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Re: Joint Design of Instruction Set and Language

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John Levine <johnl@iecc.com> writes:
> The Berkeley RISC and the SPARC were, in practice if not in theory,
> designed around the PCC C compiler.  The reason they used register
> windows was that PCC wasn't smart enough to minimize register saves.
> The IBM 801, designed at the same time with the much more advanced
> PL.8 compiler had a normal register set and load/store multiple
> since the compiler was able to minimize the number of registers
> to store.

I've commented that John did 801 in re-action to hardware complexity of
the (failed) FS effort
http://www.garlic.com/~lynn/subtopic.html#futuresys

at presention in '76, the 801 group claimed that the hardware
simplification would be traded off against the sophistication of cp.r
operating system and pl.8 compiler.

no hardware domain protection would be compensated by pl.8 compiler only
generating correct code, and cp.r operating system only loading correct
programs. the few number of virtual address segment registers would be
compensated by inline application being able to switch virtual address
segment registers ... as easily as general purpose (address) register
values, can be switched. 801 would also not have any cache consistency
(since 370 & FS had very high penalty for cache consistency).

circa 1980, there was big internal push for migrate large number of
internal microproceessors to 801 (Iliad) ... including lots of
controller microprocessors and the microprocessors used in low-end and
mid-range 370 (aka followon to 4341, the 4381 was originally to be
801/iliad processor). misc. old email mentioning 801, risc, iliad, etc
http://www.garlic.com/~lynn/lhwemail.html#801

when most of those efforts failed, some number of engineers left to do
risc efforts at other companies.

the 801/ROMP was originally going to be for the follow-on to the
displaywriter ... when that effort failed, they looked around and
decided on retargeting for the unix workstation market. as part of that,
the company that had done the AT&T port for pc/ix, was contracted to do
a AT&T port to romp (becoming aixv2). hardware protection domain was
also needed in romp for transition from cp.r to unix. misc. past posts
mentioning 801, risc, romp, rios, power, power/pc, etc
http://www.garlic.com/~lynn/subtopic.html#801

for fun of it ... old email about request for 801 by LISP machine group:
http://www.garlic.com/~lynn/2003e.html#email790711
in this post (with several other old 801 emails)
http://www.garlic.com/~lyynn/2003e.html#65 801

-- 
virtualization experience starting Jan1968, online at home since Mar1970

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Joint Design of Instruction Set and Language jsavard@excxn.aNOSPAMb.cdn.invalid (John Savard) - 2011-07-15 00:24 +0000
  Re: Joint Design of Instruction Set and Language nmm1@cam.ac.uk - 2011-07-15 08:36 +0100
    Re: Joint Design of Instruction Set and Language Bill Findlay <yaldnif.w@blueyonder.co.uk> - 2011-07-15 18:05 +0100
  Re: Joint Design of Instruction Set and Language anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2011-07-15 08:14 +0000
    Re: Joint Design of Instruction Set and Language John Levine <johnl@iecc.com> - 2011-07-15 10:32 +0000
      Re: Joint Design of Instruction Set and Language Anne & Lynn Wheeler <lynn@garlic.com> - 2011-07-15 10:18 -0400
      Re: Joint Design of Instruction Set and Language anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2011-07-15 16:30 +0000
        Re: Joint Design of Instruction Set and Language Anne & Lynn Wheeler <lynn@garlic.com> - 2011-07-15 14:26 -0400
    Re: Joint Design of Instruction Set and Language torbenm@diku.dk (Torben Ægidius Mogensen) - 2011-07-15 14:26 +0200
      Re: Joint Design of Instruction Set and Language Terje Mathisen <"terje.mathisen at tmsw.no"> - 2011-07-15 15:59 +0200
    Re: Joint Design of Instruction Set and Language jsavard@excxn.aNOSPAMb.cdn.invalid (John Savard) - 2011-07-15 13:48 +0000

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