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- Subject: Re: [ANN] Lua 5.2.0 (rc7) now available
- From: KHMan <keinhong@...>
- Date: Sat, 10 Dec 2011 05:03:37 +0800
On 12/10/2011 12:20 AM, Roberto Ierusalimschy wrote:
and the simple tests:
print(2^3 - 8)
print(3^4 - 81)
These all should be zero. It really seems that the 'pow' function
from the C library is broken.
Correction to my previous post, usage of 2 ** (y log2(x)) for x86
may not be the real reason. For one, the value I got
(-2.84217e-014) had the wrong sign, and secondly, for 2^3-8, the
calculation is exact.
FWIW, for the result -2.84217e-014, the IEEE754 double byte value
of the 81-something value versus the normally expected result is:
0x40543FFFFFFFFFFF => short of -2.84217e-014
0x4054400000000000 => 81 exact
so Tymur's result should be off by 1 in the other direction,
Sorry for the noise. But a non-exact value for 2^3-8 seems pretty
bad for business, though...
Kein-Hong Man (esq.)
Kuala Lumpur, Malaysia