add error with bignumbers in lua

Question

Hi guys, i have a problems doing the operation add with numbers of 64 bits

the following code return a incorrect value:

report_failure(string.format("%16x", ((0xfefefefe * math.pow(2,32))+0xabababab)))

this code should be return a window with the value fefefefeabababab, but return fefefefeababa800

any idea?

Answer 1

Lua stores all numbers (internally) as floats (by default double-precision floating point numbers). So you can't do 64-bit math very well in Lua. For some more details see this email on the wireshark-users mailing list.