fixed broken YM2612 initial state, rewrote SSG-EG implementation (OK), reverted some menu changes

2024-11-04 18:05:06 +01:00 · 2009-02-26 17:24:53 +00:00 · 2009-02-26 17:24:53 +00:00 · a857fb3990
commit a857fb3990
parent b75d86889e
3 changed files with 92 additions and 74 deletions
--- a/history.txt
+++ b/history.txt
@ -6,8 +6,8 @@ Genesis Plus GX 1.3.2 (??/??/????) (Eke-Eke)
 ------

 * modified SN76489 cut-off frequency
-* removed outdated Gens YM2612 core
-* improved MAME YM2612 core accuracy: SSG-EG support, CSM Mode (based upon last Nemesis tests on real hardware)
+* removed old Gens YM2612 core support
+* improved MAME YM2612 core accuracy: SSG-EG mode, CSM mode (based on Nemesis real hardware's last tests)
 * fixed YM2612 context restore
 * modified sound update engine to fix synchronization issues (see below)
 * various code cleanup
--- a/source/ngc/gui/menu.c
+++ b/source/ngc/gui/menu.c
@ -152,15 +152,29 @@ void drawmenu (char items[][25], int maxitems, int selected)
  ypos = (226 - (fheight * maxitems)) >> 1;
  ypos += 130;

-  DrawMenu (main_buttons, 6, selected);
+  /*DrawMenu (main_buttons, 6, selected);*/
+  /* reset texture data */
+  png_texture texture;
+  memset(&texture,0,sizeof(png_texture));

-  /*WriteCentre (134, menutitle);
+  /* draw background items */
+  ClearScreen ((GXColor)BLACK);
+  OpenPNGFromMemory(&texture, Background_main);
+  DrawTexture(&texture, (640-texture.width)/2, (480-124-texture.height)/2,  texture.width, texture.height);
+  OpenPNGFromMemory(&texture, Banner_bottom);
+  DrawTexture(&texture, 640-texture.width, 480-texture.height, texture.width, texture.height);
+  OpenPNGFromMemory(&texture, Banner_top);
+  DrawTexture(&texture, 640-texture.width, 0, texture.width, texture.height);
+  OpenPNGFromMemory(&texture, Main_logo);
+  DrawTexture(&texture, 444, 28, 176, 48);
+
+  WriteCentre (134, menutitle);

  for (i = 0; i < maxitems; i++)
  {
      if (i == selected) WriteCentre_HL (i * fheight + ypos, (char *) items[i]);
      else WriteCentre (i * fheight + ypos, (char *) items[i]);
-  }*/
+  }

  SetScreen ();
 }
--- a/source/sound/fm.c
+++ b/source/sound/fm.c
@ -25,8 +25,8 @@
 **  - fixed YM2612 initial values (after the reset)
 **  - implemented correct Detune overflow (Ariel, Comix Zone, Shaq Fu, Spiderman & many others)
 **  - implemented correct CSM mode support
-**  - rewrote SSG-EG emulation (Asterix, Bubba'n Six & many others)
-**  - modified some EG rates
+**  - implemented correct SSG-EG support (Asterix, Beavis&Butthead, Bubba'n Six & many others)
+**  - adjusted some EG rates
 **  - modified address/data port behavior
 **

@ -632,7 +632,7 @@ INLINE void FM_KEYON(FM_CH *CH , int s )

    if ((SLOT->ar + SLOT->ksr) < 94 /*32+62*/)
    {
-      SLOT->state = EG_ATT;  /* phase -> Attack */
+      SLOT->state = (SLOT->volume <= MIN_ATT_INDEX) ? ((SLOT->sl == MIN_ATT_INDEX) ? EG_SUS : EG_DEC) : EG_ATT;
    }
    else
    {
@ -645,7 +645,7 @@ INLINE void FM_KEYON(FM_CH *CH , int s )

    /* recalculate EG output */
    if ((SLOT->ssg&0x08) && (SLOT->ssgn ^ (SLOT->ssg&0x04)))
-      SLOT->vol_out = ((UINT32)SLOT->volume ^ 0x1FF) + 1 + SLOT->tl; /* SSG-EG Output Inversion */
+      SLOT->vol_out = ((UINT32)(0x200 - SLOT->volume) & MAX_ATT_INDEX) + SLOT->tl;
    else
      SLOT->vol_out = (UINT32)SLOT->volume + SLOT->tl;
  }
@ -690,7 +690,7 @@ INLINE void FM_KEYON_CSM(FM_CH *CH , int s )

    if ((SLOT->ar + SLOT->ksr) < 94 /*32+62*/)
    {
-      SLOT->state = EG_ATT;  /* phase -> Attack */
+      SLOT->state = (SLOT->volume <= MIN_ATT_INDEX) ? ((SLOT->sl == MIN_ATT_INDEX) ? EG_SUS : EG_DEC) : EG_ATT;
    }
    else
    {
@ -703,7 +703,7 @@ INLINE void FM_KEYON_CSM(FM_CH *CH , int s )

