sim: syscall: hoist argc/argn/argnlen to common code

Now that the callback framework supports argv & envp, we can move
the Blackfin implementation of these syscalls to the common code.

sim/bfin/interp.c

@@ -144,39 +144,6 @@ bfin_syscall (SIM_CPU *cpu)
       tbuf += sprintf (tbuf, "exit(%i)", args[0]);
       sim_engine_halt (sd, cpu, NULL, PCREG, sim_exited, sc.arg1);
 
-#ifdef CB_SYS_argc
-    case CB_SYS_argc:
-      tbuf += sprintf (tbuf, "argc()");
-      sc.result = countargv ((char **)argv);
-      break;
-    case CB_SYS_argnlen:
-      {
-      tbuf += sprintf (tbuf, "argnlen(%u)", args[0]);
-	if (sc.arg1 < countargv ((char **)argv))
-	  sc.result = strlen (argv[sc.arg1]);
-	else
-	  sc.result = -1;
-      }
-      break;
-    case CB_SYS_argn:
-      {
-	tbuf += sprintf (tbuf, "argn(%u)", args[0]);
-	if (sc.arg1 < countargv ((char **)argv))
-	  {
-	    const char *argn = argv[sc.arg1];
-	    int len = strlen (argn);
-	    int written = sc.write_mem (cb, &sc, sc.arg2, argn, len + 1);
-	    if (written == len + 1)
-	      sc.result = sc.arg2;
-	    else
-	      sc.result = -1;
-	  }
-	else
-	  sc.result = -1;
-      }
-      break;
-#endif
-
     case CB_SYS_gettimeofday:
       {
 	struct timeval _tv, *tv = &_tv;

sim/common/syscall.c

@@ -141,6 +141,46 @@ cb_syscall (host_callback *cb, CB_SYSCALL *sc)
 
   switch (cb_target_to_host_syscall (cb, sc->func))
     {
+    case CB_SYS_argc:
+      result = countargv (cb->argv);
+      break;
+
+    case CB_SYS_argnlen:
+      {
+	if (sc->arg1 >= 0 && sc->arg1 < countargv (cb->argv))
+	  result = strlen (cb->argv[sc->arg1]);
+	else
+	  {
+	    result = -1;
+	    errcode = EINVAL;
+	  }
+      }
+      break;
+
+    case CB_SYS_argn:
+      {
+	if (sc->arg1 >= 0 && sc->arg1 < countargv (cb->argv))
+	  {
+	    const char *argn = cb->argv[sc->arg1];
+	    int len = strlen (argn);
+	    int written = sc->write_mem (cb, sc, sc->arg2, argn, len + 1);
+
+	    if (written == len + 1)
+	      result = sc->arg2;
+	    else
+	      {
+		result = -1;
+		errcode = EINVAL;
+	      }
+	  }
+	else
+	  {
+	    result = -1;
+	    errcode = EINVAL;
+	  }
+      }
+      break;
+
     case CB_SYS_argvlen :
       {
 	/* Compute how much space is required to store the argv,envp