Help needed: small piece of assembler code for IRAF

Dear m68k enthusiasts,

I am the maintainer of the "iraf" package [1]. Although most of the code 
is portable, it needs one piece of assembler code for each platform that 
provides a (sort of) setjmp for FORTRAN.

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 IRAF is a 40-year old package, there was already some assembler that 
was used ~35 years ago [2]:

-------------------------------8<-----------------------------------
         .text
         .globl  _zsvjmp_

         JMPBUF	=       4
         STATUS  =       8

_zsvjmp_:			|# CALL ZSVJMP (JMPBUF, STATUS)
         movl    sp@(JMPBUF),a0	|# set A0 to point to jmp_buf
         movl    sp@(STATUS),a1	|# A1 = status variable
         movl    a1,a0@		|# JB[0] = addr of status variable
	clrl	a1@		|# return zero status
	addql	#4,sp@(JMPBUF)	|# skip first cell of jmp_buf
         jmp     _setjmp		|# let setjmp do the rest.
-------------------------------8<-----------------------------------

However, just including this does not work because assembler syntax 
changed [3].

I created a small repository [4] that contains the assembler I collected
so far as well as two test programs.

As I am not familiar with m68 assembler I have no idea how to adopt the 
assembler code. Maybe someone could help me here? Preferably under the 
IRAF license [5], so that it can be included upstream later.

One way that worked for other platforms was to compute the C snipped 
above (having the sigsetjmp function name by something else) with an 
optimizing compiler.

There is no request from the users to have this ported to m68k, and I
doubt that ever will. My main motivation to get it ported is to check
the package for hidden problems on "unusual" architectures.

Best regards

Ole


[1] https://tracker.debian.org/pkg/iraf
[2] 
https://github.com/iraf-community/iraf/blob/v2.16.1/unix/as.mc68020/zsvjmp.s
[3] 
https://buildd.debian.org/status/fetch.php?pkg=iraf&arch=m68k&ver=2.18.1%7Erc1-3%7E2&stamp=1726682343&raw=0
[4] https://github.com/olebole/zsvjmp
[5] https://iraf-community.github.io/COPYRIGHT.html