On Thu, 20 Mar 2025, Jakub Jelinek wrote: > On Thu, Mar 20, 2025 at 03:30:30PM -0500, Robert Dubner wrote: > > Let me find one inky-dink example. Talk amongst yourselves...here we go. > > > > identification division. > > program-id. prog. > > data division. > > working-storage section. > > 77 var8 PIC 999V9(8) COMP-5 . > > 77 var555 PIC 999V99999999 COMP-5 VALUE 555.55555555. > > procedure division. > > move 555.55555555 to var8 > > add 0.00000001 TO var555 giving var8 rounded > > if var8 not equal to 555.55555556 display var8 " should be > > 555.55555556". > > end program prog. > > > > With your patches, the output is > > > > 555.55555555 should be 555.55555556 > > Thanks. > Now, the code certainly could try to do the rounding of the last digits > based on the remaining digits in the string that are being discarded, > if followed by 0-4, don't change anything, if followed by 6-9, increase > last digit, if followed by 5 and any non-zero digit, increase too, if followed > by 5 and all zeros, round to even. > But I'm afraid it can have double rounding, when round_to_decimal rounds > for the precision 33 printing something e.g. with 49999999999999999999 at > the end to 500000000000 and this second rounding again.
I think this must go wrong at a different place than the previous output thing given it's the if var8 not equal to 555.55555556 test that misbehaves. So it might be a similar issue at the input side (I was not very careful when converting the string stuff, esp. with regard to the precision specifiers in the format strings). > So I really think we should go to mpfr, I can implement it tomorrow unless > Richi wants to do that. Go to mpfr for the string conversions? Yeah, maybe that's a good idea. Richard.
