PRIME pointer sizes

[Peter N. Wan]

Aha....  I knew there was an article that I wanted to respond to, but
couldn't find it in my stack of printouts.  There are two C language
compilers available for Prime machines that I am aware of.  The first
one is the one put out by Prime Computer (it was originally from Primarily
Software, Inc., I believe).  This compiler does indeed use different-sized
pointers (48-bit pointers consist of a segment number, word offset within
that segment, and then a bit specification in the field address registers).
Their 32-bit pointers are just the segment number and word offset.  The
other compiler is the one licensed by the School of ICS at Georgia Tech
with their Software Tools implementation for Primes.  This compiler
generates 32-bit pointers (character arrays are stored one character per
word).  Since I have not worked much with the Prime C compilers, I had to
ask one of our Prime gurus about the preceding; a rather short disassembly
session yielded the above information.  I don't know if other code might be
generated for cases such as struct pointers, etc.
-- 
Peter N Wan
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