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Incorrect reinterpret() UInt32 -> Float64 -> UInt64 behaviour on win32 #18019

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alyst opened this issue Aug 13, 2016 · 2 comments
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Incorrect reinterpret() UInt32 -> Float64 -> UInt64 behaviour on win32 #18019

alyst opened this issue Aug 13, 2016 · 2 comments

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@alyst
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alyst commented Aug 13, 2016

The following command (for the context see JuliaData/RData.jl#2)

reinterpret(UInt64, reinterpret(Float64, UInt32[0x1, 0x7ff00000])[1])

on julia-0.5-rc2 on linux 64bit gives

0x7ff0000000000001

but on julia-0.5-rc2 on win 32bit

0x7ff8000000000001

The latter doesn't seem right, because the final UInt64 differs from the input array.

Interestingly, if the first UInt32 is zero, both versions return the correct result.
@yuyichao
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This is a hardware/abi limit, it doesn't preserve the exact bit patter of NaN.

@yuyichao
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Dup of #17195

@yuyichao yuyichao mentioned this issue Aug 13, 2016
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@yuyichao yuyichao mentioned this issue Mar 29, 2017
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@alyst @yuyichao