Am 06.11.19 um 11:39 schrieb Georg-Johann Lay:
Ping #1
Am 31.10.19 um 22:55 schrieb Georg-Johann Lay:
Hi, this adds the possibility to enable IEEE compatible double
and long double support in avr-gcc.
It supports 2 configure options
--with-double={32|64|32,64|64,32}
--with-long-double={32|64|32,64|64,32|double}
which select the default layout of these types and also chose
which mutlilib variants are built and available.
These two config option map to the new compiler options
-mdouble= and -mlong-double= which are new multilib options.
The patch only deals with option handling and multilib bits,
it does not add any double functionality. The double support
functions are supposed to be provided by avr-libc which also hosts
all the float stuff, including __addsf3 etc.
Ok for trunk?
Johann
..and here is the addendum that documents the new configure options.
Index: gcc/doc/install.texi
===================================================================
--- gcc/doc/install.texi (revision 277236)
+++ gcc/doc/install.texi (working copy)
@@ -2277,15 +2277,45 @@ omitted from @file{libgcc.a} on the assu
@samp{newlib}.
@item --with-avrlibc
-Specifies that @samp{AVR-Libc} is
-being used as the target C library. This causes float support
+Only supported for the AVR target. Specifies that @samp{AVR-Libc} is
+being used as the target C@tie{} library. This causes float support
functions like @code{__addsf3} to be omitted from @file{libgcc.a} on
the assumption that it will be provided by @file{libm.a}. For more
technical details, cf. @uref{http://gcc.gnu.org/PR54461,,PR54461}.
-This option is only supported for the AVR target. It is not supported for
+It is not supported for
RTEMS configurations, which currently use newlib. The option is
supported since version 4.7.2 and is the default in 4.8.0 and newer.
+@item --with-double=@{32|64|32,64|64,32@}
+@itemx --with-long-double=@{32|64|32,64|64,32|double@}
+Only supported for the AVR target since version@tie{}10.
+Specify the default layout available for the C/C++ @samp{double}
+and @samp{long double} type, respectively. The following rules apply:
+@itemize
+@item
+The first value after the @samp{=} specifies the default layout (in bits)
+of the type and also the default for the @option{-mdouble=} resp.
+@option{-mlong-double=} compiler option.
+@item
+If more than one value is specified, respective multilib variants are
+available, and @option{-mdouble=} resp. @option{-mlong-double=} acts
+as a multilib option.
+@item
+If @option{--with-long-double=double} is specified, @samp{double} and
+@samp{long double} will have the same layout.
+@item
+If the configure option is not set, it defaults to @samp{32} which
+is compatible with older versions of the compiler that use non-standard
+32-bit types for @samp{double} and @samp{long double}.
+@end itemize
+Not all combinations of @option{--with-double=} and
+@option{--with-long-double=} are valid. For example, the combination
+@option{--with-double=32,64} @option{--with-long-double=32} will be
+rejected because the first option specifies the availability of
+multilibs for @samp{double}, whereas the second option implies
+that @samp{long double} --- and hence also @samp{double} --- is always
+32@tie{}bits wide.
+
@item --with-nds32-lib=@var{library}
Specifies that @var{library} setting is used for building @file{libgcc.a}.
Currently, the valid @var{library} is @samp{newlib} or @samp{mculib}.
