Re: [perl #38887] Result of INFINITY or NAN stringification is platform dependent
On Sun, Jul 16, 2006 at 12:49:27PM +0100, Ron Blaschke wrote: > On Win32 the implementation is simple because the IEEE recommended > functions _finite and _isnan are supported. I'm thinking about adding a > test for these functions and use them. But what should happen if they > are not there? nan == nan isn't true, so that ought to be a portable test for a NaN (although Intel's compiler's default optimisation setting is buggy in this respect) I don't know of a good way to test for inf. Nicholas Clark
Re: [perl #38887] Result of INFINITY or NAN stringification is platform dependent
On Wed, Jul 26, 2006 at 01:21:11PM -0700, Bill Coffman wrote: > That being said, you can optimize by looking at the bits. Wikipedia > explains IEEE-754 http://en.wikipedia.org/wiki/IEEE_754 > First, you have to be aware if the machine is big or little-endian, second, Beware. It's legal for the endianness of the word order in memory to differ from the endianness of the byte order within those words. Nicholas Clark
Re: [perl #38887] Result of INFINITY or NAN stringification is platform dependent
Bill Coffman wrote: > There is no platform independent way to produce "NaN" or "Inf", so IMHO, > you > did it the only way it can be done. > > That being said, you can optimize by looking at the bits. Wikipedia > explains IEEE-754 http://en.wikipedia.org/wiki/IEEE_754 Many thanks for your thoughts, Bill. Your suggestion seems a lot easier than all this platform probing stuff I had in mind. For platforms that don't use IEEE 754, like the VAX you mentioned, I guess we can always come up with something else if the need arises. > Personally, I'd like to see the "i" in "inf" capitolized or the "N"s in > "NaN" lower case. I like capital I for Inf. Sounds good to me. I'll change it to your suggested "Inf" and "NaN." Thanks, Ron
Re: [perl #38887] Result of INFINITY or NAN stringification is platform dependent
On 7/26/06, Ron Blaschke <[EMAIL PROTECTED]> wrote: I'm looking into this issue and would like to ask for some advice. I have added the following platform dependent functions. int Parrot_math_isnan(double) int Parrot_math_finite(double) On Win32 the implementation is simple because the IEEE recommended functions _finite and _isnan are supported. I'm thinking about adding a test for these functions and use them. But what should happen if they are not there? Then I changed Parrot_sprintf_format in spf_render.c to use Parrot_math_isnan and Parrot_math_finite to render "NaN", "-inf" and "inf" directly. Is this a good way to solve this? There is no platform independent way to produce "NaN" or "Inf", so IMHO, you did it the only way it can be done. That being said, you can optimize by looking at the bits. Wikipedia explains IEEE-754 http://en.wikipedia.org/wiki/IEEE_754 First, you have to be aware if the machine is big or little-endian, second, look at the exponent bits, if they are all set, this is not a normal number (either +Inf, -Inf, or NaN, depending on mantissa and sign bit). Unless you're targeting non-ieee-754 systems like the VAX (an old computer), this is garanteed to be portable. I wouldn't bother with any platform specific functions, as they are all different. Just look at the bits. (gcc uses isnan, isinfinite, ... but I think you have to compile with the -c99 flag and solaris does it a little different, etc). I recently did something similar in PDL. If "looking at the bits" is not helpful, I can give you a little more detail (hint "struct union"). If you really don't want to look at the bits, I notice that gcc does have an "isnormal()" function you can use, but again you have the portability issues. Personally, I'd like to see the "i" in "inf" capitolized or the "N"s in "NaN" lower case. I like capital I for Inf. Good luck, Here's a sample (which should make its way into some tests): >type test.pir .sub main # -INF set N0, 0.0 ln N1, N0 print N1 print "\n" # +INF abs N2, N1 print N2 print "\n" # NaN set N3, -1.0 sqrt N4, N3 print N4 print "\n" .end # trunk >parrot test.pir -1.#INF00 1.#INF00 -1.#IND00 # local >parrot test.pir -inf inf NaN Thanks, Ron -- Bill Coffman ~~~_\\\|/ ~~~-(@ @) =oOO=(_)==OOo===
[perl #38887] Result of INFINITY or NAN stringification is platform dependent
I'm looking into this issue and would like to ask for some advice. I have added the following platform dependent functions. int Parrot_math_isnan(double) int Parrot_math_finite(double) On Win32 the implementation is simple because the IEEE recommended functions _finite and _isnan are supported. I'm thinking about adding a test for these functions and use them. But what should happen if they are not there? Then I changed Parrot_sprintf_format in spf_render.c to use Parrot_math_isnan and Parrot_math_finite to render "NaN", "-inf" and "inf" directly. Is this a good way to solve this? Here's a sample (which should make its way into some tests): >type test.pir .sub main # -INF set N0, 0.0 ln N1, N0 print N1 print "\n" # +INF abs N2, N1 print N2 print "\n" # NaN set N3, -1.0 sqrt N4, N3 print N4 print "\n" .end # trunk >parrot test.pir -1.#INF00 1.#INF00 -1.#IND00 # local >parrot test.pir -inf inf NaN Thanks, Ron
[perl #38887] Result of INFINITY or NAN stringification is platform dependent
I'm looking into this issue and would like to ask for some advice. I have added the following platform dependent functions. int Parrot_math_isnan(double) int Parrot_math_finite(double) On Win32 the implementation is simple because the IEEE recommended functions _finite and _isnan are supported. I'm thinking about adding a test for these functions and use them. But what should happen if they are not there? Then I changed Parrot_sprintf_format in spf_render.c to use Parrot_math_isnan and Parrot_math_finite to render "NaN", "-inf" and "inf" directly. Is this a good way to solve this? Here's a sample (which should make its way into some tests): >type test.pir .sub main # -INF set N0, 0.0 ln N1, N0 print N1 print "\n" # +INF abs N2, N1 print N2 print "\n" # NaN set N3, -1.0 sqrt N4, N3 print N4 print "\n" .end # trunk >parrot test.pir -1.#INF00 1.#INF00 -1.#IND00 # local >parrot test.pir -inf inf NaN Thanks, Ron
[perl #38887] Result of INFINITY or NAN stringification is platform dependent
# New Ticket Created by Ron Blaschke # Please include the string: [perl #38887] # in the subject line of all future correspondence about this issue. # https://rt.perl.org/rt3/Ticket/Display.html?id=38887 > .sub main # produce INFINITY (is there a constant for that?) set N0, 0.0 ln N1, N0 print N1 print "\n" # produce NAN (is there a constant for that?) set N0, -1.0 sqrt N1, N0 print N1 print "\n" .end On Windows with Visual C++ 8.0 above code prints >parrot test.pir -1.#INF00 -1.#IND00 On UNIXish platforms it's probably "-inf" and "-nan". That's why F currently fails on Windows: It expects "-inf" on stringification. t\pmc\complexok 13/50 t\pmc\complexNOK 30# Failed test (t\pmc\complex.t at line 997) # got: ' # ln(0+0i) # got -1.#INF00+0.00i # not -inf+0.00i # done # ' # expected: 'done # ' t\pmc\complexok 50/50# Looks like you failed 1 test of 50. t\pmc\complexdubious Test returned status 1 (wstat 256, 0x100) DIED. FAILED test 30 Failed 1/50 tests, 98.00% okay (less 3 skipped tests: 46 okay, 92.00%) Failed Test Stat Wstat Total Fail Failed List of Failed --- t\pmc\complex.t1 256501 2.00% 30 3 subtests skipped. Failed 1/1 test scripts, 0.00% okay. 1/50 subtests failed, 98.00% okay.
