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Re: things i would ban from clc

From Don Y <this@isnotme.com>
Newsgroups comp.lang.c
Subject Re: things i would ban from clc
Date 2012-03-14 12:09 -0700
Organization Aioe.org NNTP Server
Message-ID <jjqqcd$85c$1@speranza.aioe.org> (permalink)
References <jjjb49$gdr$1@reader1.panix.com> <18112893.6499.1331628747910.JavaMail.geo-discussion-forums@ynjc20> <4f5f2102$0$1388$4fafbaef@reader2.news.tin.it> <5960235.1401.1331713091592.JavaMail.geo-discussion-forums@vbhz5>

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Hi Nick,

On 3/14/2012 1:18 AM, nick_keighley_nospam@hotmail.com wrote:
> On Tuesday, March 13, 2012 10:31:42 AM UTC, io_x wrote:
>> <nick_keighley_nospam@hotmail.com>  ha scritto nel messaggio
>> news:18112893.6499.1331628747910.JavaMail.geo-discussion-forums@ynjc20...
>>> On Sunday, March 11, 2012 11:05:45 PM UTC, Joe keane wrote:
>
>>> ... or DSPs having 32 bit chars?
>>
>> Do dsp having 32 bit chars, use 4 times memory for represent
>> the same 0..255 ascii .txt?
>
> you'd have to ask someone who's used such a device; but yes i
> believe so. Everything's 32 bits. Note DSPs typically don't do
> a lot of string processing.

Of course, you can *pack* smaller data into those "words"
but extracting them isn't as simple as saying "foo[i]".

I designed a processor many years ago with 16b memory.
When we ran our first test program on the hardware,
*nothing* worked.  This was devastating.  I was 102% sure
the microcode in my processor was correct/working (I had
debugged it at DC).  And, my faith in the guy who wrote
the code was unquestionable!

We eventually realized that I had designed the instruction
set assuming all addresses were for "16b data".  I.e.,
there were no "bytes" in memory.  The guy who wrote the
software assumed the more typical interpretation of
"byte addressable" memory.  When we eventually realized
this ("Um, didn't you notice that all of your addresses
had a '0' in their rightmost bit?  Knowing *me*, do you
think I would have wasted that bit in the instruction
format??") it was a trivial change to the code generator
to ensure the addresses in the code matched the addresses
that the instruction decoder expected!  :-/

"Colossal mistakes that almost were!"

>> what about assembly program instructions?
>
> not a clue. Maybe code is different from data. But I'm guessing wildly.

Different DSP's have different capabilities and, thus, different
data types that they can support.  E.g., some are geared towards
floating point operations while most stick to the integer realm.

>> their program take more space in memory?
>>
>> i not see any other danger on that but only conversions must
>> be ok for comunicate other computers...
>
> C places no requirements on implementions that they must be capable
> of communicating with other computers. But yes, producing strings
> of bytes must be a bit of a pain.

The zero-th order summary of a DSP is:  MAC as fast as possible
(Multiply and ACcumulate).  If you look at the die, you see
that a disproportionate amount of it is dedicated to crunching
numbers (instead of managing memory, decoding instructions, etc.)

