Typed Assembly Language (2000)

[estimator7292]

If you're gonna make a website for your programming language, you NEED to put an example of the language front and center on the landing page.

Three links deep and I finally found some code... packaged in a gz archive. I still have not seen a line of TAL

[impl]

This website is at least 25 years old. It uses one of the pre-canned templates from FrontPage 2000. Cut 'em a little slack. :-)

This was obviously someone's research project, and some of the papers have example code in them, e.g. see https://www.cs.cornell.edu/talc/papers/talx86-wcsss.pdf.

[geocar]

> If you're gonna make a website for your programming language, you NEED to put an example of the language front and center on the landing page.

Did you consider the possibility that this sort of thing was done to avoid wasting time with non-experts who think an "example" of a language they don't know is enough to make comments about?

> I still have not seen a line of TAL

My suggestion: Start with the "Papers" and then look at the paper that introduces TAL. It has an example program with analysis

[az09mugen]

Same here, partial code from stackcodegen.ml in the said archive :

open Op;; open Var;; open Ctx;; open Ltal;; open Util;;

let debug msg = ();;

let rs = mkvar "rs";; let ra = mkvar "ra";; let rf = mkvar "rf";; let rt = mkvar "rt";; let rr = mkvar "rr";; let ru = mkvar "ru";;

let retty stackty aty = (Code(Ctx.from_list[(rs,stackty); (ra,aty); (rt,toptp); (rf,listtp); (rr,toptp)]))

let rec tt tctx ctx tp = match tp with Il.TVar a -> if bound tctx a then TVar a else lookup ctx a | Il.Int -> DTp Word | Il.Top -> DTp Top (* for now ) | Il.Tensor(t1,t2) -> Ref(Tcltal.mkpair (tt tctx ctx t1, tt tctx ctx t2)) | Il.Exists (alpha, tp) -> let beta = rename alpha in Exists (beta, W, tt tctx (extend ctx alpha (TVar beta)) tp) | Il.List t -> let tv = mkvar "list" in Mu(tv,NRef(Tcltal.mkpair(tt tctx ctx t, TVar tv))) | _ -> DTp(arrowtt tctx ctx tp)

and arrowtt tctx ctx t = match t with Il.Forall(alpha,t) -> let beta = Var.rename alpha in Forall(beta, W, arrowtt tctx (extend ctx alpha (TVar beta)) t) | Il.Arrow(t1,t2) -> let t1' = tt tctx ctx t1 in let t2' = tt tctx ctx t2 in let stk = mkvar "s" in Forall (stk,M, Code(Ctx.from_list[(rs,Stack(Tensor(t1',MTVar stk))); (ra,toptp); (rt,toptp); (rf,listtp); (rr,DTp(retty (Stack(MTVar stk)) t2'))]))

  | _ -> tcfail "expected a function type in forall"

let typetrans tctx tp = tt tctx Ctx.emp tp let arrowtypetrans tctx t1 t2 = arrowtt tctx Ctx.emp (Il.Arrow (t1,t2))

( Need to specify the type ty of "the rest of the stack", in most cases alpha )

type code_env = {cctx : cctx; cs : code_section; fctx : Il.ctx; lctx : var Ctx.ctx; fp : int}

let get_fctx cenv = cenv.fctx let get_lctx cenv = cenv.lctx

type block_env = {cenv : code_env; ilist : instruction list; lab : clab; tctx : Ltal.tctx; rctx : Ltal.rctx}

let get_from_cenv f benv = f benv.cenv

exception CodeFail of string code_env exception BlockFail of string * block_env

(* val begin_fn : code_env -> clab -> register_file -> block_env val end_fn : block_env -> code_env val emit_label : fn_env -> clab -> dtp -> block_env val emit : block_env -> instruction -> block_env -> block_env val emit_end : end_instruction -> block_env -> fn_env val drop : reg -> block_env -> block_env val free : reg -> block_env -> block_env val push : reg -> reg -> block_env -> block_env val pop : reg -> reg -> block_env -> block_env val malloc : reg -> block_env -> block_env )

let do_print y x = (debug y; x)

let (>>) f g x = g(f(x)) let (>>=) f h x = let y = f x in h y x

let rec mkltp tctx rctx = Ctx.fold (fun t sk dtp -> let k = match sk with _,W -> W | _,M -> M in Forall(t,k,dtp)) tctx (Code (rctx))

let current_ltp benv = debug ("Generalizing "^(Ctx.pp_ctx (fun _ -> "") benv.tctx)^"\n"); ( rt is caller-save *) let rctx = update benv.rctx rt toptp in (mkltp benv.tctx rctx)

[addaon]

I think a challenge to me for typing assembly, unless you’re doing old-school C style minimally-useful types, is that assembly types tend to be both more ad hoc and more transient than types in higher level languages, because these types come from the intersection of the problem domain and the way of expressing the solution, instead of just from the problem domain. In C++ I might have a type for “aircraft velocity in mm/s”, but in assembly I might have that type on one line, and then go to velocity in 2x mm/s the next line to save a renormalization; or have types for various state flags, but have them pack differently into a word in different places in the code. This is all expressible, but I think it would make me favor a more implicit typing with a heavier emphasis on deduction, just to minimize the description of types that exist but are not in themselves interesting.

[noduerme]

Just thinking about an aircraft's velocity as a specific type, rather than a vector with three floats, has my mind whirling. I can imagine a lot of terrifying things I wish I didn't think could be added later to that struct in some avionics system. What would you need a type for that for? Am I thinking too high level, where this type might include its own getters and function calls?

[chris_money202]

Feel like this could be the solution to “LLMs will write in binary” Elon was talking about. The problem with it is, assembly is tightly coupled to the hardware, so LLMs might have an easier time generating/understanding context of a “typed” assembly language but now need to understand the hardware and its constraints as part of the context or have it in its training data. I personally just think having that knowledge codified deterministically in the compiler is simpler, but I guess time will tell.

[throwaway27448]

What would be the advantage over generating human-readable code like, say, c? Why not just tell it what hardware you're targeting as part of the prompt?

[leptons]

I feel like this is a solution in search of a problem that was already solved by C.

[geocar]

These "types" are hindley-milner types and have almost nothing to do with what C calls a type.

Your "feelings" may help you make snap judgements that can keep you alive, but they cannot help you code and they will conspire against you when you effort to learn new things. Nobody wants to feel wrong, and you will feel wrong many times when you learn something new, but it is the only way to actually learn the thing. Remember this the next time you have "feelings" about knowledge

[pjmlp]

Except C being typed Assembly is a myth, first of all there were already high level systems languages during the decade that predates C, secondly there are plenty of CPU capabilities not exposed in C, if at all only via compiler specific language extensions, beyond the language standard.

[Surac]

Reinventing C?

[fnky]

You know it's good when all the members have their home addresses listed on their personal websites.

Too bad there's no examples of how this looked like.