i'm looking at this code segment

sbb ax, ax
sbb ax, 0FFFFh

and i was wondering what the point of the line sbb ax,ax is. wouldn't that just set ax to 0?

subtract with borrow can set ax to zero if there were no carry over
or to -1 if there was a carry over in one of the earlier operation

suppose 10 was subtracted from 9 in one of the earlier operation
sbb ax,ax will become -1

assemble this nippet in ollydbg arbitrarily some where and single step through it to understand what can be possible results



oh btw last but not least get the intel manuals from intel for free (postage prepaid by intel it comes to your door in max three days via fedex or amd manuals ( i believe amd too gives out those manulas for free posted to your door not sure)

and RTFM

@blabberer -> i think they stopped the delivery thing, its only available as pdf download now... if not, have u still got the link to them?

The last couple of people who did the delivery thing got sent a cd with the manuals in pdf format rather than the manuals, so easier to just download them.

i ordered them long ago im not aware of the latest developments but even i had to keep stalking the url because they accept orders only if they have them ready in print and shippable

just because you asked i clicked a few bookmarks to see if they are still valid

and they kinda redirect me to this page now

http://developer.intel.com/products/processor/manuals/index.htm

following the order printed copy


you get this



so i think it is still alive and kicking try mailing and see what you recieve

It's part of an Asm idiom. Might be the ! operator or something else, you'll have to post the instructions before it.

Thanks for that link. I just submitted a request for delivery outside the USA, so I'll let you know what happens. It's normally much harder to get this stuff if you're not in mainland USA.

I'm in the UK, and they sent me a cd with all the manuals on via Fedex. Same happened to a few other people I know in the UK. So they will post outside the US, but whether they'll send heavy manuals that way is unknown, so let us know when/if you receive something.

Hi,

just to let you know, I reside in Germany and I got the Intel manuals as printed copies last week. It was a pretty heavy package filled with six books, delivered by FedEx. All that at no cost. I asked for printed copies and I got them, so maybe you have to express clearly that you don't want a CD. I'am glad I got it printed, because reading a book is imo much more conveniant then reading on a screen. Maybe you should try it again (with a friend, girlfriend, whatever as recipient). I wish you good luck

Best regards
darkelf

darkelf,

cool, I am "near" you, and will do it, too

LLXX



wouldn't that correctly be for example a C idiom? an idiom defines a programming language specific pattern on a lower abstraction layer (ie compiled code -> asm)

just 2 cents, I could be wrong, but this is how i was used to use the term idiom so far

cheers, 0xf001

I am at about 10 time zone away from U.S and i recieved the printed copy
not cds when i ordered them (and that was about two and half years ago)
free (the local ppl took about a dollar as local entry tax pffft but intel couldnt have thought about that and couldn't have compensated it so as far as intel is concerned i recieved them absolutely free) and that to within three days of ordering 5 books via fedex

and the email address ( i just recovered the corrrespondance from some junked folder) is same as i pointed above

I ordered books some months ago, from Europe. I agree with the fact they send paper version when they have some ready.

thanks blabberer

Hmmm, it seems I should have to try again and hope I get printed ones this time