Re: High-precision fixed point math

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#588

From: B Summers .com
Date: Wed, 18 Sep 2002 03:56

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<cough>...array...<cough>....


"Mike K" <mkipper@rogers.com> wrote in message
news:w8Rh9.77700$561.55900@news02.bloor.is.net.cable.rogers.com...
> Hi,
>
> To start off, yes this is a school question. The question is as follows:
> Write a C++ program to calculate and print the square root of an integer
to
> 40 decimal points.
> To me, this seems like a Newton's Method type problem, except for the fact
> that my computer can't do more than MSVC++'s 80-bit/10-byte long double.
> So, I was thinking of writing a template class which holds BCD number
> information in nibbles (full bytes for now, optimize later). Then, math is
> performed through the nibble array.
> Is this sane? Is there a better way to do it? I don't want to waste my
time
> reinventing the wheel, if there's already a better answer out there.
> I did find, through my travels, a library called BigInt.h, which kind of
> implements the same kind of idea:
>
> #define BIGINT_TOTAL_BITS 128       // Produces 38   decimal digits
> #define BIGINT_BASE_BITS 32         // Number of bits in base type
> #define BIGINTSIZE (BIGINT_TOTAL_BITS / BIGINT_BASE_BITS)
> typedef unsigned long BIGINT_BASE;  // The base type.
> public:
>   BIGINT_BASE data[BIGINTSIZE];     /* Little endian data */
>
> But I couldn't get it to work properly.
>
> Thanks for your help!
>
> Michael
> -----
>
>
>

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