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Re: Can anyone see a way to improve this ?

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On Mon, 27 Oct 2014, mdj wrote:

> Hi,
>
> Below is a memory test loop for 1 page - assume the high order bytes get replaced for each page being tested. Zero page is deliberately avoided - this runs in either the language card or the $800-$BFFF area of main memory, testing pages of auxiliary memory without assuming any given byte of aux memory works.
>
> The obvious one is to unroll, which I'll do. Just wondering if I'm missing something else obvious.
>
> Thanks,
>
> Matt
>
>
>         LDX   #$00
> NEXTBYTE LDY   #$08
>         LDA   #$01
> NEXTBIT  EOR   #$FF       ; Set and check complement first
>         STA   $2000,X
>         CMP   $2000,X
>         BNE   ERROR
>         EOR   #$FF
>         STA   $2000,X
>         CMP   $2000,X
>         BEQ   CONT
> ERROR    JSR   FLAGERR
> CONT     ASL
>         DEY
>         BNE   NEXTBIT
>         INX
>         BNE   NEXTBYTE
>         RTS
> FLAGERR  RTS              ; Record this meaningfully in the future
>

You might want to change "BEQ COUNT" to "BNE ..." outside of the loop upon 
error, and save a cycle.

And for heavier memory test, you could sacrifice speed, fill the memory 
with pseudo-random pattern, wait some time, and then check with same seed 
again. Rinse and repeat. This does not substitute specialized tests like 
walking 0/1s.

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Thread

Can anyone see a way to improve this ? mdj <mdj.mdj@gmail.com> - 2014-10-27 05:04 -0700
  Re: Can anyone see a way to improve this ? "Anton Treuenfels" <teamtempest@yahoo.com> - 2014-10-27 08:38 -0500
  Re: Can anyone see a way to improve this ? Vladimir Ivanov <none@none.tld> - 2014-10-27 15:56 +0200
    Re: Can anyone see a way to improve this ? Michael J. Mahon <mjmahon@aol.com> - 2014-10-27 13:21 -0500
      Re: Can anyone see a way to improve this ? mdj <mdj.mdj@gmail.com> - 2014-10-27 17:48 -0700
        Re: Can anyone see a way to improve this ? Snertking <SNERTKING@GMAIL.COM> - 2014-10-27 21:28 -0400
          Re: Can anyone see a way to improve this ? mdj <mdj.mdj@gmail.com> - 2014-10-27 22:45 -0700
            Re: Can anyone see a way to improve this ? Michael J. Mahon <mjmahon@aol.com> - 2014-10-29 10:33 -0500
              Re: Can anyone see a way to improve this ? mdj <mdj.mdj@gmail.com> - 2014-10-29 22:54 -0700
                Re: Can anyone see a way to improve this ? qkumba <peter.ferrie@gmail.com> - 2014-10-31 14:46 -0700
      Re: Can anyone see a way to improve this ? Snertking <SNERTKING@GMAIL.COM> - 2014-10-27 21:25 -0400
      Re: Can anyone see a way to improve this ? michael.pohoreski@gmail.com - 2014-12-30 10:12 -0800
  Re: Can anyone see a way to improve this ? awanderin <awanderin@gmail.com> - 2014-10-27 21:35 -0600

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