Title: ASM-DSL
Date: 2017-03-11T00:00:00
Tags: CS231, Assembly, DSL
Authors: Henry Brooks

I have been thinking about all of the boilerplate code that I keep writing in my assembly class and I decide to start looking into creating a simple DSL to assist with my code writing.

Mostly I am looking to simplify code blocks that have easy c++ analogs. Specifically cin, cout, and assignment (=).

Currently I am writing code like this

example.asm

...
#------ cin << $s0
li	$v0, 5
	syscall
	add	$v0, $s0, $0

#------ $s1 = $s0
        add	$s1, $s0, $0

#------ cout << $s1
	li	$v0, 1
	add	$a0, $s1, $0
	syscall
...

To get results for code like this in c++

example.cpp

...
int s0, s1;
cin >> s0;
s1 = s0;
cout << s1;
...

I recognize that there are some actions that need a full compiler to implement however, I think that I can implement this much in typed/racket with what I already know. I’m choosing to use typed/racket because I want to experiment with using it and I think it will come in useful if I continue to expand the scope of the code.

ASM-DSL.rkt

#lang typed/racket

;; Save register values
(define func "$v0")
(define return "$v0")
(define input "$s0")
(define arg "$a0")
(define zero "$0")

;; Buildin MIPS instructions
(define (comment [s : String])
  (display (string-append "#------ " s "\n")))

(define (add [x : String] [y : String] [z : String])
  (display (string-append "\tadd\t"
                          x ", "
                          y ", "
                          z "\n")))

(define (li [x : String] [y : Integer])
  (display (string-append "\tli\t"
                          x ", "
                          (number->string y) "\n")))

(define (syscall)
  (display "\tsyscall\n"))

;; Macros I built
(define (set-reg [x : String] [y : String])
  (add x y zero))

(define (cout-int [x : String])
  (comment (string-append "cout << " x))
  (li func 1)
  (set-reg arg x)
  (syscall)
  (display "\n"))

(define (cin-int [x : String])
  (comment (string-append "cin << " x))
  (li func 5)
  (syscall)
  (add return x zero)
  (display "\n"))

;; Mips code
(cin-int "$s0")
(set-reg "$s1" "$s0")
(cout-int "$s1")

output.asm

#------ cin << $s0
	li	$v0, 5
	syscall
	add	$v0, $s0, $0

	add	$s1, $s0, $0
#------ cout << $s1
	li	$v0, 1
	add	$a0, $s1, $0
	syscall