Add non multithread mode

assembler/assembler.c

@@ -210,9 +210,9 @@ int resolveMOV(const char *dest, const char *src) {
     }
 }
 
-int resolveALU(int baseOpcode, const char *src) {
+int resolveALU(int baseOpcode, const char *src, const char *dest) {
     // baseOpcode is one of our special negative values for ADD, SUB, etc.
-    if (src[0] == 'R' || src[0] == 'r') {
+    if (dest[0] == 'R' || dest[0] == 'r') {
         switch (baseOpcode) {
             case -3:
                 return ADD_RN_RM;
@@ -230,6 +230,11 @@ int resolveALU(int baseOpcode, const char *src) {
                 return OR_RN_RM;
             case -10:
                 return XOR_RN_RM;
+            default:
+                return -1;
+        }
+    } else if (src[0] == 'r' || src[0] == 'R' && baseOpcode < -11) {
+        switch (baseOpcode) {
             case -12:
                 return INC_RN;
             case -13:
@@ -467,7 +472,7 @@ uint32_t completePass(const char *source, CPU *cpu, bool erase) {
                 fprintf(stderr, "Error: %s requires one operand.\n", mnemonic);
                 return 1;
             }
-            int resolvedOpcode = resolveALU(baseOpcode, operand1);
+            int resolvedOpcode = resolveALU(baseOpcode, operand1, operand2);
             cpu->memory[addr++] = resolvedOpcode;
             if (operand1[0] == 'R' || operand1[0] == 'r') {
                 int reg = parseRegister(operand1);
@@ -491,7 +496,7 @@ uint32_t completePass(const char *source, CPU *cpu, bool erase) {
                 fprintf(stderr, "Error: %s requires two operands.\n", mnemonic);
                 return 1;
             }
-            int resolvedOpcode = resolveALU(baseOpcode, operand1);
+            int resolvedOpcode = resolveALU(baseOpcode, operand1, operand2);
             cpu->memory[addr++] = resolvedOpcode;
             int regDest = parseRegister(operand1);
             cpu->memory[addr++] = regDest;
@@ -509,7 +514,7 @@ uint32_t completePass(const char *source, CPU *cpu, bool erase) {
                 fprintf(stderr, "Error: JMP requires one operand.\n");
                 return 1;
             }
-            int resolvedOpcode = resolveALU(baseOpcode, operand1);
+            int resolvedOpcode = resolveALU(baseOpcode, operand1, operand2);
             cpu->memory[addr++] = resolvedOpcode;
             if (operand1[0] == '+' || operand1[0] == '-') {
                 // Relative jump: one-byte offset.
@@ -529,7 +534,7 @@ uint32_t completePass(const char *source, CPU *cpu, bool erase) {
                 fprintf(stderr, "Error: %s requires three operands.\n", mnemonic);
                 return 1;
             }
-            int resolvedOpcode = resolveALU(baseOpcode, operand1);
+            int resolvedOpcode = resolveALU(baseOpcode, operand1, operand2);
             cpu->memory[addr++] = resolvedOpcode;
             // Encode the source operand (register or memory).
             if (operand1[0] == 'R' || operand1[0] == 'r') {

assembler/assembler.h

@@ -70,7 +70,7 @@ int getOpcode(char *mnemonic);
 //
 int resolveMOV(const char *dest, const char *src);
 
-int resolveALU(int baseOpcode, const char *src);
+int resolveALU(int baseOpcode, const char *src, const char *dest);
 
 //
 // The first pass scans the assembly source file to record all labels and their addresses.

main.c

@@ -28,6 +28,8 @@ SDL_Renderer *renderer = NULL;
 #define smallFont fonts[1]
 #define smallerFont fonts[2]
 
+//#define CPU_THREADED
+
 #define fontCount 3
 
 BitmapFont fonts[fontCount];
@@ -49,8 +51,10 @@ TextEditor editors[editorCount];
 unsigned long frames = 0;
 bool cursor = true;
 
+#ifdef CPU_THREADED
 pthread_t cpu_thread;
 pthread_mutex_t cpu_mutex = PTHREAD_MUTEX_INITIALIZER;
+#endif
 
 void msleep(unsigned int milliseconds) {
     struct timespec ts;
@@ -59,32 +63,54 @@ void msleep(unsigned int milliseconds) {
     nanosleep(&ts, NULL);
 }
 
-void *cpu_loop(void *arg) {
-    uint64_t last_tick = SDL_GetTicks64();
-    while (running) {
-        pthread_mutex_lock(&cpu_mutex);
+static uint64_t last_tick = 0;
 
