Date: Sun, 23 Jul 2006 13:08:00 +0300 From: Giorgos Keramidas <keramida@ceid.upatras.gr> To: "R. Tyler Ballance" <tyler@bleepsoft.com> Cc: freebsd-hackers@freebsd.org Subject: Re: Machine-dependent code extension? Message-ID: <20060723100800.GC24435@gothmog.pc> In-Reply-To: <A69D645F-5DBC-48B3-BEC4-013EED427C0C@bleepsoft.com> References: <A69D645F-5DBC-48B3-BEC4-013EED427C0C@bleepsoft.com>
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On 2006-07-22 20:51, "R. Tyler Ballance" <tyler@bleepsoft.com> wrote:
> I'm just wondering, the machine-dependent assembly tied into the i386
> kernel, that's all named ${FILENAME}., while in the arm/ kernel
> machine-dependent code is named ${FILENAME}.S, what's the difference?
> Or is there none, just a change in convention?
It looks like you missed a ".s" extension in the i386 case above, right?
If this is what you are asking, then the difference between *.s and *.S
is that the latter is preprocessed by cpp(1). The GNU as(1) manual
hints at this difference here:
File: as.info, Node: Preprocessing, Next: Whitespace, Up: Syntax
3.1 Preprocessing
=================
The `as' internal preprocessor:
* adjusts and removes extra whitespace. It leaves one space or tab
before the keywords on a line, and turns any other whitespace on
the line into a single space.
* removes all comments, replacing them with a single space, or an
appropriate number of newlines.
* converts character constants into the appropriate numeric values.
It does not do macro processing, include file handling, or anything
else you may get from your C compiler's preprocessor. You can do
include file processing with the `.include' directive (*note `.include':
! Include.). You can use the GNU C compiler driver to get other "CPP"
! style preprocessing by giving the input file a `.S' suffix. *Note
! Options Controlling the Kind of Output: (gcc.info)Overall Options.
Excess whitespace, comments, and character constants cannot be used
in the portions of the input text that are not preprocessed.
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