Re: Forth in VHDL

From	rickman <gnuarm@gmail.com>
Newsgroups	comp.lang.forth
Subject	Re: Forth in VHDL
Date	2016-07-26 13:05 -0400
Organization	A noiseless patient Spider
Message-ID	<nn8584$nu0$1@dont-email.me> (permalink)
References	(5 earlier) <aa10c699-dd41-4a45-b315-a8f10467e3f3@googlegroups.com> <nn5ks2$pj8$1@dont-email.me> <f7479a82-917b-43da-946f-dbb3e22a07fb@googlegroups.com> <nn67bq$tku$1@dont-email.me> <5rGdnckBa-PfhwrKnZ2dnUU78Y3NnZ2d@supernews.com>

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On 7/26/2016 4:07 AM, Andrew Haley wrote:
> rickman <gnuarm@gmail.com> wrote:
>>
>> Yeah, if the CPU runs fast enough that works ok, except for priority
>> issues.  If you have a slow item in the list and a higher priority
>> item needs handling, you also have to get out of the low priority
>> item fast enough to handle the high priority item.  I find this
>> pretty complex in some systems.  But if your needs are simple
>> enough, why use complicated hardware?
>
> I've never found that interrupt priorities woked very well for me.  It
> seems better to do whatever you need to do urgently in the ISR and
> kick a task to do the bulk of the work.  I guess if you're controlling
> something that really needs accurate timing (bit-banging a serial
> port? high-speed stepper motor control?) you might still need
> priorities, but in practice there can only be one high- priority
> interrupt anyway.  ARM has always had FIQ, which is nice.

Priority is a ranking, not just high or low.  The point is that the 
slower interrupts can be interrupted to process a higher priority 
interrupt if that higher priority task is quick enough to not present a 
problem for the lower priority interrupt.  If you have more than two 
such interrupts the issues can get very sticky very quickly, but that is 
not to say it is automatically unmanageable.  Much depends on the details.

