ARM C Compiler (ACC)

ACC is a pet project with the purpose of improving my knowledge of three topics. The C language, compilers and the ARM assembly. I think this is a good exercise to go deep into both topics.

The ACC is a LALR(1) parser, that means it is a Look-Ahead Left-to-Right parser.

The current Grammar of the ACC is the following:

S -> int main "(" ")" "{" E "}"
E -> return I;
     | if "(" B ")" "{" E "}"
     | if "(" B ")" "{" E "}" else "{" E "}"
I -> [0-9]+
B -> I < I
     | I <= I
     | I == I
     | I >= I
     | I > I
     | ! B
     | "(" B ")"

Future work for the project

1. Main function
2. Return statement
3. Int value
4. Boolean operations
5. Conditionals
6. Variable (int)
7. Addition and substraction operations
8. Multiplication and division operations
9. Comments
10. Functions
11. String
12. Array
13. Pointer
14. Struct
15. Loop
16. Include
17. …
18. Self-contained Compiler

Example of the usage of the ACC

C code:

int main()
{
    if (1 < 2)
    {
	    if (4 > 10)
	    {
		    return 1;
	    }
	    else {
		    return 2;
	    }
    }
    return 0;
}

Assembly generated:

	.text
	.global main
main:
	mov r0, #1
	mov r1, #2
	cmp r0, r1
	bge if_else_0
	mov r0, #4
	mov r1, #10
	cmp r0, r1
	ble if_else_1
	mov r0, #1
	bx lr
if_else_1:
	mov r0, #2
	bx lr
if_else_0:
	mov r0, #0
        bx lr