Commit 7001ee2d by Craig Burley Committed by Craig Burley

Dave Love's Intel-related doc fixes

From-SVN: r27375
parent db1421c7
Sat Jun 5 17:04:16 1999 Craig Burley <craig@jcb-sc.com>
From Dave Love to egcs-patches on 20 May 1999 17:38:38 +0100:
* invoke.texi: Clarify text vis-a-vis Intel CPUs.
Sat Jun 5 12:11:24 1999 Mark Mitchell <mark@codesourcery.com> Sat Jun 5 12:11:24 1999 Mark Mitchell <mark@codesourcery.com>
* mips.h (mips_output_conditional_branch): New function. * mips.h (mips_output_conditional_branch): New function.
......
Sat Jun 5 17:03:23 1999 Craig Burley <craig@jcb-sc.com>
From Dave Love to egcs-patches on 20 May 1999 17:38:38 +0100:
* g77.texi: Clean up fossil text vis-a-vis Intel CPUs.
Fri Jun 4 13:56:56 1999 Craig Burley <craig@jcb-sc.com> Fri Jun 4 13:56:56 1999 Craig Burley <craig@jcb-sc.com>
* Make-lang.in: Use libsubdir, not prefix, to store * Make-lang.in: Use libsubdir, not prefix, to store
......
...@@ -10774,30 +10774,25 @@ compiler, typically @code{gcc}.) ...@@ -10774,30 +10774,25 @@ compiler, typically @code{gcc}.)
@node Use Submodel Options @node Use Submodel Options
@subsection Use Submodel Options @subsection Use Submodel Options
@cindex Pentium optimizations
@cindex optimization, for Pentium
@cindex 586/686 CPUs
@cindex submodels @cindex submodels
Using an appropriate @samp{-m} option to generate specific code for your Using an appropriate @samp{-m} option to generate specific code for your
CPU may be worthwhile, though it may mean the executable won't run on CPU may be worthwhile, though it may mean the executable won't run on
other versions of the CPU that don't support the same instruction set. other versions of the CPU that don't support the same instruction set.
@xref{Submodel Options,,Hardware Models and Configurations,gcc,Using and @xref{Submodel Options,,Hardware Models and Configurations,gcc,Using and
Porting GNU CC}. Porting GNU CC}. For instance on an x86 system the compiler might have
been built---as shown by @samp{g77 -v}---for the target
For recent CPUs that don't have explicit support in @samp{i386-pc-linux-gnu}, i.e.@: an @samp{i386} CPU@. In that case to
the released version of @code{gcc}, it may still be possible to get generate code best optimized for a Pentium you could use the option
improvements. @samp{-march=pentium}.
For instance, the flags recommended for 586/686
(Pentium(Pro)) chips for building the Linux kernel are: For recent CPUs that don't have explicit support in the released version
of @code{gcc}, it @emph{might} still be possible to get improvements
@smallexample with certain @samp{-m} options.
-m486 -malign-loops=2 -malign-jumps=2 -malign-functions=2
-fomit-frame-pointer @samp{-fomit-frame-pointer} can help performance on x86 systems and
@end smallexample others. It will, however, inhibit debugging on the systems on which it
is not turned on anyway by @samp{-O}.
@noindent @samp{-fomit-frame-pointer} will, however, inhibit debugging
on x86 systems.
@node Trouble @node Trouble
@chapter Known Causes of Trouble with GNU Fortran @chapter Known Causes of Trouble with GNU Fortran
......
...@@ -5044,7 +5044,9 @@ instructions. The choices for @var{cpu type} are: ...@@ -5044,7 +5044,9 @@ instructions. The choices for @var{cpu type} are:
While picking a specific @var{cpu type} will schedule things appropriately While picking a specific @var{cpu type} will schedule things appropriately
for that particular chip, the compiler will not generate any code that for that particular chip, the compiler will not generate any code that
does not run on the i386 without the @samp{-march=@var{cpu type}} option does not run on the i386 without the @samp{-march=@var{cpu type}} option
being used. being used. @samp{i586} is equivalent to @samp{pentium} and @samp{i686}
is equivalent to @samp{pentiumpro}. @samp{k6} is the AMD chip as
opposed to the Intel ones.
@item -march=@var{cpu type} @item -march=@var{cpu type}
Generate instructions for the machine type @var{cpu type}. The choices Generate instructions for the machine type @var{cpu type}. The choices
...@@ -5056,7 +5058,7 @@ specifying @samp{-march=@var{cpu type}} implies @samp{-mcpu=@var{cpu type}}. ...@@ -5056,7 +5058,7 @@ specifying @samp{-march=@var{cpu type}} implies @samp{-mcpu=@var{cpu type}}.
@itemx -mpentium @itemx -mpentium
@itemx -mpentiumpro @itemx -mpentiumpro
Synonyms for -mcpu=i386, -mcpu=i486, -mcpu=pentium, and -mcpu=pentiumpro Synonyms for -mcpu=i386, -mcpu=i486, -mcpu=pentium, and -mcpu=pentiumpro
respectively. These synonyms are depricated. respectively. These synonyms are deprecated.
@item -mieee-fp @item -mieee-fp
@itemx -mno-ieee-fp @itemx -mno-ieee-fp
......
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