DOS ain't dead

Using Dos for Real Time applications -> CLI (Developers)

posted by Damien, 02.01.2013, 13:20

>
> Hehe, this is because old bios writers was the masters of assembler and did
> theirs work well. Now nobody cares and the most important think is profit
> and short time to market so why to bother with some optimizations, customer
> fuck you...
> You can modify interrupt vector table such way you hook an interrupt vector
> to your dummy routine containing only IRET - this is fast as possible. You
> can walk vector by vector and check when the 400us delay disapper. First
> try timer interrupt.

Hello,

I have made some tests on several computers and it seems that I get as many behaviours as the number of PC I test.

In my test program I just added asm("CLI") at the beginning and asm("STI") at the end (programming in C with djgpp), to see the influence of masquable interrupts.
(It may be brutal, I don't know much about this).

Here is what I get:

On config A (AMD 2800+):
without CLI, I observe some 400us task, once a second.
with CLI : program ends early(strange), some smaller tasks disapper, but still 400us task
=> so this strange 400us task is not a masquable interrupt?

On config B (Intel Celeron800)
without CLI, I observe some 40us task
with CLI : all the loops last the same time, 8usec
=> on this config there is no strange task, all the 30-40us tasks were due to some masquable interrupts

On config C (Inter P4 3.2Ghz)
without CLI, I observe some 270us task.
with CLI :some smaller tasks disapper, but still 270us task
=> so this strange 270us task is not due to masquable interrupt...


So, in your opinion, if I can't avoid these tasks (270 or 400us) with CLI, what can it be ? Do you have any other ideas of how to change it?

THanks

Complete thread:

• Using Dos for Real Time applications - Damien, 23.12.2012, 18:41 (Developers)
  • Using Dos for Real Time applications -> CLI - DOS386, 24.12.2012, 09:39
    • Using Dos for Real Time applications -> CLI - RayeR, 24.12.2012, 15:13
      • Using Dos for Real Time applications -> CLI - Damien, 26.12.2012, 12:50
      • Using Dos for Real Time applications -> CLI - Damien, 27.12.2012, 23:23
        • Using Dos for Real Time applications -> CLI - RayeR, 28.12.2012, 01:32
          • Using Dos for Real Time applications -> CLI - Damien, 02.01.2013, 13:20
            • Using Dos for Real Time applications -> CLI - Laaca, 02.01.2013, 21:02
              • Using Dos for Real Time applications -> CLI - RayeR, 02.01.2013, 23:22
              • Using Dos for Real Time applications -> CLI - Damien, 05.01.2013, 14:10
                • Using Dos for Real Time applications -> CLI - RayeR, 06.01.2013, 21:43
                  • Using Dos for Real Time applications -> CLI - Damien, 09.01.2013, 13:12
                    • Using Dos for Real Time applications -> CLI - RayeR, 09.01.2013, 13:52
                      • Using Dos for Real Time applications -> CLI - Arjay, 09.01.2013, 23:40