https://gcc.gnu.org/bugzilla/show_bug.cgi?id=70220
--- Comment #5 from Wink Saville <wink at saville dot com> --- (In reply to H.J. Lu from comment #4) > (In reply to Wink Saville from comment #0) > > I'm using the new C interrupt attribute for x86 and its working well. But > > when I expanded its use to include handling thread context switches, I found > > that its current implementation lacking. > > > > When using an ISR for a thread context it is necessary to save and restore > > all registers but by default it saves a few as it thinks are necessary. It > > is possible to use the clobber list of inline assembly to tell the interrupt > > attribute code to save additional registers but you can't seem to mention > > the segment registers in that clobber list, thus to save these additional > > registers you must manually save them manually. > > > > Compiler doesn't use segment registers, except for TLS, which should > be used in ISR. ISR needs to save and restore any registers, which > aren't used by compilers, if they are changed in ISR. Is there a definitive list of the registers that the compiler uses and their purpose? I did some searches but didn't come up with any good answers.