    /* recalculate EG output */
    if ((SLOT->ssg&0x08) && (SLOT->ssgn ^ (SLOT->ssg&0x04)))
-      SLOT->vol_out = ((UINT32)SLOT->volume ^ 0x1FF) + 1 + SLOT->tl; /* SSG-EG Output Inversion */
+      SLOT->vol_out = ((UINT32)(0x200 - SLOT->volume) & MAX_ATT_INDEX) + SLOT->tl;
    else
      SLOT->vol_out = (UINT32)SLOT->volume + SLOT->tl;
  }
@ -869,7 +869,7 @@ INLINE void set_tl(FM_CH *CH,FM_SLOT *SLOT , int v)

  /* recalculate EG output */
  if ((SLOT->ssg&0x08) && (SLOT->ssgn ^ (SLOT->ssg&0x04)) && (SLOT->state > EG_REL))
-    SLOT->vol_out = ((UINT32)SLOT->volume ^ 0x1FF) + 1 + SLOT->tl; /* SSG-EG Output Inversion */
+    SLOT->vol_out = ((UINT32)(0x200 - SLOT->volume) & MAX_ATT_INDEX) + SLOT->tl;
  else
    SLOT->vol_out = (UINT32)SLOT->volume + SLOT->tl;
 }
@ -1028,7 +1028,7 @@ INLINE void advance_eg_channel(FM_SLOT *SLOT)

          /* recalculate EG output */
          if ((SLOT->ssg&0x08) && (SLOT->ssgn ^ (SLOT->ssg&0x04)))  /* SSG-EG Output Inversion */
-            SLOT->vol_out = ((UINT32)SLOT->volume ^ 0x1FF) + 1 + SLOT->tl;
+            SLOT->vol_out = ((UINT32)(0x200 - SLOT->volume) & MAX_ATT_INDEX) + SLOT->tl;
          else
            SLOT->vol_out = (UINT32)SLOT->volume + SLOT->tl;
        }
@ -1042,13 +1042,15 @@ INLINE void advance_eg_channel(FM_SLOT *SLOT)
          {
            /* update attenuation level */
            if (SLOT->volume < 0x200)
+            {
              SLOT->volume += 4 * eg_inc[SLOT->eg_sel_d1r + ((ym2612.OPN.eg_cnt>>SLOT->eg_sh_d1r)&7)];

-            /* recalculate EG output */
-            if (SLOT->ssgn ^ (SLOT->ssg&0x04))   /* SSG-EG Output Inversion */
-              SLOT->vol_out = ((UINT32)SLOT->volume ^ 0x1FF) + 1 + SLOT->tl;
-            else
-              SLOT->vol_out = (UINT32)SLOT->volume + SLOT->tl;
+              /* recalculate EG output */
+              if (SLOT->ssgn ^ (SLOT->ssg&0x04))   /* SSG-EG Output Inversion */
+                SLOT->vol_out = ((UINT32)(0x200 - SLOT->volume) & MAX_ATT_INDEX) + SLOT->tl;
+              else
+                SLOT->vol_out = (UINT32)SLOT->volume + SLOT->tl;
+            }
          }
          else
          {
@ -1073,13 +1075,15 @@ INLINE void advance_eg_channel(FM_SLOT *SLOT)
          {
            /* update attenuation level */
            if (SLOT->volume < 0x200)
+            {
              SLOT->volume += 4 * eg_inc[SLOT->eg_sel_d2r + ((ym2612.OPN.eg_cnt>>SLOT->eg_sh_d2r)&7)];

