Version 0.9a - see readme for details

Makefile

@@ -9,7 +9,7 @@ include $(DEVKITARM)/ds_rules
 
 export TARGET		:=	GimliDS
 export TOPDIR		:=	$(CURDIR)
-export VERSION		:=  0.9
+export VERSION		:=  0.9a
 
 ICON 		:= -b $(CURDIR)/C64_icon.bmp "GimliDS $(VERSION);wavemotion-dave;https://github.com/wavemotion-dave/GimliDS" 
 

README.md

@@ -109,6 +109,13 @@ Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 ```
 ## Change Log
 
+Version 0.9a release 02-May-2025 by wavemotion-dave
+  * Fixed TrueDrive loading so it doesn't alter the CPU speed (for games like Pang which were playing quite 'uneven').
+  * Bumped up volume of the SID output by 50% (was too quiet)
+  * Improved 1541 Drive emulation - mostly in the GCR and IEC areas. Nothing noticeable but should be more accurate.
+  * Fixed write floppy icon color (instead of the usual green, will flash blue).
+  * Tweaks to C64 keyboard graphic to be more authentic.
+
 Version 0.9 release 30-Apr-2025 by wavemotion-dave
   * New and improved key mapping - including the new Slide-n-Glide joysticks handling.
   * SID filtering improved for better audio rendering (Space Taxi voice heard!).

arm9/Makefile

@@ -28,7 +28,7 @@ ARCH	:=	-marm -mthumb-interwork
 
 CFLAGS	:=	-g -O3 -flto -Wall -Wformat=0 -Wno-sequence-point -Wno-delete-non-virtual-dtor -Wno-pointer-arith -Wno-register -Wno-narrowing -march=armv5te -mtune=arm946e-s -fomit-frame-pointer -ffast-math $(ARCH) -falign-functions=4 -frename-registers -finline-functions $(ARCH)
 
-CFLAGS	+=	$(INCLUDE) -DARM9 -D__NDS__=1 -DPRECISE_CPU_CYCLES=1 -DPRECISE_CIA_CYCLES=0 -DGLOBAL_VARS=1
+CFLAGS	+=	$(INCLUDE) -DARM9 -D__NDS__=1 -DPRECISE_CPU_CYCLES=1 -DGLOBAL_VARS=1
 CXXFLAGS	:=	$(CFLAGS) -fno-rtti -fno-exceptions
 
 ASFLAGS	:=	-g $(ARCH) -march=armv5te -mtune=arm946e-s

arm9/source/C64.cpp

@@ -1170,16 +1170,17 @@ void C64::main_loop(void)
         }
 
         // The order of calls is important here
-        int cycles = TheVIC->EmulateLine();
+        int cpu_cycles_to_execute = TheVIC->EmulateLine();
         TheSID->EmulateLine(SID_CYCLES_PER_LINE);
-#if !PRECISE_CIA_CYCLES
+        TheCIA1->EmulateLine(CIA_CYCLES_PER_LINE);
-        TheCIA1->EmulateLine(63);
+        TheCIA2->EmulateLine(CIA_CYCLES_PER_LINE);
-        TheCIA2->EmulateLine(63);
-#endif
 
+        // -----------------------------------------------------------------
+        // TrueDrive is more complicated as we must interleave the two CPUs
+        // -----------------------------------------------------------------
         if (ThePrefs.TrueDrive)
         {
-            int cycles_1541 = 64;
+            int cycles_1541 = FLOPPY_CYCLES_PER_LINE + CycleDeltas[myConfig.flopCycles];
             TheCPU1541->CountVIATimers(cycles_1541);
 
             if (!TheCPU1541->Idle)
@@ -1190,17 +1191,17 @@ void C64::main_loop(void)
                 // is now handled inside CPU_emuline.h for the 1541 processor
                 // to avoid the overhead of lots of function calls...
                 // -----------------------------------------------------------
-                TheCPU1541->EmulateLine(cycles_1541, cycles);
+                TheCPU1541->EmulateLine(cycles_1541, cpu_cycles_to_execute);
             }
             else
             {
-                TheCPU->EmulateLine(cycles);
+                TheCPU->EmulateLine(cpu_cycles_to_execute);
             }
         }
         else
         {
             // 1541 processor disabled, only emulate 6510
-            TheCPU->EmulateLine(cycles);
+            TheCPU->EmulateLine(cpu_cycles_to_execute);
         }
 
         linecnt++;

arm9/source/C64.h

@@ -30,6 +30,11 @@ const int CHAR_ROM_SIZE   = 0x1000;
 const int DRIVE_RAM_SIZE  = 0x800;
 const int DRIVE_ROM_SIZE  = 0x4000;
 
