Re: Compile HLL to microcode on VLIW - possible?

"Alaric B. Williams" <alaric@abwillms.demon.co.uk> writes:
> Most 'situations', be they languages or operating systems, that impose
> a paradigm have these special situations that would benefit immensely
> from one or two special opcodes, installed once and for all. When
> microcode alteration becomes practical to the level where it is
> customised by the compiled for the code being produced, even more good
> stuff can result!


> [I've used systems with completely customizable microcode. They ran
> as though stapled to a snail. -John]


Me too! In fact, Data General had a project during the late 70s and
early 80s to produce such a system. I was working at DG at the time
and watched this system progress from a dream to a fiasco.
Originally, it was to have customizable microcode that would be
tailored to each programming language and to the kernel. Trouble was,
every system call then resulted in two (very expensive) switches
between microcode sets. Took 20 minutes (no kidding!) to run the
Hello world program! Made snails look like speed demons!


To make a long story short, they gradually scaled back the
customizable parts until there was virtually nothing left, but by then
the project was hopelessly behind in technology and way over budget.
I think they may have actually shipped a few machines for database
applications, but it certainly was not a success.


--
Bill Leonard
Harris Computer Systems Corporation
2101 W. Cypress Creek Road
Fort Lauderdale, FL 33309
Bill.Leonard@mail.hcsc.com
--

Return to the comp.compilers page.
Search the comp.compilers archives again.