Re: port-mips/57680: printf("%.1f") shows wrong resultsonR3000mipseb

[Izumi Tsutsui <tsutsui%ceres.dti.ne.jp@localhost>]

The following reply was made to PR port-mips/57680; it has been noted by GNATS.

From: Izumi Tsutsui <tsutsui%ceres.dti.ne.jp@localhost>
To: rokuyama.rk%gmail.com@localhost
Cc: gnats-bugs%netbsd.org@localhost, tsutsui%ceres.dti.ne.jp@localhost
Subject: Re: port-mips/57680: printf("%.1f") shows wrong resultsonR3000mipseb
Date: Sat, 4 Nov 2023 19:16:30 +0900

 > >   Unless some MIPS guru has proper idea how this issue should be fixed,
 > >   I'd like to commit workaround fix to disable -DHonor_FLT_ROUNDS in
 > >   src/lib/libc/gdtoa/Makefile.inc in ${MACHINE_CPU}=="mips" case.
 > 
 > (1) How about -current or netbsd-10, which have GCC 10.5?
 > 
 >      Less likely, but if this is a temporal problem for specific
 >      versions of GCC, we can restrict the workaround to netbsd-9.
 
 I have not tried it, but last time I tried netbsd-10 kernel
 on NWS-3260 it was very unstable and looked lost software interrupts
 many times, so I'm currently testing NWS-3260 on netbsd-9.
 
 I doubt this problem was really compiler issue and
 I wonder if it's okay to assume "FE_TONEAREST" is default
 because FE_TOZERO works.
 
 > (2) Can we exclude ``mipsn{,64}e[bl]''? -current and netbsd-10 have
 >      ${MACHINE_MIPS64} macro for this purpose, but netbsd-9 does not :(
 
 What's your motivation?
 
 Performance? If so, is it visible or measurable?
 Consistency? If so, is there any rationale of Honor_FLT_ROUNDS
 implementation?  Actually we already have an exception (vax).
 
 If you have a working patch to achive your intention in both
 HEAD and release branches, it's fine.  If not, sorry I don't
 have motivation to prepare such complexities.
 
 I'm trying to fix visible issue (and real problems like invalid
 strings stored in /etc/ntp.conf etc.).  If you want possible
 performace or design consistency, it should be measured or
 defined by people who want it, because we are on Tier-II ports
 "keeping it working is the responsibility of the user community."
  https://wiki.netbsd.org/ports/
 
 ---
 Izumi Tsutsui