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From: vjs@rhyolite.wpd.sgi.com (Vernon Schryver)
Newsgroups: comp.arch
Subject: Re: The CPU with 3 brains---486 compatibility with 8008
Message-ID: <74627@sgi.sgi.com>
Date: 9 Nov 90 19:39:45 GMT
References: <42737@mips.mips.COM> <1990Nov4.014901.23819@zoo.toronto.edu> <9333@b11.ingr.com>
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In article <9333@b11.ingr.com>, lhughes@b11.ingr.com (Lawrence Hughes) writes:
> ...[long flame at INTEL, 8086's and ASM86]...

While the 8086 is far from wonderful in 1991, it was not bad in the late
1970's.  Some people preferred technical features of other machines, but
there were sound business reasons for many to choose the 8086.

I liked the typing of AMS86.  It made the irregularities of the instruction
set easier to stomach, allowing the assembler to make better guesses about
which of the zillion varients of opcodes you meant.  I conjecture that many
of the strong feels about the 8086 instruction set come from those who used
the Microsoft and similar assemblers.

It was nice knowing that when I typed `MOV AX,FOO`, the assember would
notice if I probably meant `MOV AL,FOO`.  ASM86 was no more strongly typed
than C, because it had 'casts' in the form of "type PTR FOO".  Just as in
C, if you wanted to abuse things, all you had to do was say so.  (The many
bugs in the PTR operator are irrelevant to the concept.)  No one today says
C is too strongly typed, and many are in favor of ANSI-C.

Among 100's of K of ASM86 code that were committed, at my hands or at my
direction in previous lives, was a translation of the 1979 vintage
Microsoft BASIC system, from its largely ASM85 source using AMS86
"codemacros." It was easy, effective, and fast to write a set of
codemacros, relying on the "typing" of ASM86 that did better than CONV86.
I never understood why INTEL wrote the strange CONV86 thing--well, I
understand, but don't sympathize.

Anyone who wanted an un-typed version of ASM86 could have easily whipped up
a set of permisive codemacros.


(sorry for the language babble in comp.arch).



Vernon Schryver,    vjs@sgi.com