Re: [dev] suckless bignum library

From: FRIGN <>
Date: Thu, 10 Dec 2015 18:57:54 +0100

On Thu, 10 Dec 2015 09:41:21 -0800
Evan Gates <> wrote:

Hey Evan,

> The problem with that is bc can't use a normal bignum library and be
> POSIX compliant as all the internal math is required to be in base 10.
> "Internal computations shall be conducted as if in decimal, regardless
> of the input and output bases, to the specified number of decimal
> digits."[0] That's why implementations of bc tend to have their own
> arbitrary precision stuff built in.

What does the base have to do with the results?
> That being said a suckless bignum library can still be very useful,
> and sbase tends to stray from POSIX in a few places. This may be one
> such place that makes sense to ignore POSIX. For bc we need simple
> arithmetic, sqrt, integer exponents, sine, cosine, arctangent, natural
> log, exponential function, Bessel function of integer order, and a way
> to work with the bc concept of scale.[0] Depending on your performance
> desires many those can either be implemented in the library or in bc
> using a simpler library.
> One last off topic question, should sbase have a bc that calculates,
> or just translates to dc (which is not a POSIX tool, but probably
> useful to have in sbase).

To be honest, I'd go for implementing dc(1) and using the normal bc(1)
based on dc(1). RPN is also easier to implement.



Received on Thu Dec 10 2015 - 18:57:54 CET

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