libm: fix double rounding description

[www] / libm / index.html

diff --git a/libm/index.html b/libm/index.html
index 5832554..fa908a3 100644 (file)
--- a/libm/index.html
+++ b/libm/index.html
@@ -146,7 +146,7 @@ m68k and m88k cpus use different ld80 than the intel ones)
 
 
 <ul>
-<li>Double rounding (x87 issue):
+<li>Double rounding:
 <p>
 If a value rounded twice the result can be different
 than rounding just once.
@@ -162,10 +162,12 @@ results in extended precision, this only affects x87 instructions, not see2 etc)
 (afaik freebsd and openbsd use double precision by default)
 <p>
 So x = a+b may give different results depending on
-the fpu setting.
+the x87 fpu precision setting.
 (only happens in round to nearest rounding mode,
 but that's the most common one)
 <p>
+(double rounding can happen with float vs double as well)
+<p>
 C99 annex F prohibits double rounding,
 but that's non-normative.
 
@@ -259,7 +261,7 @@ different precision than at runtime).
 C99 actually allows most of these optimizations
 but they can be turned off with STDC pragmas (see
 <a href="http://repo.or.cz/w/c-standard.git/blob_plain/HEAD:/n1256.html#6.10.6">6.10.6</a>).
-Unfortunately <a href="http://gcc.gnu.org/c99status.html">gcc does not support these pragmas</s>.
+Unfortunately <a href="http://gcc.gnu.org/c99status.html">gcc does not support these pragmas</a>.
 <p>
 FENV_ACCESS ON tells the compiler that the code wants
 to access the floating point environment (eg. set different rounding mode)