Re: PR1ME C compiler sources

George Neuner <gneuner2@comcast.net>
Fri, 27 Sep 2019 20:56:58 -0400

          From comp.compilers

Related articles
[3 earlier articles]
Re: PR1ME C compiler sources drb@ihatespam.msu.edu (2019-09-25)
Re: PR1ME C compiler sources drb@ihatespam.msu.edu (2019-09-25)
Re: PR1ME C compiler sources derek@_NOSPAM_knosof.co.uk (Derek M. Jones) (2019-09-26)
Re: PR1ME C compiler sources arnold@skeeve.com (2019-09-26)
Re: PR1ME C compiler sources drb@ihatespam.msu.edu (2019-09-27)
Re: PR1ME C compiler sources derek@_NOSPAM_knosof.co.uk (Derek M. Jones) (2019-09-28)
Re: PR1ME C compiler sources gneuner2@comcast.net (George Neuner) (2019-09-27)
Re: C compiler pointer management on DSPs derek@_NOSPAM_knosof.co.uk (Derek M. Jones) (2019-09-28)
Re: C compiler pointer management on DSPs david.brown@hesbynett.no (David Brown) (2019-09-29)
Re: C compiler pointer management on DSPs 847-115-0292@kylheku.com (Kaz Kylheku) (2019-09-30)
Re: C compiler pointer management on DSPs gneuner2@comcast.net (George Neuner) (2019-10-03)
| List of all articles for this month |

From: George Neuner <gneuner2@comcast.net>
Newsgroups: comp.compilers
Date: Fri, 27 Sep 2019 20:56:58 -0400
Organization: A noiseless patient Spider
References: 19-09-003 19-09-004 19-09-006 19-09-007 19-09-009
Injection-Info: gal.iecc.com; posting-host="news.iecc.com:2001:470:1f07:1126:0:676f:7373:6970"; logging-data="13900"; mail-complaints-to="abuse@iecc.com"
Keywords: C, history, architecture
Posted-Date: 28 Sep 2019 08:40:53 EDT

On Thu, 26 Sep 2019 11:53:20 +0100, "Derek M. Jones"
<derek@_NOSPAM_knosof.co.uk> wrote:


>John,
>
>> [The Prime machines suffered from having too many versions of
>> everything. Page 41 of that quick reference card has a 48 bit pointer
>> format with a bit number in the low 16 bits. It seems unlikely that a
>> C compiler would use that as a general pointer format since it doesn't
>> fit in any sort of normal int, and it's not what you'd want to point
>> at an int or a function or anything bigger than a char. -John]
>
>Some Cray machines and DSP chips have a similar problem with using
>word addressing.
>
>Several solve the problem by defining the word to be the smallest
>addressable unit, making chars 48-bits in the case of some DSPs.


Just curious - what DSPs have 48-bit characters?


I have worked with Analog Devices chips that had 16/32/48 bit words in
internal memory and 32/48 bit words in external memory. Instructions
- and extended floats - were 48 bit, but all other data was either 16
or 32 bit. Due to addressing, an individual character could be a 16 or
32 bit value in internal memory, but had to be a 32-bit value in
external memory. Strings - if you used them - were packed to occupy
as few words as possible, and library string functions (mostly)
expected packed sequences rather than arrays of characters.


George


Post a followup to this message

Return to the comp.compilers page.
Search the comp.compilers archives again.