Em Language

This converts c-like code into MIPS (32 bit)

NOTE: The author makes clear that using this tool to complete work where it is not permitted, such as in COMP1521 lab activities and assignments, is not condoned, and takes no responsibility for such events.

Features

• If statementsz
• While/For loops
• Gotos/Labels
• Hexadecimal support
• Functions
• Function arguments
• Global/Local variables
• Arrays (no multidemensional support)
• Indexing
• Int/Char types
• Poke/Peek
• Bitwise operators
• Pre/Post increment/decrement
• Pointers
• String literals
• Input (String, Char, Int)/Print
• Normal mathy stuff and negation
  • - + % / *
• Bodmas
• Logical operators (besides || and &&)
• Structs
• Union
• Comments
• typedef
• enums
• break/continue
• switch
• macros
• Array initisaliation
• Local variable initialisation
• Type casting
• octal support
• Sizeof operator
• Ternary operator
• || and && operators
• Function headings (WIP)
• Register spilling (broken at the moment)
• Lazy Evaluation
• Compiler directives
  • Including the ability to manually name any label

What will be added soon (Hopefully)

• Multidimensional arrays
• Namespace
• Inline assembly and registers
• Scopes (probs wont be done)
• scope creation (probs wont be done)
• header comments
• statement commenting
  • prints the original statement in assembly file next to instruction as comment

Low chance of being added but I might try

• Heap support
• unsigned types
• Optimization
• Error recovery
• Graph Colouring for spilling registers

Documentation

Order of Procedence

The higher the number, the higher the procedence.

Operator	Precedence
( )	13
<	12
>	12
<=	12
>=	12
==	11
!=	11
%	10
/	10
*	10
+	9
-	9
<<	8
>>	8
&	7
^	6
|	5
&&	4
||	3
? :	2
=	1
+=	1
-=	1
*=	1
/=	1
%=	1
,	0

Preprocessor

BNF for include and define:

    <preprocessor> ::= "#" <directive>
    <directive> ::= "include" (<string> | "<" <text> ">" ) | "define" <id> <string>

Example:

    #include "stdio.h"
    #include <stdio.h>
    #define PI 3.14

NOTE Includes for the standard library is different to C. Also its currently not working as intended.

Variables

BNF for global variables:

    <statement> ::= <type> <declaration> ( "," <declaration> )* ";"
    <declaration> ::= <identifier> [ "[" <number> "]" ] [ "=" <value> | "=" "{" <value> ( "," <value> )* "}" ]

Example:

    i32 a = 2;
    i8 bob;
    i32 b, c = 3;
    i32 d[10] = { 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 }, e;
    i32 d[10] = { 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 }, e = 2;
    i32 d[10], e = 2;
    i32 d[10], e;
    i8 *a = "Hello";
    i8 *deez_nuts = "Gottem";

NOTE: You can only go up to 15 *'s.

BNF for local variables:

    <statement> ::= <type> <declaration> ( "," <declaration> )* ";"
    <declaration> ::= <identifier> [ "[" <expression> "]" ] | <identifier> [ "=" <expression> ]

Example:

   i32 a;
   i32 a = 2, b;
   i32 a[10], b;
   i8 *a;
   i8 **a;

NOTE: You cannot initialise local arrays.
NOTE: You can only go up to 15 *'s.

Structs

BNF for structs:

    <struct> ::= "struct" <id> "{" <statements> "}"

Example:

    struct Jeff {
        i32 money;
        i8 *name;
        i8 address[120];
        struct Jeff *next;
    }

NOTE: You cannot initialise values in the struct.

