Dear arm64 specialists,
I just got the "IRAF" package accepted into Debian [1]. Although the
code is claimed to be portable, it needs a piece of assembler
code for each platform 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.
I already wrote that code for the arm 32 bit platforms, which looks like
this:
-------------------------------8<-----------------------------------
.file "zsvjmp.s"
.arch armv6
.text
.global zsvjmp_
.type zsvjmp_, %function
zsvjmp_:
mov r2, #0 @
str r2, [r1, #0] @ *status = 0
str r1, [r0, #0] @ buf[0] = status
add r0, r0, #4 @ &buf[1] --> 1st arg for sigsetjmp
mov r1, #0 @ 0 --> 2nd arg for sigsetjmp
b __sigsetjmp @ call sigsetjmp
-------------------------------8<-----------------------------------
The "zdojmp" counterpart is a portable C function.
I created a small repository [2] 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.
However, I have no idea how to write the same for the 64-bit platform
arm64 (the code in the repo does not work). Maybe someone could help me
here? Preferably under the IRAF license [3], so that it can be included
upstream later.
The arm platforms are specifically important for IRAF, since the package
is also used by semiprofessional astronomers who use a Raspberry Pi (and
similar) as observation platform, and there is some request to have IRAF
available there.
Best regards
Ole
[1] https://tracker.debian.org/pkg/iraf
[2] https://github.com/olebole/zsvjmp
[3] https://github.com/iraf/iraf-v216/blob/master/local/COPYRIGHTS