+#define SID_CYCLES_PER_LINE     63
+#define CIA_CYCLES_PER_LINE     63
+#define BAD_CYCLES_PER_LINE     23
+#define FLOPPY_CYCLES_PER_LINE  64
+
 class Prefs;
 class C64Display;
 class MOS6510;

arm9/source/CIA.h

@@ -116,9 +116,10 @@ public:
     uint8 IECLines;     // State of IEC lines (bit 7 - DATA, bit 6 - CLK, bit 4 - ATN)
 
 private:
+    void write_pa(uint8_t byte);
+    
     MOS6569 *the_vic;
     MOS6502_1541 *the_cpu_1541;
-    void write_pa(uint8_t byte);
 };
 
 

arm9/source/CPUC64.h

@@ -46,11 +46,6 @@
 #define PRECISE_CPU_CYCLES 0
 #endif
 
-// Set this to 1 for instruction-aligned CIA emulation
-#ifndef PRECISE_CIA_CYCLES
-#define PRECISE_CIA_CYCLES 0
-#endif
-
 
 // Interrupt types
 enum {

arm9/source/CPU_emulline.h

@@ -128,34 +128,23 @@
 
 #define ENDOP(cyc) last_cycles = cyc; break;
 
-#ifndef IS_CPU_1541
+#ifndef IS_CPU_1541 // If main C64 CPU we handle borrowed cycles
     // Main opcode fetch/execute loop
-#if PRECISE_CPU_CYCLES
     if (cycles_left) cycles_left -= borrowed_cycles;
 
     while (true)
     {
-#if PRECISE_CIA_CYCLES && !defined(IS_CPU_1541)
+        if ((cycles_left -= last_cycles) < 0) 
-        if (last_cycles) {
+        {
-            TheCIA1->EmulateLine(last_cycles);
-            TheCIA2->EmulateLine(last_cycles);
-        }
-#endif
-        if ((cycles_left -= last_cycles) < 0) {
             borrowed_cycles = -cycles_left;
             break;
         }
-#else
+#else // CPU is 1541
-    while ((cycles_left -= last_cycles) >= 0) {
-#endif
-
-#else
     cpu_cycles += CycleDeltas[myConfig.cpuCycles];
     MOS6510 *localCPU = the_c64->TheCPU;
 
     while ((cycles_left -= last_cycles) >= 0)
     {
-        cycle_counter += last_cycles;	// Needed for GCR timing
         // If we are 1541CPU, we want to alternate running instructions with the main CPU ...
         while (cpu_cycles > cycles_left) cpu_cycles -= localCPU->EmulateLine(0);
 #endif
@@ -1381,8 +1370,12 @@
         // Extension opcode
         case 0xf2: ext_opcode(); break;
         }
+        
+#ifdef IS_CPU_1541
+        cycle_counter += last_cycles;	// Needed for GCR timing
+#endif        
     }
 #ifdef IS_CPU_1541
         // See if there are any straggler cycles left for the CPU
-    while (cpu_cycles > 0) cpu_cycles -= the_c64->TheCPU->EmulateLine(1);
+    while (cpu_cycles > 0) cpu_cycles -= the_c64->TheCPU->EmulateLine(0);
 #endif

arm9/source/Display.cpp

@@ -162,7 +162,7 @@ void C64Display::UpdateLEDs(int l0, int l1)
 #define RET '\n' // Enter
 #define BSP 0x08 // Backspace
 #define CTL 0x21 // Ctrl
-#define SPC 0x20// Space
+#define SPC 0x20 // Space
 #define ATT 0x22 // At@
 #define UPA 0x23 //uparrow symbol
 #define RUN 0x00 // RunStop
@@ -602,7 +602,7 @@ void C64Display::PollKeyboard(uint8 *key_matrix, uint8 *rev_matrix, uint8 *joyst
                         else if (tilex < 194) c = '0';
                         else if (tilex < 213) c = '+';
                         else if (tilex < 233) c = '-';
-                        else if (tilex < 256) c = UPA;
+                        else if (tilex < 256) c = PND;
                     }
                     else if (tiley < 104) // QWERTY Row
                     {

