Simple Language Compiler to Stack-Based Machine Code

...for fun and education.

Overview

This project is a compiler that translates a simple programming language into stack-based machine code. This compiler was developed as a practical application of concepts learned in my undergraduate Compiler course, drawing inspiration from the specifications outlined in there. It takes source code as input and generates machine instructions that can be executed on a stack-based virtual machine.

Features

• Supports integer arithmetic (+, -, *, /, %)
• Logical and relational operations (and, or, not, <, >, <=, >=, =, <>)
• Conditional statements (if-then, if-then-else)
• Looping via labels and goto statements
• Basic I/O operations (read, print)
• Procedure calls with gosub and return
• Stack-based execution model
• Memory management for variables and labels

Input Language Specification

The compiler processes a high-level structured language with:

• Variable and label declarations (var <IDENT>, label <IDENT>)
• Arithmetic and logical expressions
• Control flow statements (if, goto, gosub, return, begin ... end)
• Program termination via exit

Example input program (Factorial Calculation):

label loop;
var k;
var j;
var i;
read k;
if k > 0 then begin
  j:=1;
  i:=k;
  loop:
    j:=j*i;
    i:=i-1;
    if i > 1 then goto loop;
  print j;
end;

Outputs:

DATA	0,0,0,0,0,0
#	k,j,i,ret,boolSetRet,gp
0	READ
1	POP $0
2	PUSH $0
3	PUSH 0
4	PUSH 9
5	POP $4
6	SUB
7	JGZ $34
8	JMP $38
9	JZ $33
10	PUSH 1
11	POP $1
12	PUSH $0
13	POP $2
14	PUSH $1
15	PUSH $2
16	MUL
17	POP $1
18	PUSH $2
19	PUSH 1
20	SUB
21	POP $2
22	PUSH $2
23	PUSH 1
24	PUSH 29
25	POP $4
26	SUB
27	JGZ $34
28	JMP $38
29	JZ $31
30	JMP $14
31	PUSH $1
32	PRINT
33	STOP
#BoolLabels - setTrue, setFalse
34	POP
35	PUSH 1
36	PUSH $4
37	JMP
38	POP
39	PUSH 0
40	PUSH $4
41	JMP