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Re: OT (slightly) What is the "best" processor for a new project?

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rickman wrote:

> On 6/17/2013 7:15 PM, Hugh Aguilar wrote:
>> Aren't FPGAs generally always more expensive and power-hungry than
>> PLDs? On the plus side, they are really big and it is possible to fit
>> big processors in them.
> 
> I'd be willing to bet the MinForth CPU is actually much slower than the
> B16 or even my poor little CPU.  No, it won't fit on an isp1048 PLD, but
> then the MinForth didn't either.  It used external memory, no?  The B16
> and my designs will run entirely on an FPGA without external memory.  If
> the 1048 in isp1048 indicates the number of LUTs or macrocells, then my
> design would fit the isp1048 other than the memory used.  In fact, it
> only uses 600 LUTs the last time I built it.

Your's is about as big as the b16, and from the data sheet, I get the 
impression that the b16 would fit.  Though I never tried, because that is 
not an interesting target.  The b16 wasn't deliberately designed for FPGAs, 
though of course, hobbyists won't make "real silicon", and as a professional 
IC designer, I used FPGAs as test vehicle.  The whole FPGA stuff is just a 
red herring: If you go to serious mass production, you go to full custom 
ICs, doing whatever you need all on one single die.  If you don't go to mass 
production, it's a failed project or a hobby, or the controller is just a 
small part of the entire project, and it's development costs that matter, 
not production costs.  Then you most likely go with an off-the-shelf CPU, 
unless you want to have replacement parts for 30 years, in which case using 
FPGAs is a better idea (you won't have the same FPGAs in 30 years, but you 
will be able to create a replacement on board level).

> I didn't try to make my CPU design fit an isp1048 because I have no
> reason to use obsolete technology.  When I can get a 1280 LUT FPGA with
> 8 kB of RAM for under $4 that draws microAmps of current, why would I
> use something like an isp1048?

Indeed.  But Hugh told us that 8kB of RAM are not enough, and that you need 
thousands of primitives (of which most of them are never used...), *and* you 
need to uber-optimize for threading... m(

Hugh should actually check the numbers.  Call/return pairs are not happening 
that often, even in my well-factored b16 programs.  Even the high-level 
words are a mix of primitives and calls.  I would probably gain a few 
percent of speed with a parallel return, but then, every instruction would 
have one bit more, which means more instruction fetch cycles.  This isn't a 
zero-sum game.  And quite often, the tail call optimization takes out that 
cycle without that cost.

-- 
Bernd Paysan
"If you want it done right, you have to do it yourself"
http://bernd-paysan.de/

