Re: New target porting time estimates?

[Ian Lance Taylor <ian at wasabisystems dot com>]

Richard Tierney <mfoc73@dsl.pipex.com> writes:

> Hi - can anyone give me any opinions on how long it'll take to port
> GCC and binutils to a new architecture? This is a medium-complexity
> RISC-ish processor. I know this is a 'how long is a piece of string'
> question, but any estimates would be much appreciated. I've spent a
> couple of hours on the web looking for answers but had no luck.

I would say that there are two major variables here.

First, how similar is the processor to other processors which gcc
already supports?  If the processor has unique features, then it may
take more time to figure out how to make gcc handle those features.
If the processor is just like other processors, then why bother
building it--er, I mean, it will be easier to do the gcc port.

Second, how familiar is the person or people doing the port with
working on gcc, and how much experience do they have developing new
ports?  And, bluntly, how good are they as programmers?  A gcc port is
not (yet) a task for a mediocre programmer, at least not one without a
lot of guidance.  Software is still a field where professional
programmers can differ in quality by a full order of magnitude, a fact
which is not true of most engineering disciplines.

I think that when I was at Cygnus, we usually figured that one
experienced programmer could do a complete gcc and binutils port for a
fairly typical processor in three to four months.  This would be a
person who had already done extensive work on gcc and the binutils,
and who was working next to and had immediate access to most of the
top experts on the gcc and binutils code.

On the other hand, if we are talking about a non-expert programmer,
with no experience on gcc and the binutils, relying on the public
mailing lists for help, I think it would take a good dose of luck and
perseverance for the port to ever be finished at all.

I think I'm telling it like it is, but I should also reveal my bias by
saying that my employer, Wasabi Systems, will do this type of work for
pay.  There are several other companies and consultants, well
represented on these mailing lists, which you can also hire for this
type of work.

Hope this helps.

Ian