Re: Forth CPUs with NO Interrupts

From	Bernd Paysan <bernd.paysan@gmx.de>
Newsgroups	comp.lang.forth
Subject	Re: Forth CPUs with NO Interrupts
Date	2015-09-02 14:12 +0200
Organization	A noiseless patient Spider
Message-ID	<ms6p0k$f5v$1@dont-email.me> (permalink)
References	(3 earlier) <aF6Fx.7$tS.1@fx07.iad> <c324b35d-cd31-4f70-8841-129b572e2726@googlegroups.com> <k_pFx.19798$Vn5.1113@fx26.iad> <ms5cph$dda$1@dont-email.me> <ms5lks$v7g$1@dont-email.me>

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rickman wrote:
> What can't be done in RAM?  Have you never heard of multiple port RAM?
> Ram is just registers connected to the outside world via multiplexors.

No, RAM is not registers connected to the outside world via multiplexers.  
That's a register file, RAM is way denser, and it's connected to the outside 
world via bit lines and sense amplifiers.

There are two bit lines per bit, inverted to each other.  You can do dual-
ported RAM (by doubling the number of bit lines), but that means you can 
either read two entries in a go, or read one, and write one.  That's what 
most FPGAs have inside; while you theoretically can have more ports (the 
more you have, the less dense is your RAM), you won't see that in an FPGA.

So two reads, one write isn't possible in one cycle on an FPGA.  Just put 
the top of stack into a register, and the number of ports to stack RAM can 
go down to one.

-- 
Bernd Paysan
"If you want it done right, you have to do it yourself"
net2o ID: kQusJzA;7*?t=uy@X}1GWr!+0qqp_Cn176t4(dQ*
http://bernd-paysan.de/

