Re: Hardware Design supporting Ada

[Shark8 <onewingedshark@gmail.com>]

On Sunday, December 11, 2016 at 2:15:18 PM UTC-7, Niklas Holsti wrote:
> 
> Did they mention the Nokia MPS-10:
> 
> http://dl.acm.org/citation.cfm?id=989799&dl=ACM&coll=DL&CFID=874929794&CFTOKEN=55213355
> 
> http://computer-programming-forum.com/44-ada/596b4e2f57763ce6.htm

No, but thank you for the information there!
It looks really interesting -- the MPS-10 along w/ the R-1000 makes it seem like while a considerable effort, HW (and OS) designed for (and programmed in) Ada is a good choice for reliability and maintainability.

> > In addition to this, I've been doing some work looking into
> > balanced-ternary computers ...
>  > Further, [balanced] ternary provides some interesting properties;
>  > if,for example, we define {1, 0, -1} as {greater-than, equal,
>  > less-than} respectively then we can have a JUMP instruction
>  > that takes this single Trit comparison result and three offsets
>  > and take care of ALL the JUMP combinations in binary instruction
>  > -sets with one instruction.
> 
> Then you will be able to implement the original FORTRAN "arithmetic 
> IF-statement" very efficiently, it being of the form
> 
>     IF (expr) 100, 200, 300
> 
> which would pass control to the label 100 if the expression in the 
> parenthesis is negative, to 200 if it is zero, and to 300 if it is positive.
> 
> However, I don't see how such an instruction would help Ada, in particular.

That's true, it /would/ have a more natural mapping to FORTRAN in this case. But, OTOH, Ada's always been of the mindset that the compiler should handle little optimizations like that. (On a semi-related note, the implementation of ternary search-trees would be simple.)

You, and others here, might be interested in this manual on the iAPX 432's proposed extensions to Ada:
http://bitsavers.trailing-edge.com/pdf/intel/iAPX_432/172283-001_Reference_Manual_for_the_Intel_432_Extensions_to_Ada_Dec81.pdf

These extensions mapped to and "conveniently expose[s] the concepts and capabilities of the iAPX 432."