Re: ffi.cast: weird behaviour
- From: Mike Pall <mike-1311@xxxxxxxxxx>
- To: luajit@xxxxxxxxxxxxx
- Date: Fri, 22 Nov 2013 04:46:31 +0100
Daurnimator wrote:
> This is what I ended up with: https://gist.github.com/daurnimator/7582543
> Hopefully I didn't overlook anything else...
Wrong mantissa condition, use of uint32_t, endianess issues,
efficiency issues.
local cast, band = ffi.cast, bit.band
local lohi_p = ffi.typeof("struct { int32_t "..(ffi.abi("le") and "lo, hi" or
"hi, lo").."; } *")
local function double_isnan(p)
local q = cast(lohi_p, p)
return band(q.hi, 0x7ff00000) == 0x7ff00000 and
bit.bor(q.lo, band(q.hi, 0xfffff)) ~= 0
end
--Mike
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