Re: maximum value of a scalar

For 32-bit version of Perl, the maximum integer (without using bigint or similar) that can be stored precisely is -2⁵³ on the negative side and 2⁵³ on the positive side.

>perl -e"printf qq{%.f\n}, 2**53+$_ for +1,0,-1"
9007199254740992
9007199254740992
9007199254740991

>perl -e"printf qq{%.f\n}, -2**53+$_ for +1,0,-1"
-9007199254740991
-9007199254740992
-9007199254740992
[download]

build settings	Max positive integer	Max negative integer
32-bit ints and double floats	2⁵³ = 9_007_199_254_740_992	-2⁵³ = -9_007_199_254_740_992
64-bit ints and double floats	2⁶⁴-1 = 18_446_744_073_709_551_615	-2⁶³ = 9_223_372_036_854_775_808
64-bit ints and quadruple floats	2¹¹³ = 10_384_593_717_069_655_257_060_992_658_440_192	-2¹¹³ = -10_384_593_717_069_655_257_060_992_658_440_192

Some operators (notably the bit operators) won't work with every number in that range.
Some C extensions won't work with every number in that range.

Comment on Re: maximum value of a scalar Download Code

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Re^2: maximum value of a scalar by Anonymous Monk on Mar 01, 2009 at 06:11 UTC
I'm trying to compile for quadruple floats, and it's not obvious to me what the parameter is during configure. Suggestions? Thanks, Scott	[reply]
Re^3: maximum value of a scalar by syphilis (Archbishop) on Mar 01, 2009 at 09:38 UTC
I'm trying to compile for quadruple floats What is your compiler's C data type for these "quadruple floats" ? I had assumed that, if a C compiler could handle "quadruple floats", it would be handling them as "long doubles" - in which case building with `-Duselongdouble` might do the trick. Cheers, Rob	[reply] [d/l]
Re^4: maximum value of a scalar by Anonymous Monk on Mar 02, 2009 at 05:57 UTC
I'm using gcc on linux. Not sure what the compiler's data type for "quadruple floats" is, though "long doubles" are 16 bytes accordint to ./Configure. It seems that (2^128) should be enough. I have long doubles turned on, and general 64 bit turned on, but I still max out at 2^64 instead of 2^113. Is there an additional gcc flag I can pass in that anyone knows of to get the 2^113 limit? Thanks! Scott	[reply]
Re^5: maximum value of a scalar by syphilis (Archbishop) on Mar 02, 2009 at 17:48 UTC
Re^3: maximum value of a scalar by ikegami (Patriarch) on Mar 01, 2009 at 06:43 UTC
Sorry, none. I have no knowledge on the topic.	[reply]