HLA – The High Level Assembly Programming Language

    October 18, 2005

I’ve noted before that assembly language programming can be quite engrossing. It’s the level of detail that captivates; there can be a great deal of craftmanship and mental challenge in writing assembly programs.

However, the required detail can also be annoying and the source of much boredom, particularly when you are working in the areas that aren’t really of interest to you, like simple screen output. It’s the drudgery that turns most of us to higher level languages.

The juxtaposition of “high level” and “assembly” is a cause for raised eyebrows. Usually the approach to the “I don’t want to write that part” is handled by libraries, but HLA comes at it as its own language.

Originally desgned for teaching, the concept was to allow students familiar with C or Pascal to get a running start by being able to use similar constructs. A quote from HLA’s creator, Randy Hyde:

HLA lets students write meaningful programs within about a week of it’s introduction (e.g., the first assignment I gave last quarter was to write an “addition table” program that computes the outer product [addition table] of the two vectors 0..15 and 0..15, printing the table formatted nicely). They achieve this by using statements they already know (like IF and WHILE) with the injection of just a few assembly language concepts (registers, and the MOV and ADD instructions) plus an introduction to the HLA Standard Library.

Over the next several weeks, these students write more and more complex programs as they are introducd to new assembly language and HLA concepts (e.g., data representation, basic architecture, addressing modes, data types, and additional instructions). At about the sixth week, I begin “weaning” these students off the high level language statements and force them to use the low level machine instructions. It turns out that they learn how to simulate an IF statement at roughly the same point in the quarter as they did when they used only MASM, but the big difference is that they’ve written a lot more code up to that point proving out other concepts in machine organzation and assembly language programming.

If you are already an assembly programmer, you probably won’t like HLA: remember, it was desigened to teach, and to feel like a higher level language. But if you just like to dabble, this could be fun.

*Originally appeared at APLawrence.com

A.P. Lawrence provides SCO Unix and Linux consulting services http://www.pcunix.com