Compiler

A simple compiler for a subset of the C Programming Language

Usage

1. Keep your input file inside the 'input' folder

2. Run commands.sh, it will prompt you to provide the 'C' file name. This compiles your input file, checks compile errors (lexical/syntax/symantic) and outputs to console and also the logs inside the 'logs' folder. In case of a successful compilation,the generated assembly code can be found exactly where the input file was kept.**

3. Use debug.sh to use gdb

4. Use run_tests.sh to execute predefined tests inside the tests folder

Known Issues

This implementation of compiler uses static allocation and therefore, doesn't support Recursion.

Sample Output

Input C code:

int f(int a){
    return 2*a;
    a=9;
}

int g(int a, int b){
    int x;
    x=f(a)+a+b;
    return x;
}

int main(){
    int a,b;
    a=1;
    b=2;
    a=g(a,b);
    println(a);
    return 0;
}

Generated x86 Assembly

.model small
.stack 100H
.data 
f_return dw ?
a2 dw ?
t0 dw ?
t1 dw ?
t2 dw ?
g_return dw ?
a3 dw ?
b3 dw ?
x3 dw ?
t3 dw ?
t4 dw ?
t5 dw ?
main_return dw ?
a4 dw ?
b4 dw ?
t6 dw ?
t7 dw ?
t8 dw ?
t9 dw ?
.CODE
f PROC
	push ax
	push bx 
	push cx 
	push dx
	push a2
	mov t0,2
	mov ax,t0
	mov BX,a2
	mul BX
	mov t1, ax
	mov f_return,ax
	jmp L_Return_f
	mov t2,9
	mov ax,t2
	mov a2,ax
L_Return_f:
	pop a2
	pop DX
	pop CX
	pop BX
	pop ax
	ret
f ENDP
g PROC
	push ax
	push bx 
	push cx 
	push dx
	push a3
	push b3
	push x3
	mov ax,a3
	mov a2,ax
	call f
	mov ax,f_return
	mov t3,ax
	add ax,a3
	mov t4,ax
	add ax,b3
	mov t5,ax
	mov x3,ax
	mov g_return,ax
	jmp L_Return_g
L_Return_g:
	pop x3
	pop b3
	pop a3
	pop DX
	pop CX
	pop BX
	pop ax
	ret
g ENDP
main PROC
	mov ax,@DATA
	mov ds,ax 

	mov t6,1
	mov ax,t6
	mov a4,ax
	mov t7,2
	mov ax,t7
	mov b4,ax
	mov ax,a4
	mov a3,ax
	mov ax,b4
	mov b3,ax
	call g
	mov ax,g_return
	mov t8,ax
	mov a4,ax
	call OUTDEC
	mov t9,0
	mov ax,t9
	mov main_return,ax
	jmp L_Return_main
L_Return_main:
	mov ah,4CH
	int 21H
OUTDEC PROC  
            push ax 
            push bx 
            push cx 
            push dx  
            cmp ax,0 
            jge BEGIN 
            push ax 
            mov DL,'-' 
            mov ah,2 
            int 21H 
            pop ax 
            neg ax 
            
            BEGIN: 
            xor cx,cx 
            mov bx,10 
            
            REPEAT: 
            xor dx,dx 
            div bx 
            push dx 
            inc cx 
            or ax,ax 
            jne REPEAT 
            mov ah,2 
            
            PRINT_LOOP: 
            pop dx 
            add DL,30H 
            int 21H 
            loop PRINT_LOOP 
            
            mov ah,2
            mov DL,10
            int 21H
            
            mov DL,13
            int 21H
        	
            pop dx 
            pop cx 
            pop bx 
            pop ax 
            ret 
OUTDEC ENDP 
END MAIN