Refactored CPU_run

Uses pkg-config to source locations of libSDL.
As commented in Makefile, *may* cause issues with builds on Mac, but
there are known Mac-isms to make this work.
Also needs the math library for round() as referenced by video.o
This causes builds to start working on Ubuntu 24.04 with the default
SDL2 libraries installed using apt.
Arch is known to need pkg-config to use SDL libs too, but I'm not
sitting at my arch machine at the moment, so no idea if this is complete
for that platform.
A meta-build system *may* be a good idea?

Makefile

@@ -1,18 +1,24 @@
 # Variables
 CC = gcc
-CFLAGS = -Wall -Wextra -std=c11 -I/usr/local/include/SDL2
+# Probably this won't work on a mac using xcode.
-LDFLAGS = -L/usr/local/lib -lSDL2
+# See https://stackoverflow.com/questions/3071321/how-to-use-pkg-config-for-setting-include-paths-in-xcode
+# for possible workarounds?
+# != is a GNU make extension, so may also not work on *BSD
+SDL_CFLAGS!=pkg-config --cflags sdl2
+SDL_LFLAGS!=pkg-config --libs sdl2
+CFLAGS = -Wall -Wextra -std=c11 $(SDL_CFLAGS)
+LDFLAGS = $(SDL_LFLAGS) -lm
 SRC_DIR = src
 SOURCES = $(wildcard $(SRC_DIR)/*.c)
 OBJECTS = $(SOURCES:$(SRC_DIR)/%.c=%.o)
 TARGET = bsx
 
 # Default target
-all: $(TARGET)
+all: $(TARGET) Makefile
 
 # Linking
 $(TARGET): $(OBJECTS)
-	$(CC) $(LDFLAGS) -o $@ $^
+	$(CC) -o $@ $^ $(LDFLAGS)
 
 # Compiling
 %.o: $(SRC_DIR)/%.c

src/dispatch.c

@@ -8,6 +8,9 @@
  * Copyright (C) 2006 by Samuel A. Falvo II
  *
  * Modified for greater portability and virtual hardware independence.
+ * 
+ * Copyright (C) 2024 by Rebecca Buckingham
+ * highly modified to integrate with bsx emulator.
  */
 
 #define CPU_DISPATCH
@@ -15,10 +18,7 @@
 #include "cpu.h"
 #include "cpumicro.h"
 #include "util.h"
-
+#include <stdint.h>
-//#define LIMIT_INSTRUCTION_COUNT 10000
-
-//void CPUEvent_elapse( word32 cycles );
 
 int dispatch_quit = 0;
 
@@ -45,216 +45,164 @@ union {
 duala       atmp,opaddr;
 dualw       wtmp,otmp,operand;
 int         a1,a2,a3,a4,o1,o2,o3,o4;
-
-#ifdef OLDCYCLES
-byte        *cpu_curr_cycle_table;
-#endif
 void        (**cpu_curr_opcode_table)();
 
 extern int  cpu_reset,cpu_abort,cpu_nmi,cpu_irq,cpu_stop,cpu_wait,cpu_trace;
-extern int  cpu_update_period;
-
 extern int  cpu_irne64,cpu_irqt5;
 
+extern int  cpu_update_period;
+
 extern void (*cpu_opcode_table[1310])();
 
-#ifdef OLDCYCLES
+uint64_t last_update, next_update;
-/* Base cycle counts for all possible 1310 opcodes (262 opcodes x 5 modes).     */
-/* The opcode handlers may add additional cycles to handle special cases such   */
-/* a non-page-aligned direct page register or taking a branch.          */
 
