V5.1: 03-Jan-2022 by wavemotion-dave

* MSX1 emulation now supports some of the common Mappers - some of the 128K games work but you'll probably have to turn off Vert Sync and turn on Frame Skip to get it to run full speed.
wavemotion-dave · Jan 3, 2022 · bffb1a3 · bffb1a3
1 parent 9cab4d7
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Showing 10 changed files with 509 additions and 92 deletions.
diff --git a/ColecoDS.nds b/ColecoDS.nds
diff --git a/Makefile b/Makefile
@@ -9,7 +9,7 @@ include $(DEVKITARM)/ds_rules
 
 export TARGET		:=	ColecoDS
 export TOPDIR		:=	$(CURDIR)
-export VERSION		:=  5.0
+export VERSION		:=  5.1
 
 ICON 		:= -b $(CURDIR)/logo.bmp "ColecoDS $(VERSION);wavemotion-dave;https://github.com/wavemotion-dave/ColecoDS" 
 

diff --git a/README.md b/README.md
@@ -132,6 +132,11 @@ would personally try them:
 
 Versions :
 -----------------------
+V5.1: 03-Jan-2022 by wavemotion-dave
+* MSX1 emulation now supports some of the common Mappers - some of 
+  the 128K games work but you'll probably have to turn off Vert Sync
+  and turn on Frame Skip to get it to run full speed.
+
 V5.0: 02-Jan-2022 by wavemotion-dave
 * MSX1 game support up to 32K Standard Loader (.msx format)
 * New 3/4 Frameskip (show 3 of 4 frames) to help DS-LITE

diff --git a/arm9/gfx_data/pdev_bg0.png b/arm9/gfx_data/pdev_bg0.png
diff --git a/arm9/source/colecoDS.h b/arm9/source/colecoDS.h
@@ -5,7 +5,7 @@
 #include <string.h>
 #include "cpu/z80/drz80/Z80_interface.h"
 
-#define VERSIONCLDS "5.0"
+#define VERSIONCLDS "5.1"
 
 //#define DEBUG_Z80   YES
 

diff --git a/arm9/source/colecomngt.c b/arm9/source/colecomngt.c
diff --git a/arm9/source/colecomngt.h b/arm9/source/colecomngt.h
@@ -8,6 +8,21 @@
 #define IMAGE_VERIFY_FAIL 0X01
 #define IMAGE_VERIFY_PASS 0x02
 
+extern u8 mapperType;
+extern u8 mapperMask;
+
+#define KON8        0
+#define ASC8        1
+#define SCC8        2
+#define ASC16       3
+
+#define MAX_MAPPERS 4
+
+extern u8 bROMInSlot[];
+extern u8 bRAMInSlot[];
+extern u8 PortA8;
+extern u8 *Slot1ROMPtr[];
+
 extern u8 VR;                           // Sound and VDP register storage
 
 extern u8 JoyMode;                      // Joystick / Paddle management

diff --git a/arm9/source/cpu/sn76496/Fake_AY.c b/arm9/source/cpu/sn76496/Fake_AY.c
@@ -13,6 +13,16 @@
 // The 'Fake' AY handler simply turns AY sound register access into corresponding
 // SN sound chip calls. There is some loss of fidelity and we have to handle the
 // volume envelopes in a very crude way... but it works and is good enough for now.
+//
+// The AY register map is as follows:
+// Reg      Description
+// 0-5      Tone generator control for channels A,B,C
+// 6        Noise generator control
+// 7        Mixer control-I/O enable
+// 8-10     Amplitude control for channels A,B,C
+// 11-12    Envelope generator period
+// 13       Envelope generator shape
+// 14-15    I/O ports A & B (MSX Joystick mapped in here - otherwise unused)
 // ------------------------------------------------------------------------------------
 
 #include <nds.h>
@@ -78,12 +88,15 @@ void FakeAY_Loop(void)
 
     if (envelope_period == 0) return;
 
-    if (++delay > ((envelope_period)+1))
+    if (++delay > ((envelope_period>>2)+1))
     {
         delay = 0;
-        u8 shape=0;
-        shape = ay_reg[0x0D] & 0x0F;
-        if ((ay_reg[0x08] & 0x20) && (!(ay_reg[0x07] & 0x01)))
+        u8 shape = ay_reg[0x0D] & 0x0F;
+
+        // ---------------------------------------------------------------
+        // If Envelope is enabled for Channel A and Channel is enabled...
+        // ---------------------------------------------------------------
+        if ((ay_reg[0x08] & 0x20) && (!(ay_reg[0x07] & 0x01)) && channel_a_enable)
         {
             u8 vol = Envelopes[shape][a_idx]; 
             if (++a_idx > 31)
@@ -93,7 +106,10 @@ void FakeAY_Loop(void)
             sn76496W(0x90 | vol, &aycol);
         }
 
-        if ((ay_reg[0x09] & 0x20) && (!(ay_reg[0x07] & 0x02)))
+        // ---------------------------------------------------------------
+        // If Envelope is enabled for Channel B and Channel is enabled...
+        // ---------------------------------------------------------------
+        if ((ay_reg[0x09] & 0x20) && (!(ay_reg[0x07] & 0x02)) && channel_b_enable)
         {
             u8 vol = Envelopes[shape][b_idx]; 
             if (++b_idx > 31)
@@ -103,7 +119,10 @@ void FakeAY_Loop(void)
             sn76496W(0xB0 | vol, &aycol);
         }
 
