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From: Michael S <already5chosen@yahoo.com>
Newsgroups: comp.arch
Subject: Re: is Vax addressing sane today
Date: Tue, 10 Sep 2024 12:08:40 +0300
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On Tue, 10 Sep 2024 07:43:53 GMT
anton@mips.complang.tuwien.ac.at (Anton Ertl) wrote:

> Brett <ggtgp@yahoo.com> writes:
> >Speaking of complex things, have you looked at Swift output, as it
> >checks all operations for overflow?
> >
> >You could add an exception type for that, saving huge numbers of
> >correctly predicted branch instructions.
> >
> >The future of programming languages is type safe with checks, you
> >need to get on that bandwagon early.  
> 
> MIPS got on that bandwagon early.  It has, e.g., add (which traps on
> signed overflow) in addition to addu (which performs modulo
> arithmetic).  

Trapping variants were deprecated in Release 6 of MIPS ISA.

>>It has been abandoned and replaced by RISC-V several
> years ago.

I don't think that "replaced by RISC-V" is a correct description of
proceedings.

> 
> Alpha got on that bandwagon early.  It's a descendent of MIPS, but it
> renamed add into addv, and addu into add.  It has been canceled around
> the year 2000.
> 
> RISC-V, another descendent of MIPS, has an add instruction that
> corresponds to MIPS' addu, and no instruction that corresponds to
> MIPS' add.  They obviously don't think that there's a bandwagon.  Note
> that RISC-V was designed after Swift was introduced.
> 
> IA-32 got on that bandwagon early.  It has a single-byte instruction
> trapv that traps if the overflow flag is set.  The AMD64 instruction
> set is very similar to the IA-32 instruction set, but one of the few
> differences is that the trapv instruction was eliminated, and the
> encoding replaced with a REX prefix.  The AMD64 architects obviously
> don't think that there is a bandwagon.
> 
> Apple has been designing their own silicon for a while, and they have
> introduced Swift as their language in 2010.  Yet they have not
> switched to an architecture like MIPS or Alpha, nor have they designed
> their own architecture or architecture extension that includes
> instructions like Alpha's addv or IA-32's trapv.  Instead, they
> switched to ARM A64, which does not have such features, after
> introducing Swift in 2010.  They obviously don't think that there is
> such a bandwagon, either.
> 
> - anton


How does Intel MPX fit in your picture?