Re: [PATCH #2] Re: [PATCH] numeric.c:S_mulexp10 -- quit whenyou can

At 03:27 PM 6/19/2002 +0100, Hugo van der Sanden wrote:
>"Craig A. Berry" <craigberry@mac.com> wrote:

>:$ perl -e "my $x = 100.000000000000000001; print $x;"
>:0
>
>Could you try the patch below? It doesn't break anything here, but
>I can't easily coerce my platform to use the new codepath.


Unfortunately it had no effect on the problem, which seems to occur not in 
the loop you patched but further down in the call that looks like:


    /* now apply the exponent */
    exponent += expextra;
    result = S_mulexp10(result, exponent);

The values of the parameters right before the call are

NUMERIC\Perl_my_atof2\result:   0.100000000000000E+21
NUMERIC\Perl_my_atof2\exponent: -18

We do hit your new check 4 times, though we never pass the test and execute 
the "reduce precision" code.  Here's the output of the relevant values each 
time we do the check:

DBG> set module numeric
DBG> set break Perl_my_atof2\%line 43959 do (examine testresult, ipart, i, part[ipart-i], expextra)
DBG> g
break at NUMERIC\Perl_my_atof2\%LINE 43959
 43959:        if (testresult == 0.0 && part[ipart - i] != 0 && expextra < 0) {
NUMERIC\Perl_my_atof2\%LINE 43957\testresult:   0.000000000000000
NUMERIC\Perl_my_atof2\ipart:    0
NUMERIC\Perl_my_atof2\i:        0
NUMERIC\Perl_my_atof2\part[0]:  0
NUMERIC\Perl_my_atof2\expextra: 0
DBG> g
break at NUMERIC\Perl_my_atof2\%LINE 43959
 43959:        if (testresult == 0.0 && part[ipart - i] != 0 && expextra < 0) {
NUMERIC\Perl_my_atof2\%LINE 43957\testresult:   1.00000000000000
NUMERIC\Perl_my_atof2\ipart:    2
NUMERIC\Perl_my_atof2\i:        0
NUMERIC\Perl_my_atof2\part[2]:  1
NUMERIC\Perl_my_atof2\expextra: -18
DBG> g
break at NUMERIC\Perl_my_atof2\%LINE 43959
 43959:        if (testresult == 0.0 && part[ipart - i] != 0 && expextra < 0) {
NUMERIC\Perl_my_atof2\%LINE 43957\testresult:   0.000000000000000
NUMERIC\Perl_my_atof2\ipart:    2
NUMERIC\Perl_my_atof2\i:        1
NUMERIC\Perl_my_atof2\part[1]:  0
NUMERIC\Perl_my_atof2\expextra: -18
DBG> g
break at NUMERIC\Perl_my_atof2\%LINE 43959
 43959:        if (testresult == 0.0 && part[ipart - i] != 0 && expextra < 0) {
NUMERIC\Perl_my_atof2\%LINE 43957\testresult:   0.100000000000000E+21
NUMERIC\Perl_my_atof2\ipart:    2
NUMERIC\Perl_my_atof2\i:        2
NUMERIC\Perl_my_atof2\part[0]:  100000000
NUMERIC\Perl_my_atof2\expextra: -18
DBG> g
0
%DEBUG-I-EXITSTATUS, is '%SYSTEM-S-NORMAL, normal successful completion'

• [PATCH #2] Re: [PATCH] numeric.c:S_mulexp10 -- quit when you can by Craig A. Berry
• Re: [PATCH #2] Re: [PATCH] numeric.c:S_mulexp10 -- quit when youcan by Craig A. Berry
• Re: [PATCH #2] Re: [PATCH] numeric.c:S_mulexp10 -- quit when you can by Hugo van der Sanden
• Re: [PATCH #2] Re: [PATCH] numeric.c:S_mulexp10 -- quit whenyou can by Craig A. Berry
• Re: [PATCH #2] Re: [PATCH] numeric.c:S_mulexp10 -- quit when you can by Hugo van der Sanden
• Re: [PATCH #2] Re: [PATCH] numeric.c:S_mulexp10 -- quit whenyou can by Craig A. Berry
• Re: [PATCH #2] Re: [PATCH] numeric.c:S_mulexp10 -- quit when you can by Hugo van der Sanden
• Re: [PATCH #2] Re: [PATCH] numeric.c:S_mulexp10 -- quit when you can by Hugo van der Sanden