Re: Byte to byte compare, duplicate file finder/killer


Wannabee wrote:

Your last recent mails can't be quoted ?
did you change your news-tool ?
Ok, I quote it manually yet.

An often seen confusion: Relative branch(call and jump)operands are
addded to he address 'after' the call/jmp, and any overflow on this
ADD will just be truncated, so it looks and act as if they all were
signed, but only byte operands become sign-extended to 16/32/64 bit.
The CPU don't know 'signed' addressing at all.

? I dont understand.

The CPU don't know at all a signed ADD.
ie:
0040_00fe
0040_0100: 72 FC only the 'FC'-byte becomes sign-extended
0040_0102: but then added 'unsigned':

0040_0102
ffff_fffc
---------
1_0040_00fe

the overflow will be just ignored and truncated ...
this is the 'tricky signed' operation which may confuse HLL folks.

The short form, is using signed numbers

Yes, byte forms become sign-extended,
the same is valid for other short forms:

83 .. imm8
6B .. imm8

L0:
xor eax eax
jb L0<

this become:
33 C0
72 FC

I would have guessed it should be 72 FE (-2) bytes
but it looks ok, if we count from the end of the instruction.
FC (-4), and this hold for -6, -8, -12 as well, and for jmp L0< as well.

The long form:

L0:
xor eax eax
jb L0<<

33 C0
0F 82 F8 FF FF FF (-8)

L0:
xor eax eax
jmp L0<<

33 C0
E9 F9 FF FF FF (-7)

Looks ok to me ... ?
Anything I dont see here?

That's all about it. And you dont need to calculate the offset as signed.
Just ADD the RELATIVE-value to NEXTadress, truncate and see the target.

btw, thanks for helping me with this. It is real beauty counting bytes
in the hex form.

Always welcome, we dont need our fingers nor books to count bytes :)


But I just lost a whole hardrive for some reason.
It was my INFO drive. Where I store all my assemblers, and downloaded
code, all PDFs for intel amd and all the things that matters most to me.
Including all of my source code!

Who was it ???? :))

Not me this time :)
Good you remind me for making new backup-CDs for my info-book right
now. I once had the same experience ...
But it was at least a chance to resort, reorder and cleanup all
the stuff collected over the years.

Heh. I have the same problem. If I had enough hardrive space, I likly
download the entire internet.

Yeah, unfortunately internet pages are prone to change quite often,
so some of the good old things are gone forever.


HEX cannot die until our CPUs understand anything else then binary.

Then it will need to understand also mockery.
We will taunt the thing, and it will revenge itself by playing the
startup sounds for windows NT over and over...

:)
Be aware..., we'v got already voice controlled devices,
but by luck they aren't too smart anyway.

Yes I read Phils signature :D
What will likly do us in, is that in order to be dangerous, they do not
need to be smart.....
If computer was smart, this was the last thing to fear. What I fear is a
stupid computer, and you do not need a smart one for just aim, verify and
fire.

Anyway, we may soon have 8 meters of water ovr our heads, so.....

One meter sea level increase will already be enough to shrink
human population to a more healty size.
This planet can only hold about 1 GigaMen parasites, sure not 8.
So if there aren't enough wars, pests or disasters then mother
Nature will adjust the environment to regain balance.


I'd have 33"DB" for CLEAR ebx ;) I always use '31'DB but don't care.
yes. Theres at least those 3 doing exactly the same.
I see only two equals,the third:
33 eb xor epb,ebx
31 eb xor ebx,epb
A tiny sticker on my PC helps me in case I'm tired:

|7|6|5|4|3|2|1|0|
|mod| ttt | rm |

That surprice me. I am guessing the reason is that you design,
and then code.

In general I first try get a rough image of the program before I start
typing, but this little sticker helps me to figure the correct code
for Octal coded Intel CPU especially for the two-operand instructions.

I wish I could have the stumack for that. It may save time. But it may be
more needed for you, since making errors will break everything?

No, I also got a debugger which reports exceptions and if a program
enters an endless loop then I can hit F12 to terminate it.
A problem may be when I work on the debugger or on exception handlers.

In windows, we did the lazy thing, as you know
and can go on hacking until it appear to work.
I think there are benefits to hacking as well, because your mind can get
into modes of writing, and suddenly something nice and surpricing comes
along. Like when Betov plays guitar :)

Sometimes I also see me working like a "ProbierGrammierer"(GER wordplay).
Yes coincident buggy behaviour often leads to new ideas :)

....
NT did not recognize it after I setup the Os again. I have no idea what
could have took it down.
I focking shave you ass! :D
Billy may take your offer serious :)
<q>
I hope not. I dont recall it happend before. Maybe it was the setup
program. (more likly) I turned a win32 partition, an other one then the
one damaged, into a NTFS partition during setup. Dont laugh. I did NOT do
this myself. I know because the partition I turned evil, was the
systemdrive. And that is an entirely diffrent drive. But I think I did
that many times before, and without any problem then. If you had a similar
problem, would you bother taking the time finding the reason? If so, how
would you proceed? Theres is 60000 files on this small computer.
</q>

On usually heavy fragmented FAT/NT-partition this would be hell of a job.
If I search for a certain vital file then I can find its parts with my
diskeditor and then merge it together to become fully restored, but
if I can download it from elsewher I'd do this instead.
KESYS-FS never stores fragmented, so here also a directory can be
restored if it got lost (even never happened yet).

To overcome all the results of the many crashes I created partitions
on my net-connected PC:
HD-0:
512 MB DOS600,
the rest is KESYS formatted (but still empty yet)
HD-1:
2GB win89 FAT
2GB XPhome NT
62GB winApps NT
62GB my Infobook FAT32
the rest isn't used yet because windoze wont recognise
larger than 128 GB HDs anyway.

So I just need to quick format 2GB whenever a crash occures
and I don't allow the new OS-install to touch any other volume.

__
wolfgang



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