Enums

BNF for enums:

    <enum> ::= "enum" <id> "{" <id> [ "=" <number> ] ( "," <id> [ "=" <number> ] )* "}"

Example:

    enum Jeff {
        JEFF = 1,
        JEFFERY = 2,
        JEFFREY = 3
    }

Typedef

BNF for typedef:

    <typedef> ::= "typedef" <type> <id>

Example:

    typedef i32 Jeff;
    typedef i8 *Jeff;
    typedef struct Jeff poo;

Unions

BNF for unions:

    <union> ::= "union" <id> "{" <statements> "}"

Example:

    union Jeff {
        i32 money;
        i8 *name;
        i8 address[120];
        struct Jeff *next;
    }

Functions

BNF for functions:

       <func> ::= <type> <id> "(" [ <args> ] ")" "{" <stmts> "}"

Example:

    i32 Domain_Expansion(i32 a, i32 b) {
        print("Nah I'd win", 10);
        print("a: ", a, ", b: ", b, 10);
        return 0;
    }

You can also put void as the parameter.

i32 main(void) {
    printf("We also want to make it clear that using this tool to create solutions to lab activities and assignments strictly against the rules of the course and will be treated as academic misconduct.");
}

BNF for function calls:

    <call> ::= <id> "(" [ <args> ] ")"

Example:

    Domain_Expansion(69, 420);

Pointers

BNF for pointers:

    <ptr> ::= "*" <id>

Example:

    i32 a = 2;
    i32 *b = &a;
    i32 **c = &b;
    print(**c, 10);

NOTE: You can only go up to 15 *'s.

Gotos/Labels

BNF for labels:

    <label> ::= "label" <id> ":"

Example:

    label start:
    print("Hello", 10);

BNF for gotos:

    <goto> ::= "goto" <id> ";"

Example:

    label start;
    print("This is gold experience requiem", 10);
    goto start;

If statements

BNF for if statements:

    <if> ::= "if" "(" <expr> ")" "{" <stmts> "}"

Example:

    i32 a = 2;
    if (a == 2) {
        print("a is 2", 10);
    }

While loops

BNF for while loops:

    <while> ::= "while" "(" <expr> ")" "{" <stmts> "}"

Example:

    i32 a = 0;
    while (a < 10) {
        print(a, 10);
        a = a + 1;
    }

For loops

BNF for for loops:

    <for> ::= "for" "(" <set> <expr> ";" <set> ")" "{" <stmts> "}"

Example:

    i32 a = 0;
    for (a = 0; a < 10; a++) {
        print(a, 10);
    }

Break/Continue

BNF for break/continue:

    <breakcont> ::= "break" ";"
                 | "continue" ";"

Example:

    i32 a = 0;
    for (a = 0; a < 10; a++) {
        if (a == 5) {
            break;
        }
        print(a, 10);
    }

Switch

BNF for switch:

    <switch> ::= "switch" "(" <expr> ")" "{" <cases> "}"
    <cases> ::= <case> <cases>
              | <default>
    <case> ::= "case" <expr> ":" <stmts>
    <default> ::= "default" ":" <stmts>

Example:

    i32 a = 2;
    switch (a) {
        case 1:
            print("a is 1", 10);
            break;
        case 2:
            print("a is 2", 10);
            break;
        default:
            print("a is not 1 or 2", 10);
            break;
    }

Input/Print

BNF for input:

    <input> ::= "input" "(" <id> "," <type> ")"

Example:

    i32 a;
    input(a, i32);
    i8 choice;
    input(choice, i8);
    i8 creditCardDetails[120];
    input(creditCardDetails, i8*);

NOTE: Input implicitly uses the array size.

BNF for print:

    <print> ::= "print" "(" <args> ")"

Example:

    print("Hello", 10);

Bitwise operators

BNF for bitwise operators:

    <bitwise> ::= <expr> "&" <expr>
                | <expr> "|" <expr>
                | <expr> "^" <expr>
                | <expr> "<<" <expr>
                | <expr> ">>" <expr>

Example:

    i32 a = 2;
    i32 b = 3;
    print(a & b, 10);
    print(a | b, 10);
    print(a ^ b, 10);
    print(a << b, 10);
    print(a >> b, 10);

Logical operators

BNF for logical operators:

    <logical> ::= <expr> "==" <expr>
                | <expr> "!=" <expr>
                | <expr> "<" <expr>
                | <expr> ">" <expr>
                | <expr> "<=" <expr>
                | <expr> ">=" <expr>