-byte    cpu_cycle_table[1310] =
+#define RESET_OP    256
-{
+#define ABORT_OP    257
-    8, 6, 8, 4, 5, 3, 5, 6, 3, 2, 2, 4, 6, 4, 6, 5, /* e=0, m=1, x=1 */
+#define NMI_OP      258
-    2, 5, 5, 7, 5, 4, 6, 6, 2, 4, 2, 2, 6, 4, 7, 5,
+#define IRQ_OP      259
-    6, 6, 8, 4, 3, 3, 5, 6, 4, 2, 2, 5, 4, 4, 6, 5,
+#define IRNE64_OP   260
-    2, 5, 5, 7, 4, 4, 6, 6, 2, 4, 2, 2, 4, 4, 7, 5,
+#define IRQT5_OP    261
-    7, 6, 2, 4, 7, 3, 5, 6, 3, 2, 2, 3, 3, 4, 6, 5,
-    2, 5, 5, 7, 7, 4, 6, 6, 2, 4, 3, 2, 4, 4, 7, 5,
-    6, 6, 6, 4, 3, 3, 5, 6, 4, 2, 2, 6, 5, 4, 6, 5,
-    2, 5, 5, 7, 4, 4, 6, 6, 2, 4, 4, 2, 6, 4, 7, 5,
-    2, 6, 3, 4, 3, 3, 3, 6, 2, 2, 2, 3, 4, 4, 4, 5,
-    2, 6, 5, 7, 4, 4, 4, 6, 2, 5, 2, 2, 4, 5, 5, 5,
-    2, 6, 2, 4, 3, 3, 3, 6, 2, 2, 2, 4, 4, 4, 4, 5,
-    2, 5, 5, 7, 4, 4, 4, 6, 2, 4, 2, 2, 4, 4, 4, 5,
-    2, 6, 3, 4, 3, 3, 5, 6, 2, 2, 2, 3, 4, 4, 4, 5,
-    2, 5, 5, 7, 6, 4, 6, 6, 2, 4, 3, 3, 6, 4, 7, 5,
-    2, 6, 3, 4, 3, 3, 5, 6, 2, 2, 2, 3, 4, 4, 6, 5,
-    2, 5, 5, 7, 5, 4, 6, 6, 2, 4, 4, 2, 6, 4, 7, 5,
-    0, 0, 0, 0, 0, 0,
 
