+++ /dev/null
-1998-08-11
-
-This directory contains the egcs variant of version 0.5.24 of the
-GNU Fortran compiler (g77). The GNU Fortran compiler is free software.
-See the file COPYING.g77 for copying permission.
-
-Currently, two variants of g77 exist. One is the Free Software Foundation
-(FSF) variant. The other is the egcs variant. As of egcs version 1.1,
-these variants are kept fairly similar in most respects. Pertinent
-differences, such as the layout of the source code, are specified below.
-
-Below, `[FSF]' denotes information applicable to only the FSF variant of
-g77, while `[egcs]' denotes egcs-only information.
-
-
-* IMPORTANT: Things you *must* do (or avoid) are marked with a * at the
- beginning of the line in this file!!!
-
-
-The email address to which bugs are to be reported is either
-[FSF] <fortran@gnu.org> or [egcs] <egcs-bugs@egcs.cygnus.com>.
-
-* *DO NOT* send any email (reporting bugs, asking questions, etc.) to
- either of these addresses without *first* reading the g77 documentation.
- Use `info', Info mode in GNU Emacs, or a text viewer such as `more' to
- do this.
-
- The g77 documentation is in the source files named `g77.info',
- `g77.info-1', `g77.info-2', and so on in the `f' subdirectory. If these
- files are not present or you can't find them, contact the person or
- organization that put together the g77 distribution you are using (probably
- not the FSF or egcs), or ask your system administrator for help.
-
-
-This README applies to only the g77-specific portions of the source-code
-tree that contains it. These portions include:
-
- - The README.g77 and [FSF] COPYING.g77 files, in this directory, "this
- directory" being [FSF] the top-level directory containing a g77
- distribution or [egcs] the gcc/ subdirectory of an egcs distribution.
-
- - The g77 front end, in the f/ subdirectory of this directory.
-
- - The libg2c library, in [FSF] the f/runtime/ subdirectory of this
- directory or [egcs] the libf2c/ directory under the top-level
- directory of the egcs distribution.
-
-
-* To build g77, you must have a source distribution of [FSF] gcc
- version 2.8 or [egcs] egcs version 1.1. Do not attempt to use
- any other version of gcc or egcs, because this version of g77 is
- designed to work with only those versions.
-
- Note that you must have *source* copies of the gcc or egcs distribution!
- You cannot build g77 just using binaries of gcc or egcs. Also, unless
- you are an expert, avoid using any distribution of gcc or egcs not
- identical to the ones distributed by the FSF and Cygnus Support,
- respectively. The primary FSF distribution site is:
-
- <ftp://ftp.gnu.org/pub/gnu/>
-
- The primary egcs distribution site is:
-
- <ftp://ftp.cygnus.com/pub/egcs/>
-
- Both of these sites have approved mirror sites from which valid
- distributions also may be obtained.
-
-* Do not attempt to combine the egcs version of g77 with the FSF
- gcc distribution, or the FSF version of g77 with the egcs gcc
- distribution. Although the differences are minor, they might
- be sufficient to prevent g77 from building properly, or from
- working properly if the build appears to succeed.
-
-[FSF] g77 is distributed as g77-<version>/f/ so that unpacking the g77
-distribution is done in the normal GNU way, resulting in a directory having
-the version number in the name. However, to build g77, the g77 distribution
-must be merged with an appropriate gcc distribution, normally in a gcc
-source directory, before configuring, building, and installing g77.
-
-[FSF] If you have just unpacked the g77 distribution, before proceeding,
-you must merge the contents of the g77 distribution with the appropriate
-gcc distribution on your system.
-
-* [FSF] Read and follow the instructions in f/INSTALL that
- explain how to merge a g77 source directory into a gcc source
- directory. You can use Info to read the same installation
- instructions via:
-
- info -f f/g77.info -n Unpacking
-
-[FSF] The resulting directory layout includes the following, where gcc/
-might be a link to, for example, gcc-2.8.1/:
-
- gcc/ Non-g77 files in gcc
- gcc/COPYING.g77 A copy of the GPL, under which g77 is licensed
- gcc/README.g77 This file
- gcc/f/ GNU Fortran front end
- gcc/f/runtime/ libg2c configuration and g2c.h file generation
- gcc/f/runtime/libF77/ Non-I/O portion of libg2c
- gcc/f/runtime/libI77/ I/O portion of libg2c
- gcc/f/runtime/libU77/ Additional interfaces to libc for libg2c
-
-[FSF] Applying g77 patches in the form of .diff files is done by typing
-`patch -p1 -d gcc' (where gcc/ contains the f/ subdirectory). That is,
-g77 patches are distributed in the same form, and at the same directory
-level, as patches to the gcc distribution. (Note: make sure you're
-using GNU patch, version 2.5 or later! Other versions of patch
-have trouble with g77-related patches.)