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Thread

things i would ban from clc jgk@panix.com (Joe keane) - 2012-03-11 23:05 +0000
  Re: things i would ban from clc Keith Thompson <kst-u@mib.org> - 2012-03-12 10:33 -0700
    Re: things i would ban from clc gazelle@shell.xmission.com (Kenny McCormack) - 2012-03-12 23:57 +0000
  Re: things i would ban from clc jacob navia <jacob@spamsink.net> - 2012-03-12 18:44 +0100
    Re: things i would ban from clc Don Y <this@isnotme.com> - 2012-03-12 12:26 -0700
      Re: things i would ban from clc "osmium" <r124c4u102@comcast.net> - 2012-03-12 14:36 -0600
        Re: things i would ban from clc Don Y <this@isnotme.com> - 2012-03-12 13:57 -0700
      Re: things i would ban from clc James Kuyper <jameskuyper@verizon.net> - 2012-03-12 17:34 -0400
        Re: things i would ban from clc Don Y <this@isnotme.com> - 2012-03-12 15:00 -0700
          Re: things i would ban from clc James Kuyper <jameskuyper@verizon.net> - 2012-03-12 18:21 -0400
            Re: things i would ban from clc Don Y <this@isnotme.com> - 2012-03-12 15:43 -0700
              Re: things i would ban from clc jacob navia <jacob@spamsink.net> - 2012-03-12 23:53 +0100
                Re: things i would ban from clc Don Y <this@isnotme.com> - 2012-03-12 17:17 -0700
                Re: things i would ban from clc jacob navia <jacob@spamsink.net> - 2012-03-13 09:09 +0100
                Re: things i would ban from clc Don Y <this@isnotme.com> - 2012-03-13 01:24 -0700
                Re: things i would ban from clc Keith Thompson <kst-u@mib.org> - 2012-03-13 05:59 -0700
                Re: things i would ban from clc Don Y <this@isnotme.com> - 2012-03-13 10:55 -0700
                Re: things i would ban from clc blp@cs.stanford.edu (Ben Pfaff) - 2012-03-13 11:07 -0700
                Re: things i would ban from clc Don Y <this@isnotme.com> - 2012-03-13 11:25 -0700
                Re: things i would ban from clc blp@cs.stanford.edu (Ben Pfaff) - 2012-03-13 11:32 -0700
                Re: things i would ban from clc Keith Thompson <kst-u@mib.org> - 2012-03-13 12:18 -0700
                Re: things i would ban from clc Don Y <this@isnotme.com> - 2012-03-13 16:13 -0700
                Re: things i would ban from clc Don Y <this@isnotme.com> - 2012-03-13 13:49 -0700
                Re: things i would ban from clc James Kuyper <jameskuyper@verizon.net> - 2012-03-13 17:14 -0400
                Re: things i would ban from clc Don Y <this@isnotme.com> - 2012-03-13 14:35 -0700
                Re: things i would ban from clc James Kuyper <jameskuyper@verizon.net> - 2012-03-13 18:09 -0400
                Re: things i would ban from clc Don Y <this@isnotme.com> - 2012-03-13 16:06 -0700
                Re: things i would ban from clc "io_x" <a@b.c.invalid> - 2012-03-14 08:18 +0100
                Re: things i would ban from clc "io_x" <a@b.c.invalid> - 2012-03-14 10:07 +0100
                Re: things i would ban from clc Don Y <this@isnotme.com> - 2012-03-14 12:41 -0700
                Re: things i would ban from clc "io_x" <a@b.c.invalid> - 2012-03-14 21:53 +0100
                Re: things i would ban from clc Don Y <this@isnotme.com> - 2012-03-15 14:16 -0700
                Re: things i would ban from clc "io_x" <a@b.c.invalid> - 2012-03-18 07:14 +0100
                Re: things i would ban from clc Jens Gustedt <jens.gustedt@loria.fr> - 2012-03-14 10:39 +0100
                Re: things i would ban from clc Ben Pfaff <blp@cs.stanford.edu> - 2012-03-13 14:33 -0700
                Re: things i would ban from clc Don Y <this@isnotme.com> - 2012-03-13 14:40 -0700
                Re: things i would ban from clc Tim Rentsch <txr@alumni.caltech.edu> - 2012-03-13 16:25 -0700
                Re: things i would ban from clc Don Y <this@isnotme.com> - 2012-03-14 00:51 -0700
                Re: things i would ban from clc Tim Rentsch <txr@alumni.caltech.edu> - 2012-03-14 14:25 -0700
                Re: things i would ban from clc Don Y <this@isnotme.com> - 2012-03-15 13:40 -0700
                Re: things i would ban from clc Tim Rentsch <txr@alumni.caltech.edu> - 2012-03-18 17:05 -0700
                Re: things i would ban from clc Don Y <this@isnotme.com> - 2012-03-23 11:59 -0700
                Re: things i would ban from clc Robert Wessel <robertwessel2@yahoo.com> - 2012-03-23 17:02 -0500
                Re: things i would ban from clc Don Y <this@isnotme.com> - 2012-03-23 16:51 -0700
