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Analysis of Amiga Virtual Processor ASM
An anonymous reader sent us an analysis
of the new Amiga Virtual Processor assembly Language -- unlimited registers, register naming, high-level looping constructs, a tool-based architecture, and object-based assembly programming,
complete with some cool examples.
This article doesn't really convey the point of the Tao Group's technology. Sure its a nifty assembler, but programmers middle aged and above will remember that assemblers used to be very much like this back when humans used them. Thats not new. (Dang whippernappers always thinking they're inventing repiration.)
:-)
The point behind the Tao stuff is that all of your code is built to the virtual assembly language and shipped as the virtual machine code. It is translated to local machine code as needed on the target system (and cached as appropriate for that system, eg. once forver to disk for desktop PCs).
This means one version of the application that runs on any (supported) target processor. It also means your final executable code is optimized for your particular processor, say K7 instead of just generic IA32 instruction set.
Tao has been add this since at least 1995, maybe earlier. They have good technology. Maybe its even useful.
Ever look at the size of the average C compiler? The executable is huge, it involves all sorts of passes from external programs, and runs like a dog. Writing a straightforward and simple C compiler, like Small C (which had the source code published in a thin book over fifteen years ago), isn't too bad. But C hasn't scaled well. It has gotten out of control.
The VP was designed to be simple to translate to real machine code, and have good speed of execution. It's a definite balance. Remember, VP code is translated to machine code on the *fly*. You wouldn't want to have to run a C compiler every time you started an application, would you?
Here's another way of thinking about it. In the mid 1980s, the average PC C compiler fit on a 360K floppy disc and worked in 640K memory. I remember Amiga C compilers than ran fine in 512K on the original 7+ MHz processor. But now you can't get enough processor power to compile. gcc and Visual C++ and CodeWarrior just eat up the cycles like there's no tomorrow. Then there are compilers like Borland's Object Pascal that are hitting 1,000,000 lines per minute on old hardware. Going with the VP over C was a good choice. It gets away from a lot of C baggage that we like to pretend doesn't exist.
Amiga has always been ahead of the curve. I remember back in 89 or so having to write a serial-based communications program that talked between a VAX (running VMS) and an Amiga.
Thought the VMS part would be easy and the Amiga a pain of stupid little PC-like low-level calls.
Well, it was the opposite. VMS required me to learn QIO calls that had 13 parameters each, and took about 200 lines of code.
The Amiga side was about 50 lines of code and was basically a simple wrapper around the firmware routines that already did everything I wanted. They had tripple-indirect semephores in firmware on a dinky little game platform in the 80s. I hear the UNIX port was nice as most of the low-level including task management, VM (much more than just page tables), and many other features were all in hardware.
Nice box, hope they do as well with the new one!
"...unlimited registers, register naming, high-level looping constructs, a tool-based architecture, and object-based assembly programming,..."
Unless Amiga has made some serious changes to the processor as we know it, I dont necessarily think that this is a good thing. High level looping constructs? The reason that we code in ASM (when we HAVE to) is that it runs very quick. With these higher level capabilities, I am curious as to whether this will slow down the speed.
While I think this would be a cute idea, I am not ready to accept these new gifts if they would cause the purpose of ASM coding -- speed -- to fall short. Has anyone heard of any bench marks or information as to how these higher level capabilities could effect the speed of ASM?