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Re: OT (slightly) What is the "best" processor for a new project? Hugh Aguilar <hughaguilar96@yahoo.com> - 2013-06-16 23:17 -0700
  Re: OT (slightly) What is the "best" processor for a new project? Bernd Paysan <bernd.paysan@gmx.de> - 2013-06-17 14:19 +0200
    Re: OT (slightly) What is the "best" processor for a new project? Hugh Aguilar <hughaguilar96@yahoo.com> - 2013-06-17 16:04 -0700
    Re: OT (slightly) What is the "best" processor for a new project? Hugh Aguilar <hughaguilar96@yahoo.com> - 2013-06-17 16:15 -0700
      Re: OT (slightly) What is the "best" processor for a new project? rickman <gnuarm@gmail.com> - 2013-06-18 00:01 -0400
        Re: OT (slightly) What is the "best" processor for a new project? Bernd Paysan <bernd.paysan@gmx.de> - 2013-06-19 15:33 +0200
          Re: OT (slightly) What is the "best" processor for a new project? rickman <gnuarm@gmail.com> - 2013-06-19 17:25 -0400
            Re: OT (slightly) What is the "best" processor for a new project? Hugh Aguilar <hughaguilar96@yahoo.com> - 2013-06-19 17:00 -0700
              Re: OT (slightly) What is the "best" processor for a new project? rickman <gnuarm@gmail.com> - 2013-06-20 18:35 -0400
          Re: OT (slightly) What is the "best" processor for a new project? Hugh Aguilar <hughaguilar96@yahoo.com> - 2013-06-19 17:38 -0700
            Re: OT (slightly) What is the "best" processor for a new project? Bernd Paysan <bernd.paysan@gmx.de> - 2013-06-20 12:51 +0200
              Re: OT (slightly) What is the "best" processor for a new project? anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2013-06-20 15:28 +0000
              Re: OT (slightly) What is the "best" processor for a new project? hughaguilar96@yahoo.com - 2013-06-20 18:39 -0700
                Re: OT (slightly) What is the "best" processor for a new project? Bernd Paysan <bernd.paysan@gmx.de> - 2013-06-21 14:50 +0200
                Re: OT (slightly) What is the "best" processor for a new project? hughaguilar96@yahoo.com - 2013-06-22 18:56 -0700
                Re: OT (slightly) What is the "best" processor for a new project? "WJ" <w_a_x_man@yahoo.com> - 2013-06-23 02:35 +0000
                Re: OT (slightly) What is the "best" processor for a new project? hughaguilar96@yahoo.com - 2013-06-22 20:48 -0700
                Re: OT (slightly) What is the "best" processor for a new project? Bernd Paysan <bernd.paysan@gmx.de> - 2013-06-23 14:49 +0200
                Re: OT (slightly) What is the "best" processor for a new project? hughaguilar96@yahoo.com - 2013-06-26 18:08 -0700
                Re: OT (slightly) What is the "best" processor for a new project? Bernd Paysan <bernd.paysan@gmx.de> - 2013-06-27 16:32 +0200
                Re: OT (slightly) What is the "best" processor for a new project? hughaguilar96@yahoo.com - 2013-06-30 10:10 -0700
                Re: OT (slightly) What is the "best" processor for a new project? rickman <gnuarm@gmail.com> - 2013-06-30 15:18 -0400
                Re: OT (slightly) What is the "best" processor for a new project? hughaguilar96@yahoo.com - 2013-06-30 16:01 -0700
                Re: OT (slightly) What is the "best" processor for a new project? rickman <gnuarm@gmail.com> - 2013-06-30 20:22 -0400
                Re: OT (slightly) What is the "best" processor for a new project? Bernd Paysan <bernd.paysan@gmx.de> - 2013-06-30 21:22 +0200
                Re: OT (slightly) What is the "best" processor for a new project? hughaguilar96@yahoo.com - 2013-06-30 15:52 -0700
                Re: OT (slightly) What is the "best" processor for a new project? Bernd Paysan <bernd.paysan@gmx.de> - 2013-07-01 02:02 +0200
                Re: OT (slightly) What is the "best" processor for a new project? hughaguilar96@yahoo.com - 2013-06-30 19:25 -0700
                Re: OT (slightly) What is the "best" processor for a new project? Andrew Haley <andrew29@littlepinkcloud.invalid> - 2013-07-01 02:34 -0500
                Re: OT (slightly) What is the "best" processor for a new project? rickman <gnuarm@gmail.com> - 2013-07-01 16:26 -0400
                Re: OT (slightly) What is the "best" processor for a new project? Bernd Paysan <bernd.paysan@gmx.de> - 2013-07-01 23:08 +0200
                Re: OT (slightly) What is the "best" processor for a new project? rickman <gnuarm@gmail.com> - 2013-07-01 18:10 -0400
                Re: OT (slightly) What is the "best" processor for a new project? "Elizabeth D. Rather" <erather@forth.com> - 2013-07-01 12:35 -1000
                Re: OT (slightly) What is the "best" processor for a new project? rickman <gnuarm@gmail.com> - 2013-07-01 18:42 -0400
