Hi Dwayne, This is not something you should ask for on the Piclist.=20 Everybody else, please, no helpful replies. Thanks, Bob On Fri, Oct 19, 2012, at 11:52 AM, Dwayne Reid wrote: > Good day to all. >=20 > I had a look at the code at the Hacker's Delight website and was=20 > sufficiently impressed to look for a copy. I'm in Canada and, as=20 > usual, prices are higher than in the USA. However, Chapter Indigo=20 > will sell me an eBook for Can $37 instead of Can $60 for the paper > version. >=20 > The problem with purchasing an eBook from Chapters is that it is=20 > encumbered with Adobe DRM. I don't know if that means that it won't=20 > work with my Sony eBook reader but I do know that I am restricted in=20 > where and when I can read it. In particular, I want to be able to=20 > seamlessly switch between copies on my work computer, my home=20 > computer and my laptop. >=20 > I have found a most likely illegal electronic copy on the web but I'd=20 > rather purchase a legal copy and strip out the DRM protection. >=20 > Can anyone point me in the direction as to how I might do that? >=20 > Many thanks! >=20 > dwayne >=20 >=20 > At 12:07 PM 10/19/2012, Joe Mickley wrote: > >:Mark > > > >Thank you for the pointer to the book. I went out this AM and bought a > >copy. A little pricey, but there is a LOT > >of stuff in there in additon to the divide info. I'm wading thru it rig= ht > >now (lots of choices). I'll let the piclist > >community know that I find out. > > > >Regards > >Joe Mickley > > > >----- Original Message ----- > >From: "Mark Rages" > >To: "Microcontroller discussion list - Public." > >Sent: Wednesday, October 17, 2012 3:42 PM > >Subject: Re: [PIC] Fast 32 bit by 32 bit divide in a dsPIC30F > > > > > > > On Wed, Oct 17, 2012 at 12:56 PM, Joe Mickley > > > wrote: > > >> I am using a dsPIC30F3012 (writing in ASM, not C) on a project with = very > > >> fast loop execution (<20 uSec in some cases) > > >> and need an effecient 32 bit by 32 bit unsigned divide algorithm. T= he > > >> dsPIC30F family has organic 16 by 16 divide > > >> instruction (DIV.U and DIV.UD) and I would like to create a 32 by 32 > > >> using > > >> that instruction set. > > >> > > >> The traditional 32 by 32 divide using a shift/subtract (restoring) > > >> algorithms is slow (about 400 instruction cycles nominal). It > > >> should be possible to break the 32 by 32 into a set of 16 by 16 > > >> operations, > > >> then combine the partials back into a 32 by 32 > > >> result, but I lack the knowledge of how to do or drive this. The > > >> dsPIC30F > > >> divide routine is fast (18 cycles, so > > >> any use of itshould have a marked improvement) > > >> > > >> I need an unsigned divide, but could live with a signed divide as th= e > > >> magnitude of numbers I am working with are less than > > >> 2^30. Remainder or lack of is not critical. If I need it I could d= erive > > >> a > > >> remainder externally to the routine. > > > > > > This is discussed in Section 9-2 of Hacker's Delight, 2nd edition. I= t > > > is a page and a half of C code. > > > > > >>From the book: "The details are surprisingly complicated." > > > > > > You can read the code if go to the book's page at Amazon and "search > > > inside this book" for "Multiword Division". But buy the book if you > > > can. > > > > > > -- > > > Regards, > > > Mark > > > markrages@gmail > > > -- > > > http://www.piclist.com PIC/SX FAQ & list archive > > > View/change your membership options at > > > http://mailman.mit.edu/mailman/listinfo/piclist > > > >-- > >http://www.piclist.com PIC/SX FAQ & list archive > >View/change your membership options at > >http://mailman.mit.edu/mailman/listinfo/piclist >=20 >=20 > --=20 > Dwayne Reid > Trinity Electronics Systems Ltd Edmonton, AB, CANADA > (780) 489-3199 voice (780) 487-6397 fax > www.trinity-electronics.com > Custom Electronics Design and Manufacturing >=20 > --=20 > http://www.piclist.com PIC/SX FAQ & list archive > View/change your membership options at > http://mailman.mit.edu/mailman/listinfo/piclist --=20 http://www.fastmail.fm - Choose from over 50 domains or use your own --=20 http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .