Re: Embedded languages based on early Ada (from "Re: Preferred OS, processor family for running embedded Ada?")

[Martin Thompson <martin.j.thompson@trw.com>]

Colin Paul Gloster <Colin_Paul_Gloster@ACM.org> writes:

> I post from news:comp.lang.ada to news:comp.lang.vhdl .
>

I'll leap in then :-)

> Stephen A. Leake wrote in news:news:u649rx29a.fsf@stephe-leake.org on
> news:comp.lang.ada for the benefit of Mike Silva:
>
> "[..]
>
> [..] FPGA development relies heavily on simulation,
> which does not require real hardware."
>
>
> A warning to Mike Silva: supposed simulators for languages chiefly
> used for FPGAs often behave differently to how source code will
> actually behave when synthesized (implemented) on a field programmable
> gate array. This is true of cheap and expensive tools promoted as
> simulators.
>

What do you mean by this?  The VHDL I simulate behaves the same as the
FPGA, unless I do something bad like doing asynchronous design, or
miss a timing constraint.  These are both design problems, not
simulation or language problems.

<snip>
> " multi-dimensional
> arrays) gave a feeling of clarity and integrity absent from software
> development languages."
>
>
> Apparently for many years, VHDL subset tools (the only kind of VHDL
> tools which exist, so even if the language was excellent one would
> need to restrict one's code to what was supported) used to not support
> multi-dimensional arrays.
>

What's this about "only VHDL subset" tools existing?  Modelsim supports
all of VHDL...  It is true that synthesis tools only support a subset of
VHDL, but a lot of that is down to the fact that turning (say) an
access type into hardware is a bit tricky.

Multi dimensional arrays have worked (even in synthesis) for years in
my experience.

<snip>

(Followup-to trimmed to comp.ang.vhdl)

Cheers,
Martin

-- 
martin.j.thompson@trw.com 
TRW Conekt - Consultancy in Engineering, Knowledge and Technology
http://www.conekt.net/electronics.html