-    8, 6, 8, 4, 5, 3, 5, 6, 3, 2, 2, 4, 6, 4, 6, 5, /* e=0, m=1, x=0 */
+void handleSignal(int type) {
-    2, 6, 5, 7, 5, 4, 6, 6, 2, 5, 2, 2, 6, 5, 7, 5,
+  (**cpu_curr_opcode_table[type])();
-    6, 6, 8, 4, 3, 3, 5, 6, 4, 2, 2, 5, 4, 4, 6, 5,
-    2, 6, 5, 7, 4, 4, 6, 6, 2, 5, 2, 2, 5, 5, 7, 5,
-    7, 6, 2, 4, 0, 3, 5, 6, 4, 2, 2, 3, 3, 4, 6, 5,
-    2, 6, 5, 7, 0, 4, 6, 6, 2, 5, 4, 2, 4, 5, 7, 5,
-    6, 6, 6, 4, 3, 3, 5, 6, 5, 2, 2, 6, 5, 4, 6, 5,
-    2, 6, 5, 7, 4, 4, 6, 6, 2, 5, 5, 2, 6, 5, 7, 5,
-    2, 6, 3, 4, 4, 3, 4, 6, 2, 2, 2, 3, 5, 4, 5, 5,
-    2, 6, 5, 7, 5, 4, 5, 6, 2, 5, 2, 2, 4, 5, 5, 5,
-    3, 6, 3, 4, 4, 3, 4, 6, 2, 2, 2, 4, 5, 4, 5, 5,
-    2, 6, 5, 7, 5, 4, 5, 6, 2, 5, 2, 2, 5, 5, 5, 5,
-    3, 6, 3, 4, 4, 3, 6, 6, 2, 2, 2, 3, 5, 4, 6, 5,
-    2, 6, 5, 7, 6, 4, 8, 6, 2, 5, 4, 3, 6, 5, 7, 5,
-    3, 6, 3, 4, 4, 3, 6, 6, 2, 2, 2, 3, 5, 4, 6, 5,
-    2, 6, 5, 7, 5, 4, 8, 6, 2, 5, 5, 2, 6, 5, 7, 5,
-    0, 0, 0, 0, 0, 0,
-
-    8, 7, 8, 5, 7, 4, 7, 7, 3, 3, 2, 4, 8, 5, 8, 6, /* e=0, m=0, x=1 */
-    2, 6, 6, 8, 7, 5, 8, 7, 2, 5, 2, 2, 8, 5, 9, 6,
-    6, 7, 8, 5, 4, 4, 7, 7, 4, 3, 2, 5, 5, 5, 8, 6,
-    2, 6, 6, 8, 5, 5, 8, 7, 2, 5, 2, 2, 5, 5, 9, 6,
-    7, 7, 2, 5, 0, 4, 7, 7, 4, 3, 2, 3, 3, 5, 8, 6,
-    2, 6, 6, 8, 0, 5, 8, 7, 2, 5, 3, 2, 4, 5, 9, 6,
-    6, 7, 6, 5, 4, 4, 7, 7, 5, 3, 2, 6, 5, 5, 8, 6,
-    2, 6, 6, 8, 5, 5, 8, 7, 2, 5, 4, 2, 6, 5, 9, 6,
-    2, 7, 3, 5, 3, 4, 3, 7, 2, 3, 2, 3, 4, 5, 4, 6,
-    2, 6, 6, 8, 4, 5, 4, 7, 2, 5, 2, 2, 5, 5, 5, 6,
-    2, 7, 2, 5, 3, 4, 3, 7, 2, 3, 2, 4, 4, 5, 4, 6,
-    2, 6, 6, 8, 4, 5, 4, 7, 2, 5, 2, 2, 4, 5, 4, 6,
-    2, 7, 3, 5, 3, 4, 7, 7, 2, 3, 2, 3, 4, 5, 8, 6,
-    2, 6, 6, 8, 6, 5, 8, 7, 2, 5, 3, 3, 6, 5, 9, 6,
-    2, 7, 3, 5, 3, 4, 7, 7, 2, 3, 2, 3, 4, 5, 8, 6,
-    2, 6, 6, 8, 5, 5, 8, 7, 2, 5, 4, 2, 6, 5, 9, 6,
-    0, 0, 0, 0, 0, 0,
-
-    8, 7, 8, 5, 7, 4, 7, 7, 3, 3, 2, 4, 8, 5, 8, 6, /* e=0, m=0, x=0 */
-    2, 7, 6, 8, 7, 5, 8, 7, 2, 6, 2, 2, 8, 6, 9, 6,
-    6, 7, 8, 5, 4, 4, 7, 7, 4, 3, 2, 5, 5, 5, 8, 6,
-    2, 7, 6, 8, 5, 5, 8, 7, 2, 6, 2, 2, 6, 6, 9, 6,
-    7, 7, 2, 5, 0, 4, 7, 7, 3, 3, 2, 3, 3, 5, 8, 6,
-    2, 7, 6, 8, 0, 5, 8, 7, 2, 6, 4, 2, 4, 6, 9, 6,
-    6, 7, 6, 5, 4, 4, 7, 7, 4, 3, 2, 6, 5, 5, 8, 6,
-    2, 7, 6, 8, 5, 5, 8, 7, 2, 6, 5, 2, 6, 6, 9, 6,
-    2, 7, 3, 5, 4, 4, 4, 7, 2, 3, 2, 3, 5, 5, 5, 6,
-    2, 7, 6, 8, 5, 5, 5, 7, 2, 6, 2, 2, 5, 6, 6, 6,
-    3, 7, 3, 5, 4, 4, 4, 7, 2, 3, 2, 4, 5, 5, 5, 6,
-    2, 7, 6, 8, 5, 5, 5, 7, 2, 6, 2, 2, 5, 6, 5, 6,
-    3, 7, 3, 5, 4, 4, 7, 7, 2, 3, 2, 3, 5, 5, 8, 6,
-    2, 7, 6, 8, 6, 5, 8, 7, 2, 6, 4, 3, 6, 6, 9, 6,
-    3, 7, 3, 5, 4, 4, 7, 7, 2, 3, 2, 3, 5, 5, 8, 6,
-    2, 7, 6, 8, 5, 5, 8, 7, 2, 6, 5, 2, 6, 6, 9, 6,
-    0, 0, 0, 0, 0, 0,
-
-    8, 6, 8, 4, 5, 3, 5, 6, 3, 2, 2, 4, 6, 4, 6, 5, /* e=1, m=1, x=1 */
-    2, 5, 5, 7, 5, 4, 6, 6, 2, 4, 2, 2, 6, 4, 7, 5,
-    6, 6, 8, 4, 3, 3, 5, 6, 4, 2, 2, 5, 4, 4, 6, 5,
-    2, 5, 5, 7, 4, 4, 6, 6, 2, 4, 2, 2, 4, 4, 7, 5,
