M xywrun.c → xywrun.c

@@ -293,12 +293,39 @@ // ...
 };
 // clang-format on
 
+//// Internal VM state
+xyw_byte error_handler_entry_s = 0;
+
+int process_handlers()
+{
+    // Error handling
+    if (xyw_memory[SYSTEM_ERROR] != XYW_ERROR_NONE && !(xyw_memory[SYSTEM_STATE] & SYSTEM_STATE_ERROR))
+    {
+        xyw_word on_error_handler = XYW_PEEKW(&xyw_memory[SYSTEM_ON_ERROR]);
+        // If an error handler is set, jump to it
+        if (on_error_handler != 0)
+        {
+            xyw_dbg("Error occurred: %02X, jumping to error handler at %04X\n", xyw_memory[SYSTEM_ERROR], on_error_handler);
+            // Enter error state
+            xyw_memory[SYSTEM_STATE] |= SYSTEM_STATE_ERROR;
+            error_handler_entry_s = *s; // Record stack depth before pushing return address
+            ss_pushw(*pc);
+            *pc = on_error_handler;
+        }
+        else
+        {
+            // No error handler, halt execution
+            return xyw_memory[SYSTEM_ERROR];
+        }
+    }
+
+    return 0;
+}
+
 //// Main evaluation function - runs from current pc until BRK
-//// Returns 1 on success, 0 on error
 int xyw_eval(xyw_word start_pc)
 {
     *pc = start_pc;
-    xyw_byte error_handler_entry_s = 0;
 
     if (xyw_memory[SYSTEM_STATE] & xyw_debug)
     {
@@ -306,29 +333,12 @@ xyw_memory[SYSTEM_STATE] |= SYSTEM_STATE_DEBUG;
     }
     while ((xyw_memory[SYSTEM_STATE] & SYSTEM_STATE_RUNNING) && *pc < SYSTEM_MEMORY_START)
     {
-        if (xyw_memory[SYSTEM_ERROR] != XYW_ERROR_NONE && !(xyw_memory[SYSTEM_STATE] & SYSTEM_STATE_ERROR))
-        {
-            xyw_word on_error_handler = XYW_PEEKW(&xyw_memory[SYSTEM_ON_ERROR]);
-            // If an error handler is set, jump to it
-            if (on_error_handler != 0)
-            {
-                // Enter error state
-                xyw_memory[SYSTEM_STATE] |= SYSTEM_STATE_ERROR;
-                error_handler_entry_s = *s; // Record stack depth before pushing return address
-                ss_pushw(*pc);
-                *pc = on_error_handler;
-            }
-            else
-            {
-                // No error handler, halt execution
-                return xyw_memory[SYSTEM_ERROR];
-            }
-        }
+        process_handlers();
         xyw_dbg("PC: %04X -> %02X (%s) [U:%02X|S:%02X|X:%02X|Y:%02X|XW:%04X|YW:%04X]\n", *pc, xyw_memory[*pc], xyw_instructions[xyw_memory[*pc] & 0x1F], *u, *s, *x, *y, *xw, *yw);
         switch (xyw_memory[*pc])
         {
             // clang-format off
-            /* BRK */ case 0x00: return 1; // Simply return from evaluation
+            /* BRK */ case 0x00: return 0; // Simply return from evaluation
             /* PSH */ OPC_SR1(0x01, , if (rx||ry) { PUSH(ARG); } else { (*pc)++; PUSH(READ(*pc)); if (w) { (*pc)++; } })
             /* PSH */ OPC_SR1r(0x01, PUSH(a); PUSH(b); )
             /* POP */ OPC_SR1(0x02, , if (rx||ry) { SET(POP()); } else { POP(); } );
@@ -419,14 +429,13 @@ // Set direct page to device page by default
     xyw_memory[SYSTEM_PAGE] = 0xff;
 
     int eval_result = xyw_eval(0x0000);
-    if (eval_result)
+    if (!eval_result)
     {
-        xyw_word terminal_vector = XYW_PEEKW(&xyw_memory[TERMINAL_ON_KEYPRESS]);
-
-        // If terminal vector is set, enter stdin reading loop
-        if (terminal_vector)
+        // If terminal handler is set, enter stdin reading loop
+        xyw_word terminal_handler = XYW_PEEKW(&xyw_memory[TERMINAL_ON_KEYPRESS]);
+        if (terminal_handler)
         {
-            xyw_dbg("terminal.on_keypress vector set to %04X, entering input loop\n", terminal_vector);
+            xyw_dbg("terminal.on_keypress handler set to %04X, entering input loop\n", terminal_handler);
             while (xyw_memory[SYSTEM_STATE] & SYSTEM_STATE_RUNNING)
             {
                 int c = getch();