Turing is a small virtual machine demonstrating the principles of computation, it is intended as a learning tool for those who wish to learn more about computer science.
Turing is written in Common Lisp using the SBCL interpreter, other interpreters were not tested, however no special extensions were used so it should be portable among implementations.
To use simply call the function run-machine in the turing namespace, an example is shown below.
Prorgrams are strings enclosed in double quotes with operations and operands separated by commas, spaces are not permitted in a program, only numbers and commas. There is a program counter that one can manipulate with the jump commands, under normal conditions the op-code under the program counter will be executed. The program counter will then be advanced by the number of parameters the op-code accepts + 1, so if an op-code has 3 parameters the program counter will advance by 4.
$ cd turing-machine
$ sbcl
This is SBCL 1.5.9, an implementation of ANSI Common Lisp.
More information about SBCL is available at
<http://www.sbcl.org/>.
SBCL is free software, provided as is, with absolutely no warranty.
It is mostly in the public domain; some portions are provided under BSD-style licenses. See the CREDITS and COPYING files in the distribution for more information.
* (load "src/main")
T
* (turing:run-machine "101,0,0,3,0")
* (101 0 0 202 0)
* (quit)
Inside the session, if you wish to run the test suite that comes with this project you can.
(asdf:run-system :turing)
Ensure that you have sbcl installed and available in your path and the following instructions and sample program should be enough. You will probably need to ensure you have quicklisp installed in order to install the rove test framework in which the tests are written.
$ git clone github.com/nmunro/turing-machine
These are the implemented op-codes in the virtual machine, these are classified by type.
- Numbers less than 100 are reserved for halting and no-op.
- Numbers beginning with 10 are arithmetic operations.
- Numbers beginning with 20 are program flow.
- Numbers beginning with 30 are comparison/equality operators.
| Number | Name | Arguements |
|---|---|---|
| 0 | Halt | - |
| 1 | Noop | - |
| 101 | Add | 3: position of first number, position of second number, position to write result to |
| 102 | Multiply | 3: position of first number, position of second number, position to write result to |
| 103 | Subtract | 3: position of first number, position of second number, position to write result to |
| 104 | Divide | 3: position of first number, position of second number, position to write result to |
| 105 | Increment | 1: position of number to increase by 1 |
| 106 | Decrement | 1: position of number to decrement by 1 |
| 201 | Jump | 1: position to jump to |
| 202 | Jump if | 3: boolean check, position if true, position if false |
| 301 | Equals | 3: position of first number, position of second number, position to write result to |
| 302 | Greater than | 3: position of first number, position of second number, position to write result to |
| 303 | Greater than equal | 3: position of first number, position of second number, position to write result to |
| 304 | Less than | 3: position of first number, position of second number, position to write result to |
| 305 | Less than equal | 3: position of first number, position of second number, position to write result to |
| 306 | And | 3: position of first number, position of second number, position to write result to |
| 307 | Or | 3: position of first number, position of second number, position to write result to |
| 308 | Not | 2: position of first number, position to write result to |