-    7, 6, 2, 4, 0, 3, 5, 6, 3, 2, 2, 3, 3, 4, 6, 5,
-    2, 5, 5, 7, 0, 4, 6, 6, 2, 4, 3, 2, 4, 4, 7, 5,
-    6, 6, 6, 4, 3, 3, 5, 6, 4, 2, 2, 6, 5, 4, 6, 5,
-    2, 5, 5, 7, 4, 4, 6, 6, 2, 4, 4, 2, 6, 4, 7, 5,
-    2, 6, 3, 4, 3, 3, 3, 6, 2, 2, 2, 3, 4, 4, 4, 5,
-    2, 5, 5, 7, 4, 4, 4, 6, 2, 4, 2, 2, 4, 4, 4, 5,
-    2, 6, 2, 4, 3, 3, 3, 6, 2, 2, 2, 4, 4, 4, 4, 5,
-    2, 5, 5, 7, 4, 4, 4, 6, 2, 4, 2, 2, 4, 4, 4, 5,
-    2, 6, 3, 4, 3, 3, 5, 6, 2, 2, 2, 3, 4, 4, 6, 5,
-    2, 5, 5, 7, 6, 4, 6, 6, 2, 4, 3, 3, 6, 4, 7, 5,
-    2, 6, 3, 4, 3, 3, 5, 6, 2, 2, 2, 3, 4, 4, 6, 5,
-    2, 5, 5, 7, 5, 4, 6, 6, 2, 4, 4, 2, 6, 4, 7, 5,
-    0, 0, 0, 0, 0, 0
-};
-#endif
-
-void CPU_run(void)
-{
-    word32  last_update,next_update;
-    int opcode;
-
-#ifdef LIMIT_INSTRUCTION_COUNT
-    long instructionCount = 0;
-#endif    
-
-    cpu_cycle_count = 0;
-    last_update = 0;
-    next_update = cpu_update_period;
-    E = 1;
-    F_setM(1);
-    F_setX(1);
-    CPU_modeSwitch();
-
-dispatch:
-//    CPUEvent_elapse( cpu_cycle_count );
-//    cpu_cycle_count = 0;
-    if (dispatch_quit)
-      return;
-  
-    // TODO remove this.
-#ifdef LIMIT_INSTRUCTION_COUNT    
-    instructionCount++;
-    if (instructionCount > LIMIT_INSTRUCTION_COUNT)
-      return;
-#endif      
-// #ifdef  E_UPDATE
-     if (cpu_cycle_count >= next_update) goto update;
- update_resume:
-// #endif
-
-#ifdef DEBUG
-    if (cpu_trace) goto debug;
-debug_resume:
-#endif
-    if (cpu_reset) goto reset;
-    if (cpu_stop) goto dispatch;
-    if (cpu_abort) goto abort;
-    if (cpu_nmi) goto nmi;
-    if (cpu_irq) goto irq;
-    if (cpu_irne64) goto irne64;
-    if (cpu_irqt5) goto irqt5;
-irq_return:
-    if (cpu_wait) { cpu_cycle_count++; goto dispatch; }
-    opcode = M_READ_OPCODE(PC.A);
-    PC.W.PC++;
-
-#ifdef OLDCYCLES
-    cpu_cycle_count += cpu_curr_cycle_table[opcode];
-#endif
-    (**cpu_curr_opcode_table[opcode])();
-
-    goto dispatch;
-
-/* Special cases. Since these don't happen a lot more often than they   */
-/* do happen, accessing them this way means most of the time the    */
-/* generated code is _not_ branching. Only during the special cases do  */
-/* we take the branch penalty (if there is one).            */
-
-// #ifdef E_UPDATE
-update:
-     E_UPDATE(cpu_cycle_count);
-     last_update = cpu_cycle_count;
-     next_update = last_update + cpu_update_period;
-     goto update_resume;
-// #endif
-
-#ifdef DEBUG
-debug:
-    CPU_debug();
-    goto debug_resume;
-#endif
-reset:
-    (**cpu_curr_opcode_table[256])();
-    goto dispatch;
-abort:
-    (**cpu_curr_opcode_table[257])();
-    goto dispatch;
-nmi:
-    (**cpu_curr_opcode_table[258])();
-    goto dispatch;
-irq:
-    if (P & 0x04) goto irq_return;
-    (**cpu_curr_opcode_table[259])();
-    goto dispatch;
-irne64:
-    if (P & 0x04) goto irq_return;
-     (**cpu_curr_opcode_table[260])();
-    goto dispatch;   
-irqt5:
-    if (P & 0x04) goto irq_return;
-     (**cpu_curr_opcode_table[261])();
-    goto dispatch;
 }
 
