writing printf-like functions for Zilog ZEUS System 8000 - help needed

[dag at per2.UUCP]

I am trying to port a large set of C programs to my Zilog Zeus (Unix SysIII)
system, and have run up against a problem that I hope someone may be able
to help me out with.

The C compiler on this machine takes advantage of the "large" number of
registers in the Z8001 CPU when passing parameters.  Some parameters get
passed in the registers, the rest on the stack.  The system manuals contain
information as to the register allocation algorithm and include a sample
C function which is supposed to take arbitrary argument lists (ala printf),
but the code apparently did not make it through troff unmunged, and several
"#define"s ended up with a value of 0.  So far, I've been unable to figure
out what the values of these defines are supposed to be.  The system also
came with the file /usr/include/varargs.h, but there is no mention of it in
any of the docs, and the definitions in it appear to assume that all the
arguments are on the stack.

Many (most) of the useful tools available over comp.sources.{unix,misc}
contain printf-like functions.  I need to modify these functions for this
system.  I don't know how.  I'm reduced to multiple functions and/or
rewriting large portions of the function-calls to contain much of the
functions code.

If anybody has a C code example of a printf-like function that works on
a Zilog "Zeus" system, please send me E-mail.  A vsprintf implementation
for this machine would be most helpful (as most of these printf-like
functions pass most of the parameters to sprintf, fprintf or printf.)

Note:	I know how to do this on a PDP-11, VAX, i80x86, m68000, ...
	I know the C language quite well.  I don't need a tutorial in
	writing C code.

Thanks in advance --
					Daniel A. Glasser
					...!uwvax!per2!dag
---
 _____________________________________________________________________________
    Daniel A. Glasser                           One of those things that goes
    uwvax!per2!dag                              "BUMP!!!(ouch)" in the night. 
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