sim65 use error codes outside the simulated program's range for non-sim errors

src/sim65/error.h

@@ -49,10 +49,12 @@
 
 
 
-#define SIM65_ERROR         0x7F
-/* Does not use EXIT_FAILURE because it may overlap with test results. */
+#define SIM65_ERROR         -1
+/* An error result for errors that are not part of the simulated test.
+** Note that set simulated test can only return 8-bit errors 0-255.
+*/
 
-#define SIM65_ERROR_TIMEOUT 0x7E
+#define SIM65_ERROR_TIMEOUT -2
 /* An error result for max CPU instructions exceeded. */
 
 extern int PrintCycles;

src/sim65/paravirt.c

@@ -124,7 +124,7 @@ static unsigned PopParam (unsigned char Incr)
 static void PVExit (CPURegs* Regs)
 {
     Print (stderr, 1, "PVExit ($%02X)\n", Regs->AC);
-    SimExit (Regs->AC);
+    SimExit (Regs->AC); /* Error code in range 0-255. */
 }