                Re: things i would ban from clc "io_x" <a@b.c.invalid> - 2012-03-24 07:16 +0100
                Re: things i would ban from clc Tim Rentsch <txr@alumni.caltech.edu> - 2012-03-27 11:26 -0700
                Re: things i would ban from clc Kaz Kylheku <kaz@kylheku.com> - 2012-03-23 19:43 +0000
                Re: things i would ban from clc Rui Maciel <rui.maciel@gmail.com> - 2012-03-23 19:45 +0000
                Re: things i would ban from clc Jens Gustedt <jens.gustedt@loria.fr> - 2012-03-23 23:49 +0100
                Re: things i would ban from clc Ian Collins <ian-news@hotmail.com> - 2012-03-24 11:54 +1300
                Re: things i would ban from clc Jens Gustedt <jens.gustedt@loria.fr> - 2012-03-24 09:26 +0100
                Re: things i would ban from clc gwowen <gwowen@gmail.com> - 2012-03-26 07:31 -0700
                Re: things i would ban from clc Kaz Kylheku <kaz@kylheku.com> - 2012-03-24 05:45 +0000
                Re: things i would ban from clc Jens Gustedt <jens.gustedt@loria.fr> - 2012-03-24 09:31 +0100
                Re: things i would ban from clc James Kuyper <jameskuyper@verizon.net> - 2012-03-13 14:34 -0400
                Re: things i would ban from clc Tim Rentsch <txr@alumni.caltech.edu> - 2012-03-13 16:18 -0700
                Re: things i would ban from clc "io_x" <a@b.c.invalid> - 2012-03-14 08:18 +0100
                Re: things i would ban from clc Tim Rentsch <txr@alumni.caltech.edu> - 2012-03-14 14:06 -0700
                Re: things i would ban from clc Jorgen Grahn <grahn+nntp@snipabacken.se> - 2012-03-15 15:22 +0000
                Re: things i would ban from clc Don Y <this@isnotme.com> - 2012-03-15 12:26 -0700
                Re: things i would ban from clc jacob navia <jacob@spamsink.net> - 2012-03-15 21:28 +0100
                Re: things i would ban from clc Don Y <this@isnotme.com> - 2012-03-15 13:49 -0700
                Re: things i would ban from clc Ben Bacarisse <ben.usenet@bsb.me.uk> - 2012-03-15 16:36 +0000
                Re: things i would ban from clc Don Y <this@isnotme.com> - 2012-03-15 12:16 -0700
                Re: things i would ban from clc Ben Bacarisse <ben.usenet@bsb.me.uk> - 2012-03-16 00:13 +0000
                Re: things i would ban from clc Don Y <this@isnotme.com> - 2012-03-15 20:40 -0700
                Re: things i would ban from clc gwowen <gwowen@gmail.com> - 2012-03-13 01:52 -0700
                Re: things i would ban from clc "io_x" <a@b.c.invalid> - 2012-03-13 11:31 +0100
                Re: things i would ban from clc jacob navia <jacob@spamsink.net> - 2012-03-13 11:41 +0100
                Re: things i would ban from clc gwowen <gwowen@gmail.com> - 2012-03-13 06:06 -0700
                Re: things i would ban from clc jacob navia <jacob@spamsink.net> - 2012-03-13 15:06 +0100
                Re: things i would ban from clc ImpalerCore <jadill33@gmail.com> - 2012-03-13 07:46 -0700
                Re: things i would ban from clc jacob navia <jacob@spamsink.net> - 2012-03-13 19:08 +0100
                Re: things i would ban from clc Ben Bacarisse <ben.usenet@bsb.me.uk> - 2012-03-13 13:20 +0000
                Re: things i would ban from clc Jens Gustedt <jens.gustedt@loria.fr> - 2012-03-13 20:41 +0100
                Re: things i would ban from clc Kaz Kylheku <kaz@kylheku.com> - 2012-03-13 19:34 +0000
                Re: things i would ban from clc Don Y <this@isnotme.com> - 2012-03-13 16:14 -0700
                Re: things i would ban from clc Kaz Kylheku <kaz@kylheku.com> - 2012-03-13 23:28 +0000
                Re: things i would ban from clc Don Y <this@isnotme.com> - 2012-03-13 21:18 -0700
      Re: things i would ban from clc Ian Collins <ian-news@hotmail.com> - 2012-03-13 20:19 +1300
        Re: things i would ban from clc Don Y <this@isnotme.com> - 2012-03-13 01:09 -0700
          Re: things i would ban from clc Ian Collins <ian-news@hotmail.com> - 2012-03-13 21:32 +1300
  Re: things i would ban from clc nick_keighley_nospam@hotmail.com - 2012-03-13 01:52 -0700
    Re: things i would ban from clc "io_x" <a@b.c.invalid> - 2012-03-13 11:31 +0100
      Re: things i would ban from clc nick_keighley_nospam@hotmail.com - 2012-03-14 01:18 -0700
        Re: things i would ban from clc Don Y <this@isnotme.com> - 2012-03-14 12:09 -0700
  Re: things i would ban from clc ArifulHossain tuhin <etothepowerpi@gmail.com> - 2012-03-14 13:01 -0700

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