+void doUpdate() {
+  E_UPDATE(cpu_cycle_count);
+  last_update = cpu_cycle_count;
+  next_update = last_update + cpu_update_period;
+}
+
+void CPU_init(void) {
+  last_update = 0;
+  next_update = cpu_update_period;
+  cpu_cycle_count = 0;
+  E = 1;
+  F_setM(1);
+  F_setX(1);
+  CPU_modeSwitch();
+}
+
+void CPU_step(void) {
+  if (cpu_cycle_count >= next_update) doUpdate();
+  int opcode = M_READ_OPCODE(PC.A);
+  PC.W.PC++;
+  (**cpu_curr_opcode_table[opcode])();
+}
+
+void CPU_run(void) {
+  while (!dispatch_quit) {
+    if (cpu_trace) CPU_debug();
+    if (cpu_reset) { handleSignal(RESET_OP); continue; }
+    if (cpu_abort) { handleSignal(ABORT_OP); continue; }
+    if (cpu_nmi) { handleSignal(NMI_OP); continue; }
+    if (cpu_irq) { handleSignal(IRQ_OP); continue; }
+    if (cpu_irne64) { handleSignal(IRNE64_OP); continue; }
+    if (cpu_irqt5) { handleSignal(IRQT5_OP); continue; }
+    if (cpu_wait) { cpu_cycle_count++; continue; }
+    if (cpu_stop) continue;
+    CPU_step();
+  }
+}
+
+// void old_CPU_run(void)
+// {
+//     word32  last_update,next_update;
+//     int opcode;
+
+// #ifdef LIMIT_INSTRUCTION_COUNT
+//     long instructionCount = 0;
+// #endif    
+
+//     cpu_cycle_count = 0;
+//     last_update = 0;
+//     next_update = cpu_update_period;
+//     E = 1;
+//     F_setM(1);
+//     F_setX(1);
+//     CPU_modeSwitch();
+
+// dispatch:
+// //    CPUEvent_elapse( cpu_cycle_count );
+// //    cpu_cycle_count = 0;
+//     if (dispatch_quit)
+//       return;
+  
+//     // TODO remove this.
+// #ifdef LIMIT_INSTRUCTION_COUNT    
+//     instructionCount++;
+//     if (instructionCount > LIMIT_INSTRUCTION_COUNT)
+//       return;
+// #endif      
+// // #ifdef  E_UPDATE
+//      if (cpu_cycle_count >= next_update) goto update;
+//  update_resume:
+// // #endif
+
+// #ifdef DEBUG
+//     if (cpu_trace) goto debug;
+// debug_resume:
+// #endif
+//     if (cpu_reset) goto reset;
+//     if (cpu_stop) goto dispatch;
+//     if (cpu_abort) goto abort;
+//     if (cpu_nmi) goto nmi;
+//     if (cpu_irq) goto irq;
+//     if (cpu_irne64) goto irne64;
+//     if (cpu_irqt5) goto irqt5;
+// irq_return:
+//     if (cpu_wait) { cpu_cycle_count++; goto dispatch; }
+//     opcode = M_READ_OPCODE(PC.A);
+//     PC.W.PC++;
+
+// #ifdef OLDCYCLES
+//     cpu_cycle_count += cpu_curr_cycle_table[opcode];
+// #endif
+//     (**cpu_curr_opcode_table[opcode])();
+
+//     goto dispatch;
+
+// /* Special cases. Since these don't happen a lot more often than they   */
+// /* do happen, accessing them this way means most of the time the    */
+// /* generated code is _not_ branching. Only during the special cases do  */
+// /* we take the branch penalty (if there is one).            */
+
+// // #ifdef E_UPDATE
+// update:
+//      E_UPDATE(cpu_cycle_count);
+//      last_update = cpu_cycle_count;
+//      next_update = last_update + cpu_update_period;
+//      goto update_resume;
+// // #endif
+
+// #ifdef DEBUG
+// debug:
+//     CPU_debug();
+//     goto debug_resume;
+// #endif
+// reset:
+//     (**cpu_curr_opcode_table[256])();
+//     goto dispatch;
+// abort:
+//     (**cpu_curr_opcode_table[257])();
+//     goto dispatch;
+// nmi:
+//     (**cpu_curr_opcode_table[258])();
+//     goto dispatch;
+// irq:
+//     if (P & 0x04) goto irq_return;
+//     (**cpu_curr_opcode_table[259])();
+//     goto dispatch;
+// irne64:
+//     if (P & 0x04) goto irq_return;
+//      (**cpu_curr_opcode_table[260])();
+//     goto dispatch;   
+// irqt5:
+//     if (P & 0x04) goto irq_return;
+//      (**cpu_curr_opcode_table[261])();
+//     goto dispatch;
+// }
+
 /* Recalculate opcode_offset based on the new processor mode */
 
 void CPU_modeSwitch(void) {

src/main.c

@@ -26,7 +26,6 @@ void EMUL_hardwareUpdate(word32 timestamp) {
   }
     
   if (SDL_PollEvent(&sdl_event)) {
-    puts("got an event!");
     handleEvent(&sdl_event);
   }