Calling conventions for unprototyped subroutines?

[Mattia Barbon]

  Hello,
crrently argument count is passed in I3. A comment in untils.c
near foldup says that:

    TODO - IMCC and PDD 3 aren't yet in conformance. This uses the current
    IMCC setup, but should be changed as soon as IMCC modified to the
    correct calling conventions.

while pdd03 says:

    ...

    0 if all the parameters are jammed in P registers and the overflow
    array, with a count of parameters passed in PMC registers

so: where is the argument count passed? Please note that I3 is also
mentioned in compiler FAQ.

Thanks!
Mattia