-- 

Rick C

Thread

Forth in VHDL rickman <gnuarm@gmail.com> - 2016-07-24 22:29 -0400
  Re: Forth in VHDL rickman <gnuarm@gmail.com> - 2016-07-24 23:01 -0400
    Re: Forth in VHDL rickman <gnuarm@gmail.com> - 2016-07-24 23:05 -0400
      Re: Forth in VHDL Cecil Bayona <cbayona@cbayona.com> - 2016-07-24 22:25 -0500
        Re: Forth in VHDL rickman <gnuarm@gmail.com> - 2016-07-25 00:08 -0400
          Re: Forth in VHDL Cecil Bayona <cbayona@cbayona.com> - 2016-07-24 23:57 -0500
            Re: Forth in VHDL rickman <gnuarm@gmail.com> - 2016-07-25 01:22 -0400
              Re: Forth in VHDL Paul Rubin <no.email@nospam.invalid> - 2016-07-24 22:38 -0700
                Re: Forth in VHDL rickman <gnuarm@gmail.com> - 2016-07-25 01:53 -0400
                Re: Forth in VHDL JUERGEN <epldfpga@aol.com> - 2016-07-25 05:31 -0700
                Re: Forth in VHDL JUERGEN <epldfpga@aol.com> - 2016-07-25 05:36 -0700
                Re: Forth in VHDL Richard Owlett <rowlett@cloud85.net> - 2016-07-25 08:14 -0500
                Re: Forth in VHDL JUERGEN <epldfpga@aol.com> - 2016-07-25 07:37 -0700
                Re: Forth in VHDL JUERGEN <epldfpga@aol.com> - 2016-07-25 08:01 -0700
              Re: Forth in VHDL Cecil Bayona <cbayona@cbayona.com> - 2016-07-25 14:11 -0500
                Re: Forth in VHDL rickman <gnuarm@gmail.com> - 2016-07-25 17:39 -0400
                Re: Forth in VHDL Cecil Bayona <cbayona@cbayona.com> - 2016-07-25 18:01 -0500
                Re: Forth in VHDL rickman <gnuarm@gmail.com> - 2016-07-25 19:40 -0400
                Re: Forth in VHDL Jan Coombs <jenfhaomndgfwutc@murmic.plus.com> - 2016-07-26 11:04 +0100
                Re: Forth in VHDL rickman <gnuarm@gmail.com> - 2016-07-26 11:13 -0400
                Re: Forth in VHDL anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2016-07-26 16:00 +0000
                Re: Forth in VHDL rickman <gnuarm@gmail.com> - 2016-07-26 12:58 -0400
                Re: Forth in VHDL anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2016-07-27 09:39 +0000
                Re: Forth in VHDL rickman <gnuarm@gmail.com> - 2016-07-27 10:01 -0400
                Re: Forth in VHDL Jan Coombs <jenfhaomndgfwutc@murmic.plus.com> - 2016-07-27 22:46 +0100
                Re: Forth in VHDL JUERGEN <epldfpga@aol.com> - 2016-07-26 09:43 -0700
                Re: Forth in VHDL Jan Coombs <jenfhaomndgfwutc@murmic.plus.com> - 2016-07-28 09:12 +0100
                Re: Forth in VHDL rickman <gnuarm@gmail.com> - 2016-07-28 05:04 -0400
                Re: Forth in VHDL JUERGEN <epldfpga@aol.com> - 2016-07-28 07:56 -0700
                Re: Forth in VHDL rickman <gnuarm@gmail.com> - 2016-07-28 13:04 -0400
                Re: Forth in VHDL Jan Coombs <jenfhaomndgfwutc@murmic.plus.com> - 2016-08-02 12:21 +0100
                Re: Forth in VHDL JUERGEN <epldfpga@aol.com> - 2016-07-28 08:02 -0700
    Re: Forth in VHDL rickman <gnuarm@gmail.com> - 2016-07-27 18:15 -0400
      Re: Forth in VHDL Brad Eckert <hwfwguy@gmail.com> - 2016-07-28 15:19 -0700
        Re: Forth in VHDL rickman <gnuarm@gmail.com> - 2016-07-31 18:43 -0400
          Re: Forth in VHDL Paul Rubin <no.email@nospam.invalid> - 2016-07-31 17:10 -0700
  Re: Forth in VHDL Brad Eckert <hwfwguy@gmail.com> - 2016-07-24 20:08 -0700
    Re: Forth in VHDL Brad Eckert <hwfwguy@gmail.com> - 2016-07-24 20:33 -0700
      Re: Forth in VHDL Cecil Bayona <cbayona@cbayona.com> - 2016-07-24 22:58 -0500
        Re: Forth in VHDL rickman <gnuarm@gmail.com> - 2016-07-25 00:17 -0400
          Re: Forth in VHDL Brad Eckert <hwfwguy@gmail.com> - 2016-07-25 10:02 -0700
            Re: Forth in VHDL rickman <gnuarm@gmail.com> - 2016-07-25 14:13 -0400
              Re: Forth in VHDL rickman <gnuarm@gmail.com> - 2016-07-25 14:17 -0400
              Re: Forth in VHDL Brad Eckert <hwfwguy@gmail.com> - 2016-07-25 15:04 -0700
                Re: Forth in VHDL rickman <gnuarm@gmail.com> - 2016-07-25 19:28 -0400
                Re: Forth in VHDL Brad Eckert <hwfwguy@gmail.com> - 2016-07-25 17:20 -0700
                Re: Forth in VHDL rickman <gnuarm@gmail.com> - 2016-07-25 23:07 -0400
                Re: Forth in VHDL Andrew Haley <andrew29@littlepinkcloud.invalid> - 2016-07-26 03:07 -0500
                Re: Forth in VHDL rickman <gnuarm@gmail.com> - 2016-07-26 13:05 -0400
                Re: Forth in VHDL Brad Eckert <hwfwguy@gmail.com> - 2016-07-26 16:22 -0700
                Re: Forth in VHDL Andrew Haley <andrew29@littlepinkcloud.invalid> - 2016-07-27 03:57 -0500
                Re: Forth in VHDL rickman <gnuarm@gmail.com> - 2016-07-27 10:34 -0400
                Re: Forth in VHDL Andrew Haley <andrew29@littlepinkcloud.invalid> - 2016-07-27 11:15 -0500
                Re: Forth in VHDL rickman <gnuarm@gmail.com> - 2016-07-27 12:51 -0400
                Re: Forth in VHDL Andrew Haley <andrew29@littlepinkcloud.invalid> - 2016-07-27 16:12 -0500
                Re: Forth in VHDL "Elizabeth D. Rather" <erather@forth.com> - 2016-07-27 12:43 -1000
                Re: Forth in VHDL rickman <gnuarm@gmail.com> - 2016-07-28 00:40 -0400
                Re: Forth in VHDL hughaguilar96@gmail.com - 2016-08-02 22:45 -0700
                Re: Forth in VHDL rickman <gnuarm@gmail.com> - 2016-07-28 00:39 -0400
  Re: Forth in VHDL wzab01@gmail.com - 2016-07-25 01:48 -0700
  Re: Forth in VHDL JUERGEN <epldfpga@aol.com> - 2016-07-25 05:57 -0700
    Re: Forth in VHDL JUERGEN <epldfpga@aol.com> - 2016-07-25 06:02 -0700
    Re: Forth in VHDL Jan Coombs <jenfhaomndgfwutc@murmic.plus.com> - 2016-07-30 16:40 +0100
      Re: Forth in VHDL JUERGEN <epldfpga@aol.com> - 2016-08-01 08:58 -0700
    Re: Forth in VHDL rickman <gnuarm@gmail.com> - 2016-07-31 17:10 -0400
      Re: Forth in VHDL JUERGEN <epldfpga@aol.com> - 2016-08-01 09:02 -0700
  Re: Forth in VHDL Ilya Tarasov <ilya74.tarasov@gmail.com> - 2016-07-29 05:42 -0700

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