-        if ((ay_reg[0x0A] & 0x20) && (!(ay_reg[0x07] & 0x04)))
+        // ---------------------------------------------------------------
+        // If Envelope is enabled for Channel C and Channel is enabled...
+        // ---------------------------------------------------------------
+        if ((ay_reg[0x0A] & 0x20) && (!(ay_reg[0x07] & 0x04)) && channel_c_enable)
         {
             u8 vol = Envelopes[shape][c_idx]; 
             if (++c_idx > 31)
@@ -138,7 +157,7 @@ u8 FakeAY_ReadData(void)
 // ------------------------------------------------------------------
 void UpdateNoiseAY(void)
 {
-      // Noise Channel - we turn it on if the noise channel is enable along with the channel's volume not zero...
+      // Noise Channel - we turn it on if the noise channel is enabled along with the channel's volume not zero...
       if ( (!(ay_reg[0x07] & 0x08) && (ay_reg[0x08] != 0) && channel_a_enable) || 
            (!(ay_reg[0x07] & 0x10) && (ay_reg[0x09] != 0) && channel_b_enable) || 
            (!(ay_reg[0x07] & 0x20) && (ay_reg[0x0A] != 0) && channel_c_enable) )
@@ -149,9 +168,12 @@ void UpdateNoiseAY(void)
               if (noise_period > 16) sn76496W(0xE2, &aycol);       // E2 is the lowest frequency (highest period)
               else if (noise_period > 8) sn76496W(0xE1, &aycol);   // E1 is the middle frequency (middle period)
               else sn76496W(0xE0, &aycol);                         // E0 is the highest frequency (lowest period)
+
+              // Now output the noise for the first channel it's enbled on...
               if (!(ay_reg[0x07] & 0x08) && (ay_reg[0x08] != 0) && channel_a_enable) sn76496W(0xF0 | Volumes[ay_reg[0x08]], &aycol);
-              if (!(ay_reg[0x07] & 0x10) && (ay_reg[0x09] != 0) && channel_b_enable) sn76496W(0xF0 | Volumes[ay_reg[0x09]], &aycol);
-              if (!(ay_reg[0x07] & 0x20) && (ay_reg[0x0A] != 0) && channel_c_enable) sn76496W(0xF0 | Volumes[ay_reg[0x0A]], &aycol);
+              else if (!(ay_reg[0x07] & 0x10) && (ay_reg[0x09] != 0) && channel_b_enable) sn76496W(0xF0 | Volumes[ay_reg[0x09]], &aycol);
+              else if (!(ay_reg[0x07] & 0x20) && (ay_reg[0x0A] != 0) && channel_c_enable) sn76496W(0xF0 | Volumes[ay_reg[0x0A]], &aycol);
+              else sn76496W(0xFF, &aycol);
           }
       }
       else
@@ -275,7 +297,7 @@ void FakeAY_WriteData(u8 Value)
                   if (channel_b_enable)
                   {
                       channel_b_enable = 0;
-                      sn76496W(0xB0 | 0x0F, &aycol);
+                      sn76496W(0xB0 | 0x0F, &aycol);    // Set Volume to OFF
                   }
               }
 
@@ -305,7 +327,9 @@ void FakeAY_WriteData(u8 Value)
               UpdateNoiseAY();
               break;
 
-          // Volume Registers for all channels...
+          // ----------------------------------
+          // Volume Registers are below...
+          // ----------------------------------
           case 0x08:
               if (Value & 0x20)                                   // If Envelope Mode... see if this is being enabled
               {
@@ -352,10 +376,24 @@ void FakeAY_WriteData(u8 Value)
               UpdateNoiseAY();
               break;
 
-          // Envelope Period
+          // -----------------------------
+          // Envelope Period Register
+          // -----------------------------
           case 0x0B:
           case 0x0C:
-              envelope_period = ((ay_reg[0x0C] << 8) | ay_reg[0x0B]) & 0x3FFF;
+              {
+              u16 new_period = ((ay_reg[0x0C] << 8) | ay_reg[0x0B]) & 0x3FFF;
+              if ((envelope_period > 0) && (new_period == 0))
+              {
+                  prevEnvelopeA_enabled = false;
+                  prevEnvelopeB_enabled = false;
+                  prevEnvelopeC_enabled = false;
+                  sn76496W(0x9F, &aycol);
+                  sn76496W(0xBF, &aycol);
+                  sn76496W(0xDF, &aycol);
+              }
+              envelope_period = new_period;
+              }
               break;
       }
 }

diff --git a/arm9/source/cpu/tms9918a/tms9918a.c b/arm9/source/cpu/tms9918a/tms9918a.c
@@ -484,7 +484,7 @@ void RefreshLine3(u8 uY) {
  * Emulator calls this function to write byte 'value' into a VDP register 'iReg'
  ********************************************************************************/
 static u8 VDP_RegisterMasks[] = { 0x03, 0xfb, 0x0f, 0xff, 0x07, 0x7f, 0x07, 0xff };    
-ITCM_CODE byte Write9918(u8 iReg, u8 value) 
+byte Write9918(u8 iReg, u8 value) 
 { 
   int newMode;
   int VRAMMask;