Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]

Groups > comp.arch.embedded > #27669

Re: How Physical Memory Mapping / Allocation works

Show all headers | View raw

On 27/02/18 11:34, Ilias Abrams wrote:
> Τη Τρίτη, 27 Φεβρουαρίου 2018 - 7:51:33 π.μ. UTC, ο χρήστης David Brown έγραψε:
>>
>> What sort of systems are you talking about here?  Very roughly, you can
>> divide processors into two categories.
>>
> 
>>
>> And there are "small" ones designed for running a single program, either
>> "bare metal" or with a small "real-time operating system", with all the
>> code compiled and linked at one time.  Then the logical addresses and
>> physical addresses are the same, and you often don't have any kind of
>> memory protection at all.
>>
>>
> Thanks David, I would like to focus on this more. The 1GB memory that
> I said is only for example. Can you please give more details?
> Microcontrollers work on that way? Basically I want to write a
> program with no OS. Only my software run on the hardware and have 1-1
> mapping meaning my physical address space translated to logical
> addresses. I dont know so much yet about programming but I think that
> C make use of the logical addresses and not the physical but with 1-1
> mapping maybe can achieve this.
> 

You are not making much sense here.  It is like saying you'd like to go
on a car holiday, and would prefer a manual gear car to an automatic.
No one could give you advice because they don't know where you want to
go, what you want to do, if you want to buy a care or hire it, or
anything else.

Or it is like going to an author's conference and saying "I'd like to
write a book.  Perhaps it will be hardback, but that's just an example.
 Do the numbers on the bottom of the pages match the physical sheets of
paper in book printing?"

Saying "I want to write a program" is equally vague.  We have no idea if
you are trying to program on a PC, or have bought a microcontroller
based embedded card, or even if you have a target at all.  We have no
idea what your program would be doing, or what you know or don't know
about the matter.

We don't know if you are a student trying to get help with some
homework, a professional who has been given a task way outside your
experience, or a hobby developer just trying to learn something new.

You have to take a step back and think about what you know, and where
you want to go, and try to give a better description of it.  And be
ready for when the advice you get is "don't start with C" or "don't
worry about physical memory mappings - you'll get there in a couple of
years".

Back to comp.arch.embedded | Previous | Next — Previous in thread | Next in thread | Find similar | Unroll thread

Thread

How Physical Memory Mapping / Allocation works Ilias Abrams <iliasabrams@gmail.com> - 2018-02-26 14:07 -0800
  Re: How Physical Memory Mapping / Allocation works Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> - 2018-02-26 21:26 -0500
  Re: How Physical Memory Mapping / Allocation works David Brown <david.brown@hesbynett.no> - 2018-02-27 08:51 +0100
    Re: How Physical Memory Mapping / Allocation works Ilias Abrams <iliasabrams@gmail.com> - 2018-02-27 02:34 -0800
      Re: How Physical Memory Mapping / Allocation works David Brown <david.brown@hesbynett.no> - 2018-02-27 14:34 +0100
        Re: How Physical Memory Mapping / Allocation works Ilias Abrams <iliasabrams@gmail.com> - 2018-02-27 10:11 -0800
          Re: How Physical Memory Mapping / Allocation works Jack <jack4747@gmail.com> - 2018-02-27 23:31 -0800
            Re: How Physical Memory Mapping / Allocation works David Brown <david.brown@hesbynett.no> - 2018-02-28 09:51 +0100
              Re: How Physical Memory Mapping / Allocation works Paul <paul@pcserviceselectronics.co.uk> - 2018-03-01 14:54 +0000
          Re: How Physical Memory Mapping / Allocation works Gunther Mannigel <newsgroups@mannigel.net> - 2018-03-03 22:54 +0100
    Re: How Physical Memory Mapping / Allocation works Ilias Abrams <iliasabrams@gmail.com> - 2018-02-27 02:36 -0800
      Re: How Physical Memory Mapping / Allocation works Mel Wilson <mwilson@the-wire.com> - 2018-02-27 16:51 +0000
      Re: How Physical Memory Mapping / Allocation works antispam@math.uni.wroc.pl - 2018-03-10 14:05 +0000
  Re: How Physical Memory Mapping / Allocation works Tauno Voipio <tauno.voipio@notused.fi.invalid> - 2018-02-27 10:14 +0200

csiph-web