Turing is designed to be operated from laptops, desktops,tablets and phones. A design decision was that use of the app would be essentially the same on all these different devices to make moving from use of one (say a desktop Apple) in school to another (say an Android tablet) at home as easy as possible. As a result all operations with the exception of naming programs is done by using mouse clicks.
All registers that can be altered are altered using stepper controls, up or down. When a value reaches FF (255) and is stepped up it revolves to 00. If a value is stepped down from 00 it revolves to FF.
Running the CPU
Turing's remote control is used to turn the processor's operations on and off, as shown below:
In the top row:
- The first button Fetch starts the CPU on its fetch/execute cycle.
- The next button is Execute which only shows when an instruction has been fetched.
- The next button Run tells Turing to carry out a complete program until a stop instruction is reached.
- The next button is Stop, which only shows when a program is running.
The bottom row shows
- rewind which resets the program counter to 0 and
- Speed control sets program running to a variety of speeds.
All of Turing's program options are controlled from its menu bar, as shown below
From left to right:
- H - indicates whether the CPU shows values in hexadecimal (H) or in binary (B).
- Q - This icon selects the Turing Quest mode, where users are set increasingly different challenges.
- The remote icon turns off the remote while programs are running (usually to make it easier to concentrate on what is happening).
- The bell shows or removes audio and visual distractions.
- Recycle - clears the CPU back to its default state and wipes the memory.
- The filing cabinet allows programs to be loaded
- This is the save icon which saves the current program.
- The information icon shows all of the Turing Help pages.