_jmp_32_di(void)
 {
   m68ki_jump(EA_AY_DI_32());
   m68ki_trace_t0();           /* auto-disable (see m68kcpu.h) */
-  if(REG_PC == REG_PPC)
+  m68ki_check_infinite_loop();  /* auto-disable (see m68kcpu.h) */
-    USE_ALL_CYCLES();
 }
 
 
@@ -16560,8 +16554,7 @@ static void m68k_op_jmp_32_ix(void)
 {
   m68ki_jump(EA_AY_IX_32());
   m68ki_trace_t0();           /* auto-disable (see m68kcpu.h) */
-  if(REG_PC == REG_PPC)
+  m68ki_check_infinite_loop();  /* auto-disable (see m68kcpu.h) */
-    USE_ALL_CYCLES();
 }
 
 
@@ -16569,8 +16562,7 @@ static void m68k_op_jmp_32_aw(void)
 {
   m68ki_jump(EA_AW_32());
   m68ki_trace_t0();           /* auto-disable (see m68kcpu.h) */
-  if(REG_PC == REG_PPC)
+  m68ki_check_infinite_loop();  /* auto-disable (see m68kcpu.h) */
-    USE_ALL_CYCLES();
 }
 
 
@@ -16578,8 +16570,7 @@ static void m68k_op_jmp_32_al(void)
 {
   m68ki_jump(EA_AL_32());
   m68ki_trace_t0();           /* auto-disable (see m68kcpu.h) */
-  if(REG_PC == REG_PPC)
+  m68ki_check_infinite_loop();  /* auto-disable (see m68kcpu.h) */
-    USE_ALL_CYCLES();
 }
 
 
@@ -16587,8 +16578,7 @@ static void m68k_op_jmp_32_pcdi(void)
 {
   m68ki_jump(EA_PCDI_32());
   m68ki_trace_t0();           /* auto-disable (see m68kcpu.h) */
-  if(REG_PC == REG_PPC)
+  m68ki_check_infinite_loop();  /* auto-disable (see m68kcpu.h) */
-    USE_ALL_CYCLES();
 }
 
 
@@ -16596,8 +16586,7 @@ static void m68k_op_jmp_32_pcix(void)
 {
   m68ki_jump(EA_PCIX_32());
   m68ki_trace_t0();           /* auto-disable (see m68kcpu.h) */
-  if(REG_PC == REG_PPC)
+  m68ki_check_infinite_loop();  /* auto-disable (see m68kcpu.h) */
-    USE_ALL_CYCLES();
 }
 
 

source/sound/Fir_Resampler.c

@@ -76,11 +76,10 @@ static int available( unsigned long input_count )
 int Fir_Resampler_initialize( int new_size )
 {
   buffer = (sample_t *) realloc( buffer, (new_size + WRITE_OFFSET) * sizeof (sample_t) );
+  write_pos = 0;
   if ( !buffer && new_size ) return 0;
   buffer_size = new_size + WRITE_OFFSET;
-  write_pos = 0;
   res       = 1;
-  imp_phase = 0;
   skip_bits = 0;
   step      = STEREO;
   ratio     = 1.0;
@@ -206,28 +205,27 @@ int Fir_Resampler_read( sample_t** out, unsigned long count )
   sample_t const* imp = impulses [imp_phase];
   int remain = res - imp_phase;
   int n;
+  int pt0,pt1;
+  sample_t* i;
+  unsigned long l,r;
 
   if ( end_pos - in >= WIDTH * STEREO )
   {
     end_pos -= WIDTH * STEREO;
     do
     {
-      count--;
-      
       /* accumulate in extended precision */
-      unsigned long l = 0;
+      l = 0;
-      unsigned long r = 0;
+      r = 0;
 
-      const sample_t* i = in;
+      i = in;
-      if ( count < 0 )
-        break;
 
       for ( n = WIDTH / 2; n; --n )
       {
-        int pt0 = imp [0];
+        pt0 = imp [0];
         l += pt0 * i [0];
         r += pt0 * i [1];
-        int pt1 = imp [1];
+        pt1 = imp [1];
         imp += 2;
         l += pt1 * i [2];
         r += pt1 * i [3];
@@ -253,7 +251,7 @@ int Fir_Resampler_read( sample_t** out, unsigned long count )
       *out_l++ = (sample_t) l;
       *out_r++ = (sample_t) r;
     }
-    while ( in <= end_pos );
+    while ( (in <= end_pos) && (--count > 0) );
   }
 
   imp_phase = res - remain;

source/sound/sound.c

@@ -40,7 +40,7 @@ static inline int psg_sample_cnt(uint8 z80)
   else return ((count_m68k / m68cycles_per_sample[1]) - snd.psg.pos);
 }
 
-/* update FM samples */
+/* run FM chip for n samples */
 static inline void fm_update(int cnt)
 {
   if (cnt > 0)
@@ -50,7 +50,7 @@ static inline void fm_update(int cnt)
   }
 }
 