-            /* recalculate EG output */
-            if (SLOT->ssgn ^ (SLOT->ssg&0x04))   /* SSG-EG Output Inversion */
-              SLOT->vol_out = ((UINT32)SLOT->volume ^ 0x1FF) + 1 + SLOT->tl;
-            else
-              SLOT->vol_out = (UINT32)SLOT->volume + SLOT->tl;
+              /* recalculate EG output */
+              if (SLOT->ssgn ^ (SLOT->ssg&0x04))   /* SSG-EG Output Inversion */
+                SLOT->vol_out = ((UINT32)(0x200 - SLOT->volume) & MAX_ATT_INDEX) + SLOT->tl;
+              else
+                SLOT->vol_out = (UINT32)SLOT->volume + SLOT->tl;
+            }
          }
          else
          {
@ -1106,6 +1110,13 @@ INLINE void advance_eg_channel(FM_SLOT *SLOT)
            /* update attenuation level */
            if (SLOT->volume < 0x200)
              SLOT->volume += 4 * eg_inc[SLOT->eg_sel_rr + ((ym2612.OPN.eg_cnt>>SLOT->eg_sh_rr)&7)];
+
+            /* check phase transition */
+            if (SLOT->volume >= 0x200)
+            {
+              SLOT->volume = MAX_ATT_INDEX;
+              SLOT->state = EG_OFF;
+            }
          }
          else
          {
@ -1132,64 +1143,57 @@ INLINE void advance_eg_channel(FM_SLOT *SLOT)
  } while (i);
 }

-
+/* SSG-EG update process */
+/* The behavior is based upon Nemesis tests on real hardware */
+/* This is actually executed before each samples */
 INLINE void update_ssg_eg_channel(FM_SLOT *SLOT)
 {
  unsigned int i = 4; /* four operators per channel */
-  int update_out = 0;

  do
  {
-    /* check SSG-EG state */
-    if ((SLOT->ssg & 0x08) && (SLOT->volume >= 0x200))
+    /* detect SSG-EG transition */
+    /* this is not required during release phase as the attenuation is set to MAX and output invert flag is not used */
+    /* if an Attack Phase is programmed, inversion can occur on each sample */
+    if ((SLOT->ssg & 0x08) && (SLOT->volume >= 0x200) && (SLOT->state > EG_REL))
    {
-      /* swap Invert Output flag if required */
-      /* if HOLD bit is set, verify we didn't already swapped once */
-      if ((SLOT->ssg & 0x02) && (!(SLOT->ssg & 0x01) || !(SLOT->ssgn&4)))
+      if (SLOT->ssg & 0x01)  /* bit 0 = hold SSG-EG */
      {
-        SLOT->ssgn ^= 4;
-        update_out = 1;
+        /* set inversion flag */
+        if ((SLOT->ssg & 0x02) && !SLOT->ssgn)
+          SLOT->ssgn = 4;
+
+        /* force attenuation level */
+        if (!(SLOT->ssgn ^ (SLOT->ssg & 0x04)))
+          SLOT->volume  = MAX_ATT_INDEX;
      }
-
-      /* output is not alternated and not hold */ 
-      if (!(SLOT->ssg & 0x02) && !(SLOT->ssg & 0x01))
-        SLOT->phase = 0;  /* reset Phase Generator */
-
-      /* update EG phase */
-      if (SLOT->state < EG_ATT)
+      else  /* loop SSG-EG */
      {
-        if ((SLOT->state != EG_REL) && (!SLOT->ssg&0x01))
+        /* toggle output inversion flag or reset Phase Generator */
+        if (SLOT->ssg & 0x02) SLOT->ssgn ^= 4;
+        else SLOT->phase = 0;
+
+        /* same as Key ON */
+        if (SLOT->state != EG_ATT)
        {
-          /* same as Key ON */
          if ((SLOT->ar + SLOT->ksr) < 94 /*32+62*/)
          {
-            SLOT->state = EG_ATT;   /* phase -> Attack */
+            SLOT->state = (SLOT->volume <= MIN_ATT_INDEX) ? ((SLOT->sl == MIN_ATT_INDEX) ? EG_SUS : EG_DEC) : EG_ATT;
          }
          else
          {
-            /* Attack Rate is maximal: directly switch to Decay */
+            /* Attack Rate is maximal: directly switch to Decay or Substain */
            SLOT->volume = MIN_ATT_INDEX;
-            SLOT->state = (SLOT->sl == MIN_ATT_INDEX) ? EG_SUS : EG_DEC; /* special case where SL=0 */
-            update_out = 1;
+            SLOT->state = (SLOT->sl == MIN_ATT_INDEX) ? EG_SUS : EG_DEC;
          }
        }
-        else if (SLOT->state == EG_REL || (!(SLOT->ssgn ^ (SLOT->ssg & 0x04))))
-        {
-          SLOT->volume = MAX_ATT_INDEX;
-          update_out = 1;
-        }
      }