-        if (!(cpu.mode & (CPU_MODE_PAUSED | CPU_MODE_HALTED | CPU_MODE_ERROR))) {
-            step(&cpu);
-        } else {
-            pthread_mutex_unlock(&cpu_mutex);
-            msleep(10);
-        }
+// This function executes one iteration of the CPU loop (non-blocking)
+void cpu_step(void) {
+    if (last_tick == 0) {
+        last_tick = SDL_GetTicks64();
+    }
 
-        if (cpu.mode & CPU_MODE_SECOND) {
-            pthread_mutex_unlock(&cpu_mutex);
-            msleep(1000);
-            continue;
-        } else if (cpu.mode & CPU_MODE_FRAME) {
-            uint64_t frame_duration = SDL_GetTicks64() - last_tick;
-            if (frame_duration < delayNeeded) {
-                pthread_mutex_unlock(&cpu_mutex);
-                msleep(delayNeeded - frame_duration);
-                continue;
-            }
-            last_tick = SDL_GetTicks64();
-        }
+#ifdef CPU_THREADED
+    pthread_mutex_lock(&cpu_mutex);
+#endif
+
+    if (!(cpu.mode & (CPU_MODE_PAUSED | CPU_MODE_HALTED | CPU_MODE_ERROR))) {
+        step(&cpu);
+    } else {
+#ifdef CPU_THREADED
         pthread_mutex_unlock(&cpu_mutex);
+#endif
+        return;
+    }
+
+    if (cpu.mode & CPU_MODE_SECOND) {
+#ifdef CPU_THREADED
+        pthread_mutex_unlock(&cpu_mutex);
+#endif
+        msleep(1000);
+        return;
+    } else if (cpu.mode & CPU_MODE_FRAME) {
+        uint64_t frame_duration = SDL_GetTicks64() - last_tick;
+        if (frame_duration < delayNeeded) {
+#ifdef CPU_THREADED
+            pthread_mutex_unlock(&cpu_mutex);
+#endif
+            msleep(delayNeeded - frame_duration);
+            return;
+        }
+        last_tick = SDL_GetTicks64();
+    }
+
+#ifdef CPU_THREADED
+    pthread_mutex_unlock(&cpu_mutex);
+#endif
+}
+
+// Blocking loop for running as a thread
+void *cpu_loop(void *arg) {
+    while (running) {
+        cpu_step();
     }
     return NULL;
 }
@@ -415,8 +441,6 @@ SDL_Keycode ConvertKPToNonKP(SDL_Keycode keycode) {
     }
 }
 
-uint8_t cpuSpeedTemp = 0;
-
 int processEvent(SDL_Event e) {
     if (e.type == SDL_QUIT) { return 0; }
     else if (e.type == SDL_WINDOWEVENT && e.window.event == SDL_WINDOWEVENT_RESIZED) {
@@ -642,10 +666,18 @@ int main(__attribute__((unused)) int argc, __attribute__((unused)) char *args[])
     SDL_Event e;
     Uint64 start;
     Uint64 end;
+#ifdef CPU_THREADED
     pthread_create(&cpu_thread, NULL, cpu_loop, NULL);
+#endif
     while (running) {
         start = SDL_GetTicks64();
+#ifndef CPU_THREADED
+        cpu_step();
+#endif
+#ifdef CPU_THREADED
+
         pthread_mutex_lock(&cpu_mutex);
+#endif
         while (SDL_PollEvent(&e)) {
             running = processEvent(e);
         }
@@ -671,7 +703,9 @@ int main(__attribute__((unused)) int argc, __attribute__((unused)) char *args[])
                 updateState(false);
             }
         }
+#ifdef CPU_THREADED
         pthread_mutex_unlock(&cpu_mutex);
+#endif
         end = SDL_GetTicks64();
         const unsigned long timeNeeded = end - start;
         if (timeNeeded < delayNeeded) {
@@ -706,8 +740,9 @@ int main(__attribute__((unused)) int argc, __attribute__((unused)) char *args[])
     destroy_seven_segment(&displayF);
     destroy_seven_segment(&displayG);
     destroy_seven_segment(&displayH);
-
+#ifdef CPU_THREADED
     pthread_join(cpu_thread, NULL);
+#endif
     if (renderer) SDL_DestroyRenderer(renderer);
     if (window) SDL_DestroyWindow(window);
 

peripherals/switches.c

@@ -85,7 +85,7 @@ void init_switches(Switches *switches, SDL_Renderer *renderer, int x, int y, int
         fprintf(stderr, "Failed to create texture: %s\n", SDL_GetError());
         exit(EXIT_FAILURE);
     }
-    switches->value = (1 << 0) | (1 << 1);
+    switches->value = 0;
     generate_switch_rects(switches);
     update_switches_texture(renderer, switches);
 }