-/* update PSG samples */
+/* run PSG chip for n samples */
 static inline void psg_update(int cnt)
 {
   if (cnt > 0)
@@ -60,6 +60,7 @@ static inline void psg_update(int cnt)
   }
 }
 
+/* initialize sound chips emulation */
 void sound_init(int rate)
 {
   double vclk = (vdp_pal ? (double)CLOCK_PAL : (double)CLOCK_NTSC) / 7.0;  /* 68000 and YM2612 clock */
@@ -96,6 +97,13 @@ void sound_update(int fm_len, int psg_len)
   snd.psg.pos  = 0;
 }
 
+/* reset FM chip */
+void fm_reset(void)
+{
+  fm_update(fm_sample_cnt(0));
+  YM2612ResetChip();
+}
+
 /* write FM chip */
 void fm_write(unsigned int cpu, unsigned int address, unsigned int data)
 {
@@ -110,8 +118,7 @@ unsigned int fm_read(unsigned int cpu, unsigned int address)
   return YM2612Read();
 }
 
-
+/* write PSG chip */
-/* PSG write */
 void psg_write(unsigned int cpu, unsigned int data)
 {
   psg_update(psg_sample_cnt(cpu));

source/sound/sound.h

@@ -27,6 +27,7 @@
 /* Function prototypes */
 extern void sound_init(int rate);
 extern void sound_update(int fm_len, int psg_len);
+extern void fm_reset(void);
 extern void fm_write(unsigned int cpu, unsigned int  address, unsigned int  data);
 extern unsigned int fm_read(unsigned int  cpu, unsigned int  address);
 extern void psg_write(unsigned int  cpu, unsigned int  data);

source/system.c

@@ -78,7 +78,7 @@ void audio_update (int size)
   /* resampling */
   if (config.hq_fm)
   {
-    int len = Fir_Resampler_input_needed(size * 2);
+    int len = Fir_Resampler_input_needed(size << 1);
     sound_update(len >> 1,size);
     Fir_Resampler_write(len);
     Fir_Resampler_read(fm,size);
@@ -209,9 +209,9 @@ void audio_shutdown(void)
 void system_init (void)
 {
   /* Genesis hardware */
-  gen_init ();
+  gen_init();
-  vdp_init ();
+  vdp_init();
-  render_init ();
+  render_init();
   io_init();
 
   /* Cartridge hardware */
@@ -227,9 +227,10 @@ void system_reset (void)
   cart_hw_reset();
 
   /* Genesis hardware */
-  gen_reset (1); 
+  gen_reset(1); 
-  vdp_reset ();
+  SN76489_Reset();
-  render_reset ();
+  vdp_reset();
+  render_reset();
   io_reset();
 
   /* Clear Sound Buffers */
@@ -321,6 +322,10 @@ int system_frame (int do_skip)
       /* wait for RESET button to be released */
       while (SYS_ResetButtonDown());
 #endif
+      /* Pro Action Replay (switch at "Trainer" position) */
+      if (config.lock_on == TYPE_AR)
+        datel_reset(0);
+
       gen_reset(0);
     }
 

source/vdp.c

@@ -211,7 +211,7 @@ void vdp_reset(void)
   bitmap.viewport.ow = 224;
 
   /* reset border area */
-  bitmap.viewport.x = (reg[12] & 1) ? 16 : 12;
+  bitmap.viewport.x = config.overscan ? ((reg[12] & 1) ? 16 : 12) : 0;
   bitmap.viewport.y = config.overscan ? (vdp_pal ? 32 : 8) : 0;
   bitmap.viewport.changed = 1;
 
@@ -245,7 +245,7 @@ void vdp_restore(uint8 *vdp_regs)
   hctab = (reg[12] & 1) ? cycle2hc40 : cycle2hc32;
 
   /* reinitialize overscan area */
-  bitmap.viewport.x = (reg[12] & 1) ? 16 : 12;
+  bitmap.viewport.x = config.overscan ? ((reg[12] & 1) ? 16 : 12) : 0;
   bitmap.viewport.y = config.overscan ? (((reg[1] & 8) ? 0 : 8) + (vdp_pal ? 24 : 0)) : 0;
   bitmap.viewport.changed = 1;
 
@@ -685,10 +685,7 @@ static inline void reg_w(unsigned int r, unsigned int d)
         /* update viewport */
         bitmap.viewport.changed = 1;
         bitmap.viewport.h = (d & 8) ? 240 : 224;
-        if (config.overscan)
+        if (config.overscan) bitmap.viewport.y = ((vdp_pal ? 288 : 240) - bitmap.viewport.h) / 2;
-        {
-          bitmap.viewport.y = ((vdp_pal ? 288 : 240) - bitmap.viewport.h) / 2;
-        }
 
         /* update VC table */
         if (vdp_pal) vctab = (d & 8) ? vc_pal_240 : vc_pal_224;