SGI IRIX 4.0 to implement presubstitution?

[David Hough]

 From what I can gather from a blurb in their customer support quarterly,
IRIX 4.0 will have a libfpe.a which will enable Fortran programs to write

	fsigfpe(FPE_DIVZERO).repls=FPE_USER_DETERMINED

 ...

	call handle_sigfpes(...userfpe...)

 ...

	subroutine userfpe(exception, value)
	integer exception(0:4)
	real value(2)
	value(1)=9999.0
	return
	end

and this will cause division by zero to be replaced by 9999.0.
It's not clear whether this affects double precision as well as single.

It's also not evident whether you can trap (or even detect) inexact 
exceptions, at least from this brochure.   IRIX 4.0 is not supposed to be
distributed until later this year.

Possibly SGI would send you a copy of the blurb if you ask.  What you want is
the Sept/Oct 1991 issue of Pipeline.   You can try asking at pipelineasgi.com,
or possibly at a SGI sales office.

I don't know whether MIPS, DEC, or CDC have anything similar in their MIPS
ISA products.   When I updated the competitive lab in the Sun 
languages dept.,  I decided that SGI seemed to be pushing the R3000 technology 
hardest desktops - as opposed to servers or future R4000 systems -
so I got Sun to buy a 4D/35.  But a major new OS release ought to set them back
for a while...