Example:

    i32 a = 2;
    i32 b = 3;
    print(a == b, 10);
    print(a != b, 10);
    print(a < b, 10);
    print(a > b, 10);
    print(a <= b, 10);
    print(a >= b, 10);

BNF for ternary operator:

    <ternary> ::= <expr> "?" <expr> ":" <expr>

Example:

    i32 a = 2;
    i32 b = 3;
    print(a == b ? 1 : 0, 10);

BNF for and and or operators:

    <andor> ::= <expr> "&&" <expr>
              | <expr> "||" <expr>

Example:

    i32 a = 2;
    i32 b = 3;
    print(a == 2 && b == 3, 10);
    print(a == 2 || b == 3, 10);

BNF for not operator:

    <not> ::= "!" <expr>

Pre/Post increment/decrement

BNF for pre/post increment/decrement:

    <incdec> ::= "++" <id>
               | "--" <id>
               | <id> "++"
               | <id> "--"

Example:

    i32 a = 2;
    print(a++, 10);
    print(a, 10);
    print(++a, 10);
    print(a, 10);

    print(a--, 10);
    print(a, 10);
    print(--a, 10);
    print(a, 10);

NOTE: You can only have one increment/decrement per statement.

Poke/Peek

BNF for poke/peek:

    <pokepeek> ::= "poke" "(" <expr> "," <expr> ")"
                 | "peek" "(" <expr> ")"

Example:

    i32 a = 2;
    poke(0x10010000, a);
    print(peek(0x10010000), 10);

String literals

BNF for string literals:

    <string> ::= <string> <string>
               | <char>

Example:

    i8 *sigma = "Skibidi toilet\n";
    i8 *hello = "how, " "are, " "you?\n";

Artihmetic

BNF for arithmetic:

    <arith> ::= <expr> "+" <expr>
              | <expr> "-" <expr>
              | <expr> "*" <expr>
              | <expr> "/" <expr>
              | <expr> "%" <expr>

Example:

    i32 a = 2;
    i32 b = 3;
    print(a + b, 10);
    print(a - b, 10);
    print(a * b, 10);
    print(a / b, 10);
    print(a % b, 10);

Parentheses

BNF for parentheses:

    <paren> ::= "(" <expr> ")"

Example:

    i32 a = 2;
    i32 b = 3;
    print((a + b) * 2, 10);

Type casting

BNF for type casting:

    <cast> ::= "(" <type> ")" <expr>

Example:

    i32 a = 2;
    i8 b = (i8)a;
    print(b, 10);

Octal support

BNF for octal support:

    <octal> ::= "0" <octal>
             | "0"

Example:

    i32 a = 010;
    print(a, 10);

Hexadecimal support

BNF for hexadecimal support:

    <hex> ::= "0x" <hex>
           | "0x" <digit>
           | "0x" <letter>

Example:

    i32 a = 0x10;
    print(a, 10);

Sizeof operator

BNF for sizeof operator:

    <sizeof> ::= "sizeof" "(" <type> ")"

Example:

    print(sizeof(i32), 10);
    print(sizeof(i8), 10);
    print(sizeof(i32*), 10);
    print(sizeof(i8*), 10);

Compiler directives

Custom Label Names

    // Strings
    print("Hello" [hello_string], 10);
    // if statements
    if [if_statement] (a == 2) {
        print("a is 2", 10);
    } else {
        print("a is not 2", 10);
    }
    // while loops
    while [while_loop] (a < 10) {
        print(a, 10);
        a = a + 1;
    }
    // for loops
    for [for_loop] (a = 0; a < 10; a++) {
        print(a, 10);
    }
    // switch
    switch [switch_statement] (a) {
        case [case_1] 1:
            print("a is 1", 10);
            break;
        case [case_2] 2:
            print("a is 2", 10);
            break;
        default [default_case]:
            print("a is not 1 or 2", 10);
            break;
    }
    

Exit Function

BNF for exit function:

    <exit> ::= "exit" "(" <expr> ")"

Example:

    exit(0);