As the article notes, DEC's OSes largely dodged the bullet by having good workarounds and in-kernel implementations for the missing instructions.
Open-source VAX OSes weren't so lucky. BSD's libm used EMOD pretty heavily (for modf() and the like), and this caused problems in unexpected places if you happened to be running on a newer machine that didn't have these instructions (stuff like: awk would crash!). So the OSes had to follow suit as well, at least for the instructions that libraries / compilers would emit (which fortunately excluded most uses of the G and H floating types). The documentation available at the time was okay but.. imprecise.
Open-source VAX OSes weren't so lucky. BSD's libm used EMOD pretty heavily (for modf() and the like), and this caused problems in unexpected places if you happened to be running on a newer machine that didn't have these instructions (stuff like: awk would crash!). So the OSes had to follow suit as well, at least for the instructions that libraries / compilers would emit (which fortunately excluded most uses of the G and H floating types). The documentation available at the time was okay but.. imprecise.
source: I wrote the EMOD implementation for OpenBSD/vax a long time ago; POLY had already been done by NetBSD. It's still there! http://cvsweb.openbsd.org/cgi-bin/cvsweb/~checkout~/src/sys/...