From: Szabolcs Nagy <nsz@port70.net>
To: musl@lists.openwall.com
Subject: [PATCH] fix float formatting of some exact halfway cases
Date: Wed, 12 Oct 2016 00:49:59 +0200 [thread overview]
Message-ID: <20161011224959.GO28065@port70.net> (raw)
in nearest rounding mode exact halfway cases were not following the
round to even rule if the rounding happened at a base 1000000000 digit
boundary of the internal representation and the previous digit was odd.
e.g. printf("%.0f", 1.5) printed 1 instead of 2.
---
src/stdio/vfprintf.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/src/stdio/vfprintf.c b/src/stdio/vfprintf.c
index e439a07..ff65295 100644
--- a/src/stdio/vfprintf.c
+++ b/src/stdio/vfprintf.c
@@ -343,7 +343,8 @@ static int fmt_fp(FILE *f, long double y, int w, int p, int fl, int t)
if (x || d+1!=z) {
long double round = 2/LDBL_EPSILON;
long double small;
- if (*d/i & 1) round += 2;
+ if ((*d/i & 1) || (i==1000000000 && d>a && (d[-1]&1)))
+ round += 2;
if (x<i/2) small=0x0.8p0;
else if (x==i/2 && d+1==z) small=0x1.0p0;
else small=0x1.8p0;
--
2.10.0
next reply other threads:[~2016-10-11 22:49 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-10-11 22:49 Szabolcs Nagy [this message]
2016-10-20 5:55 ` Rich Felker
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