curvefit question

[Mike Barker <animals(at)wam.umd.edu>]

Hello,

I would like to fit the following function:

y = m2*(x - x0) + m1*x0 + b1

where m2 is the ONLY parameter to be fitted and m1, b1, x0 are
variables (I DO NOT want to fit them).  I'm having trouble figuring out
how to do this with curvefit (or any of the other built-in
routines).  Curvefit won't let me pass m1, b1, and x0 as parameters.  I
tried using a common block to store the variables but I still have to
compile the function before I declare the common block.  If anyone could
help I would be forever grateful.

Sincerely,
Mike