/* one or more argument, access a single register (write if second argument is given */
        if (argc >= 1)
        {
-               uint32_t opcode = strtoul(args[0], NULL, 0);
+               uint32_t opcode;
+               COMMAND_PARSE_NUMBER(u32, args[0], opcode);
 
                if (argc == 1)
                {
                }
                else if (argc == 2)
                {
-                       uint32_t value = strtoul(args[1], NULL, 0);
+                       uint32_t value;
+                       COMMAND_PARSE_NUMBER(u32, args[1], value);
+
                        if ((retval = arm720t_write_cp15(target, opcode, value)) != ERROR_OK)
                        {
                                command_print(cmd_ctx, "couldn't access cp15 with opcode 0x%8.8" PRIx32 "", opcode);