arm9/source/SID.h

@@ -40,9 +40,6 @@
 #include <nds.h>
 #include <stdlib.h>
 
-
-#define SID_CYCLES_PER_LINE 63
-
 extern uint8 regs[32];
 extern uint8 last_sid_byte;
 extern int16_t EGDivTable[16];    // Clock divisors for A/D/R settings

arm9/source/VIC.cpp

@@ -1464,7 +1464,7 @@ int MOS6569::EmulateLine(void)
     {
         if (raster >= FIRST_DMA_LINE && raster <= LAST_DMA_LINE && ((raster & 7) == y_scroll) && bad_lines_enabled) {
             is_bad_line = true;
-            cycles_left = 23 + CycleDeltas[myConfig.badCycles];
+            cycles_left = BAD_CYCLES_PER_LINE;
         }
         goto VIC_nop;
     }
@@ -1485,7 +1485,7 @@ int MOS6569::EmulateLine(void)
         {
             // Turn on display
             display_state = is_bad_line = true;
-            cycles_left = 23 + CycleDeltas[myConfig.badCycles];
+            cycles_left = BAD_CYCLES_PER_LINE;
             rc = 0;
 
             // Read and latch 40 bytes from video matrix and color RAM

arm9/source/mainmenu.cpp

@@ -370,7 +370,7 @@ void SetDefaultGameConfig(void)
     myConfig.reserved7   = 0;
     myConfig.reserved8   = 0xA5;             // So it's easy to spot on an "upgrade" and we can re-default it
     myConfig.cpuCycles   = 0;                // Normal 63 - this is the delta adjustment to that
-    myConfig.badCycles   = 0;                // Normal 23 - this is the delta adjustment to that
+    myConfig.flopCycles  = 0;                // Normal 64 - this is the delta adjustment to that
     
     myConfig.offsetX     = 32;              // Push the side border off the main display
     myConfig.offsetY     = 19;              // Push the top border off the main display
@@ -378,7 +378,7 @@ void SetDefaultGameConfig(void)
     myConfig.scaleY      = 200;             // Scale the 200 pixels of C64 display to the DS 200 (yes, there is only 192 so this will cut... use PAN UP/DN)
 }
 
-s16 CycleDeltas[] = {0,1,2,3,4,5,6,7,8,9,-9,-8,-7,-6,-5,-4,-3,-2,-1};  // Used with myConfig.cpuCycles and myConfig.badCycles
+s16 CycleDeltas[] = {0,1,2,3,4,5,6,7,8,9,-9,-8,-7,-6,-5,-4,-3,-2,-1};  // Used with myConfig.cpuCycles and myConfig.flopCycles
 
 // ----------------------------------------------------------------------
 // Read file twice and ensure we get the same CRC... if not, do it again
@@ -575,7 +575,7 @@ const struct options_t Option_Table[1][20] =
         {"LCD JITTER",     {"NONE", "LIGHT", "HEAVY"},                                                  &myConfig.jitter,      3},
         {"DISK SOUND",     {"SFX OFF", "SFX ON"},                                                       &myConfig.diskSFX,     2},
         {"CPU CYCLES",     {CYCLE_DELTA_STR},                                                           &myConfig.cpuCycles,   19},
-        {"BAD CYCLES",     {CYCLE_DELTA_STR},                                                           &myConfig.badCycles,   19},        
+        {"1541 CYCLES",    {CYCLE_DELTA_STR},                                                           &myConfig.flopCycles,  19},
 
         {"D-PAD UP",       {KEY_MAP_OPTIONS},                                                           &myConfig.key_map[0],  64},
         {"D-PAD DOWN",     {KEY_MAP_OPTIONS},                                                           &myConfig.key_map[1],  64},

arm9/source/mainmenu.h

@@ -21,7 +21,7 @@ struct __attribute__((__packed__)) Config_t
     u8  reserved7;
     u8  reserved8;
     u8  cpuCycles;
-    u8  badCycles;
+    u8  flopCycles;
     s8  offsetX;
     s8  offsetY;
     s16 scaleX;