      /* recalculate EG output */
-      if (update_out)
-      {
-        update_out = 0;
-
-        if ((SLOT->state > EG_REL) && (SLOT->ssgn ^ (SLOT->ssg&0x04)))
-          SLOT->vol_out = ((UINT32)SLOT->volume ^ 0x1FF) + 1 + SLOT->tl;
-        else
-          SLOT->vol_out = (UINT32)SLOT->volume + SLOT->tl;
-      }
+      if (SLOT->ssgn ^ (SLOT->ssg&0x04))
+        SLOT->vol_out = ((UINT32)(0x200 - SLOT->volume) & MAX_ATT_INDEX) + SLOT->tl;
+      else
+        SLOT->vol_out = (UINT32)SLOT->volume + SLOT->tl;
    }

    /* next slot */
@ -1198,7 +1202,6 @@ INLINE void update_ssg_eg_channel(FM_SLOT *SLOT)
   } while (i);
 }

-
 #define volume_calc(OP) ((OP)->vol_out + (AM & (OP)->AMmask))

 INLINE void update_phase_lfo_slot(FM_SLOT *SLOT , INT32 pms, UINT32 block_fnum)
@ -1717,10 +1720,13 @@ static void OPNWriteReg(int r, int v)
      SLOT->ssg  = v&0x0f;

      /* recalculate EG output */
-      if ((SLOT->ssg&0x08) && (SLOT->ssgn ^ (SLOT->ssg&0x04)) && (SLOT->state > EG_REL))
-        SLOT->vol_out = ((UINT32)SLOT->volume ^ 0x1FF) + 1 + SLOT->tl; /* SSG-EG Output Inversion */
-      else
-        SLOT->vol_out = (UINT32)SLOT->volume + SLOT->tl;
+      if (SLOT->state > EG_REL)
+      {
+        if ((SLOT->ssg&0x08) && (SLOT->ssgn ^ (SLOT->ssg&0x04)))
+          SLOT->vol_out = ((UINT32)(0x200 - SLOT->volume) & MAX_ATT_INDEX) + SLOT->tl;
+        else
+          SLOT->vol_out = (UINT32)SLOT->volume + SLOT->tl;
+      }

      /* SSG-EG envelope shapes :

@ -1730,11 +1736,11 @@ static void OPNWriteReg(int r, int v)
      1 0 0 1  \___

      1 0 1 0  \/\/
-            ___
+                ___
      1 0 1 1  \

      1 1 0 0  ////
-            ___
+                ___
      1 1 0 1  /

      1 1 1 0  /\/\
@ -1919,10 +1925,10 @@ void YM2612UpdateOne(int **buffer, int length)
    update_ssg_eg_channel(&ym2612.CH[5].SLOT[SLOT1]);

    /* advance envelope generator */
-    ym2612.OPN.eg_timer += ym2612.OPN.eg_timer_add;
-    while (ym2612.OPN.eg_timer >= ym2612.OPN.eg_timer_overflow)
+    ym2612.OPN.eg_timer ++;
+    if (ym2612.OPN.eg_timer == 3)
    {
-      ym2612.OPN.eg_timer -= ym2612.OPN.eg_timer_overflow;
+      ym2612.OPN.eg_timer = 0;
      ym2612.OPN.eg_cnt++;

      advance_eg_channel(&ym2612.CH[0].SLOT[SLOT1]);
@ -2030,10 +2036,8 @@ int YM2612ResetChip(void)
  reset_channels(&ym2612.CH[0] , 6 );
  for(i = 0xb6 ; i >= 0xb4 ; i-- )
  {
-    /*OPNWriteReg(i      ,0xc0);
-    OPNWriteReg(i|0x100,0xc0);*/
-    OPNWriteReg(i      ,0);
-    OPNWriteReg(i|0x100,0);
+    OPNWriteReg(i      ,0xc0);
+    OPNWriteReg(i|0x100,0xc0);
  }
  for(i = 0xb2 ; i >= 0x30 ; i-- )
  {
@ -2056,7 +2060,7 @@ void YM2612Write(unsigned int a, unsigned int v)
 {
  v &= 0xff;  /* adjust to 8 bit bus */

-  switch( a&3 )
+  switch( a )
  {
    case 0:  /* address port 0 */
      ym2612.OPN.ST.address = v;