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Date:	Fri, 19 May 2000 14:15:30 +0200 (MET DST)
From:	Hans-Bernhard Broeker <broeker AT physik DOT rwth-aachen DOT de>
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To:	djgpp-workers AT delorie DOT com
Subject:	Re: rand() in libc
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On Fri, 19 May 2000, Martin Stromberg wrote:

> Ok, how doI  easily say 2^-16, 2^-32 and 2^-48 to the compiler? Is it
> ok to use pow(2, -16) etc. (efficiency)?

No. Use ldexp(), it's usually much more efficient than pow(). If there is
no special support for the operation 'multiply by 2^exponent implemented
in the FP hardware, the library implementor will fall back to using pow(),
but by using ldexp, you're giving him a chance to provide a better method.

In a nutshell, ldexp() is for floating point types what bitshifts are
for integers.

Hans-Bernhard Broeker (broeker AT physik DOT rwth-aachen DOT de)
Even if all the snow were burnt, ashes would remain.

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