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Diffstat (limited to 'manual')
| -rw-r--r-- | manual/install.texi | 20 |
1 files changed, 12 insertions, 8 deletions
diff --git a/manual/install.texi b/manual/install.texi index 1c516aa298..72e27a40ad 100644 --- a/manual/install.texi +++ b/manual/install.texi @@ -169,9 +169,10 @@ compile but use what you say instead of guessing what your system is. This is most useful to change the CPU submodel. For example, if configure guesses your machine as @code{i586-pc-linux-gnu} but you want to compile a library optimized for 386es, give -@samp{--host=i386-pc-linux-gnu} or just @samp{--host=i386-linux}. (A -library compiled for a Pentium (@code{i586}) will still work on a 386, -but it may be slower.) +@samp{--host=i386-pc-linux-gnu} or just @samp{--host=i386-linux} and add +the appropriate compiler flags (@samp{-mcpu=i386} will do the trick) to +@var{CFLAGS}. (A library compiled for a Pentium (@code{i586}) will still +work on a 386, but it may be slower.) If you give just @samp{--build}, configure will get confused. @end table @@ -419,11 +420,14 @@ maintainers by sending electronic mail to @email{bug-glibc@@gnu.org}. Each case of @samp{i@var{x}86} can be @samp{i386}, @samp{i486}, @samp{i586}, or @samp{i686}. All of those configurations produce a -library that can run on any of these processors. The library will be -optimized for the specified processor, but will not use instructions not -available on all of them. If you want the library to use instructions -only available on newer processors, give GCC the appropriate @samp{-m} -switches via @var{CFLAGS}. +library that can run on any of these processors if the compiler is +configured correctly. The GCC compiler by default generates code +that's optimized for the machine it's configured for and will use the +instructions available on that machine. For example if your GCC is +configured for @samp{i686}, gcc will optimize for @samp{i686} and +might issue some @samp{i686} specific instructions. To generate code +for other models you should give GCC the appropriate @samp{-march=} +and @samp{-mcpu=} compiler switches via @var{CFLAGS}. @node Linux @appendixsec Specific advice for Linux systems |