fun-with-FPGA

This project consists of a Rust compiler which will compile the fun language into a custom ISA, which will be run on the Altera Cyclone V FPGA.

Fun Language

Language Overview

• Source character encoding: A program is represented as a string of ASCII characters in a .fun whose name is passed as a command line argument to the compiler.

• Lexical rules: the language has the following tokens:

  • keywords: "if" "else" "while" "fun" "_IN_" and "print"
  • operators and special characters: = == ( ) { } + *
  • identifiers: start with lower case letters followed by a sequence of lower case letters and numbers.
  • immediate values: sequences of digits representing integers. They always start with a digit but could contain _ characters that are ignored

• Syntax: The syntax is C-Like, but ( ) are not allowed in right-hand expressions to specify order of operations.

Languages Sematics

• All variables are 16 bit unsigned integers
• + performs unsigned integer addition (mod 2^16)
• * performs unsigned integer multiplications (mod 2^16)
• x == y returns 1 if x and y contain the same bit pattern and 0 otherwise
• x = <exp> assigns the result of evaluating <exp> to x
• The if statement has one of the forms:
  • if <exp> <statement>
  • if <exp> <statement> else <statement>
• The while statement has the form: while <exp> <statement>
• { } is used to block statements, making a sequence of statements appear like a single one
• The print statement has the form: print <exp> and prints the numerical value of the expression followed by a new line
• The fun expression is of this form: fun <statement> and returns an opaque 64-bit quantity that can be used to specify a function
• A function can be called by: <identifier> () where the identifier contains a value returned by "fun"
• _IN_ prompts the user for input and pauses the program until input is given.