Thread

Forth CPUs with NO Interrupts rickman <gnuarm@gmail.com> - 2015-08-26 00:53 -0400
  Re: Forth CPUs with NO Interrupts anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2015-08-26 08:51 +0000
    Re: Forth CPUs with NO Interrupts rickman <gnuarm@gmail.com> - 2015-08-26 08:50 -0400
    Re: Forth CPUs with NO Interrupts "Elizabeth D. Rather" <erather@forth.com> - 2015-08-26 07:23 -1000
  Re: Forth CPUs with NO Interrupts Mark Wills <markwills1970@gmail.com> - 2015-08-26 04:33 -0700
    Re: Forth CPUs with NO Interrupts rickman <gnuarm@gmail.com> - 2015-08-26 08:46 -0400
    Re: Forth CPUs with NO Interrupts mhx@iae.nl - 2015-08-26 11:17 -0700
    Re: Forth CPUs with NO Interrupts hughaguilar96@gmail.com - 2015-08-26 12:50 -0700
      Re: Forth CPUs with NO Interrupts rickman <gnuarm@gmail.com> - 2015-08-26 18:28 -0400
    Re: Forth CPUs with NO Interrupts hughaguilar96@gmail.com - 2015-08-27 23:44 -0700
      Re: Forth CPUs with NO Interrupts Mux <Yvo.Zoer@gmail.com> - 2015-08-28 18:28 -0700
  Re: Forth CPUs with NO Interrupts Walter Banks <walter@bytecraft.com> - 2015-08-26 11:41 -0400
  Re: Forth CPUs with NO Interrupts Syd Rumpo <usenet@nononono.co.uk> - 2015-08-26 17:12 +0100
    Re: Forth CPUs with NO Interrupts Mux <Yvo.Zoer@gmail.com> - 2015-08-26 09:48 -0700
    Re: Forth CPUs with NO Interrupts rickman <gnuarm@gmail.com> - 2015-08-26 18:39 -0400
  Re: Forth CPUs with NO Interrupts "Ala'a Alawi" <amalawi@gmail.com> - 2015-08-27 08:37 -0700
  Re: Forth CPUs with NO Interrupts pbjtech@gmail.com - 2015-08-30 19:01 -0700
    Re: Forth CPUs with NO Interrupts rickman <gnuarm@gmail.com> - 2015-08-30 22:45 -0400
      Re: Forth CPUs with NO Interrupts Reinhardt Behm <rbehm@hushmail.com> - 2015-08-31 11:09 +0800
    Re: Forth CPUs with NO Interrupts hughaguilar96@gmail.com - 2015-08-30 20:06 -0700
      Re: Forth CPUs with NO Interrupts rickman <gnuarm@gmail.com> - 2015-08-30 23:20 -0400
        Re: Forth CPUs with NO Interrupts hughaguilar96@gmail.com - 2015-09-02 14:14 -0700
          Re: Forth CPUs with NO Interrupts rickman <gnuarm@gmail.com> - 2015-09-02 18:02 -0400
      Re: Forth CPUs with NO Interrupts Bob <bob@none.com> - 2015-08-31 20:49 -0400
        Re: Forth CPUs with NO Interrupts Mark Wills <markwills1970@gmail.com> - 2015-09-01 01:39 -0700
          Re: Forth CPUs with NO Interrupts dunno <dunno@dunno.dunno> - 2015-09-01 17:58 +0000
          Re: Forth CPUs with NO Interrupts Bob <bob@none.com> - 2015-09-01 18:48 -0400
            Re: Forth CPUs with NO Interrupts hughaguilar96@gmail.com - 2015-09-01 16:32 -0700
            Re: Forth CPUs with NO Interrupts Bernd Paysan <bernd.paysan@gmx.de> - 2015-09-02 01:38 +0200
              Re: Forth CPUs with NO Interrupts rickman <gnuarm@gmail.com> - 2015-09-01 22:09 -0400
                Re: Forth CPUs with NO Interrupts Bernd Paysan <bernd.paysan@gmx.de> - 2015-09-02 14:12 +0200
                Re: Forth CPUs with NO Interrupts rickman <gnuarm@gmail.com> - 2015-09-02 12:40 -0400
                Re: Forth CPUs with NO Interrupts Mux <Yvo.Zoer@gmail.com> - 2015-09-02 10:40 -0700
                Re: Forth CPUs with NO Interrupts rickman <gnuarm@gmail.com> - 2015-09-02 16:57 -0400
                Re: Forth CPUs with NO Interrupts Mux <Yvo.Zoer@gmail.com> - 2015-09-02 14:55 -0700
                Re: Forth CPUs with NO Interrupts rickman <gnuarm@gmail.com> - 2015-09-02 18:11 -0400
                Re: Forth CPUs with NO Interrupts Mux <Yvo.Zoer@gmail.com> - 2015-09-02 16:20 -0700
                Re: Forth CPUs with NO Interrupts rickman <gnuarm@gmail.com> - 2015-09-02 20:42 -0400
                Re: Forth CPUs with NO Interrupts Mux <Yvo.Zoer@gmail.com> - 2015-09-02 22:34 -0700
                Re: Forth CPUs with NO Interrupts rickman <gnuarm@gmail.com> - 2015-09-03 12:59 -0400
                Re: Forth CPUs with NO Interrupts Mux <Yvo.Zoer@gmail.com> - 2015-09-03 15:54 -0700
                Re: Forth CPUs with NO Interrupts rickman <gnuarm@gmail.com> - 2015-09-03 19:54 -0400
                Re: Forth CPUs with NO Interrupts Mux <Yvo.Zoer@gmail.com> - 2015-09-03 21:13 -0700
                Re: Forth CPUs with NO Interrupts Jan Coombs <Jan-54 <jenfhaomndgfwutc@murmic.plus.com>> - 2015-09-04 09:48 +0100
                Re: Forth CPUs with NO Interrupts Mux <Yvo.Zoer@gmail.com> - 2015-09-04 08:49 -0700
                Re: Forth CPUs with NO Interrupts hughaguilar96@gmail.com - 2015-09-04 11:15 -0700
                Re: Forth CPUs with NO Interrupts rickman <gnuarm@gmail.com> - 2015-09-04 14:32 -0400
                Re: Forth CPUs with NO Interrupts Mux <Yvo.Zoer@gmail.com> - 2015-09-04 11:36 -0700
                Re: Forth CPUs with NO Interrupts rickman <gnuarm@gmail.com> - 2015-09-04 17:46 -0400
                Re: Forth CPUs with NO Interrupts rickman <gnuarm@gmail.com> - 2015-09-04 11:47 -0400
                Re: Forth CPUs with NO Interrupts Mux <Yvo.Zoer@gmail.com> - 2015-09-04 09:20 -0700
                Re: Forth CPUs with NO Interrupts rickman <gnuarm@gmail.com> - 2015-09-04 12:52 -0400
                Re: Forth CPUs with NO Interrupts Mux <Yvo.Zoer@gmail.com> - 2015-09-04 10:20 -0700
                Re: Forth CPUs with NO Interrupts Bernd Paysan <bernd.paysan@gmx.de> - 2015-09-02 23:35 +0200
                Re: Forth CPUs with NO Interrupts rickman <gnuarm@gmail.com> - 2015-09-02 18:09 -0400
                Re: Forth CPUs with NO Interrupts Bernd Paysan <bernd.paysan@gmx.de> - 2015-09-03 02:07 +0200
                Re: Forth CPUs with NO Interrupts rickman <gnuarm@gmail.com> - 2015-09-02 20:49 -0400
                Re: Forth CPUs with NO Interrupts Bernd Paysan <bernd.paysan@gmx.de> - 2015-09-03 14:30 +0200
    Re: Forth CPUs with NO Interrupts hughaguilar96@gmail.com - 2015-09-02 14:23 -0700

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