Re: port-mips/57680: printf("%.1f") shows wrong results on R3000mipseb

[RVP <rvp%SDF.ORG@localhost>]

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

From: RVP <rvp%SDF.ORG@localhost>
To: gnats-bugs%netbsd.org@localhost
Cc: tsutsui%ceres.dti.ne.jp@localhost
Subject: Re: port-mips/57680: printf("%.1f") shows wrong results on
 R3000mipseb
Date: Fri, 3 Nov 2023 12:49:55 +0000 (UTC)

 On Fri, 3 Nov 2023, Izumi Tsutsui wrote:
 
 > Now I've tried it on both NWS-3470 (R3000 + R3010) and NWS-5000 (R4400):
 >
 > On NWS-3470:
 > ---
 > news3470-% cc -I/s/netbsd-9/src/lib/libc/gdtoa/ -I/s/netbsd-9/src/lib/libc/arch/mips/gdtoa/ -DDEBUG -DHonor_FLT_ROUNDS -DNO_LONG_LONG -o m m.c /s/netbsd-9/src/lib/libc/gdtoa/gdtoa.c /s/netbsd-9/src/lib/libc/gdtoa/dmisc.c
 > news3470-% ./m
 > .O
 > 40490FD0
 > 3.0
 > 439D145A
 > ?.0
 > 44C45970
 > news3470-% grep ^cpu0 /var/run/dmesg.boot
 > cpu0 at mainbus0: MIPS R3000 CPU (0x220) Rev. 2.0 with MIPS R3010 FPC Rev. 2.0
 > cpu0: 64KB/4B direct-mapped Instruction cache, 64 TLB entries
 > cpu0: 64KB/4B direct-mapped write-through Data cache
 > news3470-%
 > ---
 >
 > On NWS-5000:
 > ---
 > (copy the above "m" binary from NWS-3470)
 > news5000-% ./m
 > 3.1
 > 40490FD0
 > 314.1
 > 439D145A
 > 1570.7
 > 44C45970
 > news5000-% % grep ^cpu0 /var/run/dmesg.boot
 > cpu0 at mainbus0: MIPS R4400 CPU (0x450) Rev. 5.0 with MIPS R4010 FPC Rev. 0.0
 > cpu0: 48 TLB entries, 16MB max page size
 > cpu0: 16KB/16B direct-mapped L1 instruction cache
 > cpu0: 16KB/16B direct-mapped write-back L1 data cache
 > cpu0: 1024KB/64B direct-mapped write-back L2 unified cache
 > news5000-%
 >
 > ---
 > Izumi Tsutsui
 >
 
 Interesting. The _same_ binary behaves differently. Rules out a compiler bug
 --well, almost.
 
 Can you try a new binary with /usr/src/lib/libc/gdtoa/misc.c compiled in as
 well:
 
 cc -I/usr/src/lib/libc/gdtoa/ -I/usr/src/lib/libc/arch/mips/gdtoa/ \
    -DDEBUG -DHonor_FLT_ROUNDS -DNO_LONG_LONG -o m m.c \
    /usr/src/lib/libc/gdtoa/dtoa.c \
    /usr/src/lib/libc/gdtoa/dmisc.c \
    /usr/src/lib/libc/gdtoa/misc.c
 
 This way, the resulting binary won't pickup _any_ gdtoa funcs. from libc.
 (Previously, the stuff in misc.c came from the libc on the running machine
   which may have been optimized.)
 
 -RVP