Firefly

##Firefly computing system

To use this software, you must have python3 and tkinter installed.

On Debian Linux derivatives:

sudo apt-get install python3 python3tk
python3 Jarvis.py

• Ultron.py is the high level language compiler (High level language -> VM intermediate format).
• VirtualMachine.py is the virtual machine translator (VM commands -> Assembly commands).
• Jarvis.py is the assembler and CPU simulator (Assembly commands -> binary).

The test code and some skeleton files are provided by the book The Elements of Computing Systems by Noam Nisan and Shimon Schocken (MIT Press).

Directory Structure

tecs

The tecs directory contains all of the source code included with the book.

OS

The OS directory contains the operating system files. The files ending in .jack are the high level language code, including:

• Array.jack

  • Create new arrays with var myArray = Array.new(size) and destroy them with myArray.destroy().

• Keyboard.jack

  • keyPressed() Returns an ASCII code of the current key being pressed.
  • readChar() Reads the next character from the keyboard, waits until a key is pressed and then released, echoes the key to the screen, and returns the value of the pressed key.
  • readLine(String message) Prints a message on the screen, reads the next line of input until a newline character, and returns its value.
  • readInt(String message) Prints a message on the screen, reads the next line of input until a newline character, and returns its value as an integer, until the first non numeric character.

• Math.jack

  • twoToThe(x) Returns 2^x.
  • abs(x) Returns the absolute value of ``x.
  • multiply(x, y) Returns the product of x and y.
  • bit(x, j) Returns true of the j-th bit of x is 1 and false otherwise.
  • divide(x, y) Returns the integer part of x/y. Returns 0 if y > x. Returns -1 for overflow.
  • xor(x, y) Returns x XOR y.
  • sqrt(x) Returns the square root of x.
  • max(x, y) Returns the greater number of x and y.
  • min(x, y) Returns the smaller number of x and y.
  • mod(n, base) Returns the remainder of the division of n / base

• Memory.jack

  • peek(address) Returns the value of memory at location address.
  • poke(address, value) Sets the value of memory location address to value.
  • alloc(size) Allocates a block of memory of size size and returns a reference to its base address.
  • deAlloc(object) De-allocates a given object and frees its space.

• Output.jack

  • moveCursor(i, j) Moves the cursor to the jth column of the ith row.
  • print(String s) Prints an anonymous String and then destroys it.
  • printLoc() Prints the location of the cursor to the screen
  • printChar(c) Prints c at the cursor location and advances the cursor one column forward.
  • printString(s) Prints s starting at the cursor location and advances the cursor appropriately.
  • printInt(i) Prints the Integer i at the cursor location and advances the cursor appropriately.
  • println() Advances the cursor to the beginning of the next line.
  • backSpace() Moves the cursor one column back.

• String.jack

  • new(maxLength) Constructs a new String of maximum length maxLength.
  • myString.dispose() Disposes this string and frees its space.
  • myString.length() Returns the length of this String.
  • myString.charAt(j) Returns the character at location j. If j < 0, counts from the end of the string backwards to j.
  • myString.setCharAt(j, c) Sets the jth character of this string to be c.
  • myString.appendChar(c) Appends the character c to the end of this String.
  • myString.slice(from, to) Returns a slice of this String.
  • myString.grow(n) Grows this string by n characters.
  • myString.eraseLastChar() Erases the last character in this String.
  • myString.intValue() Returns the integer value of this string until the first non-numeric character.
  • myString.setInt(n) Sets this string to hold a representation of the given number n.
  • newLine() Returns the newline character.
  • backSpace() Returns the backspace character.
  • doubleQuote() Returns the double quote character.

• Sys.jack

  • init() This method is called automatically upon bootstrapping, initializing all .init() methods of all other classes in the OS.
  • halt() Halts the execution of the processor, hopefully without catching anything on fire.
  • wait(duration) Waits approximately duration milliseconds and then returns.
  • error(code) Prints out the given error code and then halts.
  • breakpoint() An empty function to be used to inject breakpoints while debugging.

Also, this directory will contain Main.jack which houses the main() method, which is the beginning point of any application defined code.