                Re: OT (slightly) What is the "best" processor for a new project? "Elizabeth D. Rather" <erather@forth.com> - 2013-07-01 13:03 -1000
                Re: OT (slightly) What is the "best" processor for a new project? anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2013-07-02 07:20 +0000
                Re: OT (slightly) What is the "best" processor for a new project? "Elizabeth D. Rather" <erather@forth.com> - 2013-07-02 07:38 -1000
                Re: OT (slightly) What is the "best" processor for a new project? anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2013-07-02 07:24 +0000
                Re: OT (slightly) What is the "best" processor for a new project? Bernd Paysan <bernd.paysan@gmx.de> - 2013-07-02 13:02 +0200
                Re: OT (slightly) What is the "best" processor for a new project? "Rod Pemberton" <do_not_have@notemailnotq.cpm> - 2013-07-02 05:58 -0400
                Re: OT (slightly) What is the "best" processor for a new project? Andrew Haley <andrew29@littlepinkcloud.invalid> - 2013-07-02 03:34 -0500
                Re: OT (slightly) What is the "best" processor for a new project? hughaguilar96@yahoo.com - 2013-07-01 20:01 -0700
                Re: OT (slightly) What is the "best" processor for a new project? "WJ" <w_a_x_man@yahoo.com> - 2013-07-02 04:43 +0000
                Re: OT (slightly) What is the "best" processor for a new project? Andrew Haley <andrew29@littlepinkcloud.invalid> - 2013-07-02 03:41 -0500
                Re: OT (slightly) What is the "best" processor for a new project? "Rod Pemberton" <do_not_have@notemailnotq.cpm> - 2013-07-02 06:09 -0400
                Re: OT (slightly) What is the "best" processor for a new project? hughaguilar96@yahoo.com - 2013-07-02 13:51 -0700
                Re: OT (slightly) What is the "best" processor for a new project? daveyrotten <danw8804@gmail.com> - 2013-07-02 14:37 -0700
                Re: OT (slightly) What is the "best" processor for a new project? daveyrotten <danw8804@gmail.com> - 2013-07-02 14:56 -0700
                Re: OT (slightly) What is the "best" processor for a new project? Bernd Paysan <bernd.paysan@gmx.de> - 2013-07-03 00:30 +0200
                Re: OT (slightly) What is the "best" processor for a new project? Andrew Haley <andrew29@littlepinkcloud.invalid> - 2013-07-03 02:19 -0500
                Re: OT (slightly) What is the "best" processor for a new project? "Rod Pemberton" <do_not_have@notemailnotq.cpm> - 2013-07-03 05:18 -0400
                Re: OT (slightly) What is the "best" processor for a new project? hughaguilar96@yahoo.com - 2013-07-03 18:10 -0700
                Re: OT (slightly) What is the "best" processor for a new project? "Rod Pemberton" <do_not_have@notemailnotq.cpm> - 2013-07-03 05:30 -0400
                Static superinstructions(was: OT (slightly) What is the "best" ...) anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2013-07-03 14:33 +0000
                Re: Static superinstructions(was: OT (slightly) What is the "best" ...) Bernd Paysan <bernd.paysan@gmx.de> - 2013-07-04 00:41 +0200
                Re: Static superinstructions(was: OT (slightly) What is the "best" ...) "Rod Pemberton" <do_not_have@notemailnotq.cpm> - 2013-07-07 11:32 -0400
                Re: OT (slightly) What is the "best" processor for a new project? hughaguilar96@yahoo.com - 2013-07-03 18:31 -0700
                Re: OT (slightly) What is the "best" processor for a new project? "Rod Pemberton" <do_not_have@notemailnotq.cpm> - 2013-07-07 11:28 -0400
                Re: OT (slightly) What is the "best" processor for a new project? rickman <gnuarm@gmail.com> - 2013-07-02 16:44 -0400
                Re: OT (slightly) What is the "best" processor for a new project? "Rod Pemberton" <do_not_have@notemailnotq.cpm> - 2013-07-02 05:56 -0400
                Re: OT (slightly) What is the "best" processor for a new project? Andrew Haley <andrew29@littlepinkcloud.invalid> - 2013-07-02 05:58 -0500
                Re: OT (slightly) What is the "best" processor for a new project? "Rod Pemberton" <do_not_have@notemailnotq.cpm> - 2013-07-03 05:57 -0400
                Re: OT (slightly) What is the "best" processor for a new project? Andrew Haley <andrew29@littlepinkcloud.invalid> - 2013-07-03 06:43 -0500
                Re: OT (slightly) What is the "best" processor for a new project? rickman <gnuarm@gmail.com> - 2013-06-30 20:29 -0400
                Re: OT (slightly) What is the "best" processor for a new project? rickman <gnuarm@gmail.com> - 2013-06-27 10:58 -0400

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