Help needed: Porting IRAF to s390

Hi,

since a while, I am working to bring the IRAF package [1] into Debian
[2]. I'd like to make the package working on as many Debian platforms as
possible.

The major problem here is that IRAF needs a small piece of assembler
code that provides a (sort of) setjmp() to their Fortran variant.

A "C" implementation for this looks like:

#include <setjmp.h>

int zsvjmp_( long *buf, long *status ) {
  *status = 0;
  ((long **)buf)[0] = status;
  return sigsetjmp ((void *)((long **)buf+1),0);
}

however this does not work, since the "sigsetjmp" call needs to be
replaced by a jump to sigsetjmp instead.

As example, I show here the assembler for x86-64 (from the IRAF sources):

        .globl	zsvjmp_	
        .type zsvjmp_, @function
zsvjmp_:
        movq %rsi, (%rdi) # store &status in jmpbuf[0]
        movl $0, (%rsi)   # zero the value of status
        addq $8, %rdi     # change point to &jmpbuf[1]
        movl $0, %esi     # change arg2 to zero
        jmp __sigsetjmp   # let sigsetjmp do the rest
       .section        .note.GNU-stack,"",@progbits

The "zdojmp" counterpart is a portable C function.

I created a small tar file that contains the assembler I collected so
far as well as two test programs. The function of the Fortran test
program is still not so important since IRAF uses its own Fortran
calling interface.

Since I have no experience with mips and mipsel machines and no glue at
all for their assembler and the (C) calling conventions: could someone
help me here?

Best regards

Ole

[1] http://http://iraf.noao.edu/
[2] http://bugs.debian.org/690531