-
-[egcs] The egcs version of g77 is distributed already merged with
-the rest of egcs (such as the gcc back end).
-
-[egcs] The resulting directory layout includes the following, where egcs/
-might be a link to, for example, egcs-1.1/:
-
- egcs/gcc/ Non-g77 files in gcc
- egcs/gcc/README.g77 This file
- egcs/gcc/f/ GNU Fortran front end
- egcs/libf2c/ libg2c configuration and g2c.h file generation
- egcs/libf2c/libF77/ Non-I/O portion of libg2c
- egcs/libf2c/libI77/ I/O portion of libg2c
- egcs/libf2c/libU77/ Additional interfaces to libc for libg2c
-
-[egcs] Applying g77-specific patches to egcs is done the same way as
-applying other egcs patches.
-
-
-Below, `libf2c/' shall denote [FSF] gcc/f/runtime/ or [egcs] egcs/libf2c/,
-while `f/' shall denote [FSF] the rest of gcc/f/ or [egcs] egcs/gcc/f/.
-
-
-Components of note in g77 are described below.
-
-f/ as a whole contains the program GNU Fortran (g77), while libf2c/
-contains a portion of the separate program f2c. Note: The libf2c
-code is not part of the program g77, just distributed with it.
-
-f/ contains text files that document the Fortran compiler, source
-files for the GNU Fortran Front End (FFE), and some other stuff.
-The g77 compiler code is placed in f/ because it, along with its contents,
-is designed to be a subdirectory of a GNU CC (gcc) source directory, gcc/,
-which is structured so that language-specific front ends can be "dropped
-in" as subdirectories. The C++ front end (g++), is an example of this --
-it resides in the cp/ subdirectory. Note that the C front end (also
-referred to as gcc) is an exception to this, as its source files reside
-in the gcc/ directory itself.
-
-libf2c/ contains the run-time libraries for the f2c program, also used
-by g77. These libraries normally referred to collectively as libf2c.
-When built as part of g77, libf2c is installed under the name libg2c to avoid
-conflict with any existing version of libf2c, and thus is often referred
-to as libg2c when the g77 version is specifically being referred to.
-
-The netlib version of libf2c/ contains two distinct libraries, libF77 and
-libI77, each in their own subdirectories. In g77, this distinction is not
-made, beyond maintaining the subdirectory structure in the source-code tree.
-
-libf2c/ is not part of the program g77, just distributed with it. It
-contains files not present in the official (netlib) version of libf2c,
-and also contains some minor changes made from libf2c, to fix some bugs,
-and to facilitate automatic configuration, building, and installation of
-libf2c (as libg2c) for use by g77 users.
-
-* See libf2c/README for more information, including licensing conditions
- governing distribution of programs containing code from libg2c.
-
-libg2c, g77's version of libf2c, adds Dave Love's implementation of
-libU77, in the libf2c/libU77/ directory. This library is distributed
-under the GNU Library General Public License (LGPL) -- see the
-file libf2c/libU77/COPYING.LIB for more information, as this license
-governs distribution conditions for programs containing code from
-this portion of the library.
-
-
-Files of note in g77 are described below.
-
-f/BUGS lists some important bugs known to be in g77. Or:
-
- info -f f/g77.info -n "Actual Bugs"
-
-f/ChangeLog lists recent changes to g77 internals.
-
-libf2c/ChangeLog lists recent changes to libg2c internals.
-
-[FSF] f/INSTALL describes how to build and install GNU Fortran. Or:
-
- info -f f/g77.info -n Installation
-
-f/NEWS contains the per-release changes. These include the user-visible
-changes described under "Changes" in the g77 documentation, plus internal
-changes of import. Or:
-
- info -f f/g77.info -n News
-
-* All users of g77 (not just installers) should read f/g77.info*
- as well, using the `more' command if neither the `info' command,
- nor GNU Emacs (with its Info mode), are available, or if they
- aren't yet accustomed to using these tools. Read f/BUGS and f/NEWS
- plus, if you are planning on building or installing the FSF version
- of g77, f/INSTALL, at the very least! All of these files are
- readable as "plain text" files.
-
-* Also see <ftp://alpha.gnu.org/g77.plan> for up-to-date information
- regarding g77 bug reports, known bugs, bug-fixes, and new versions.
-
-
-The rest of this file is of note to only those who wish to
-debug, modify, or test the FFE (in conjunction with the gcc back end).
-
-If you want to explore the FFE code, which lives entirely in f/, here
-are a few clues. The file g77spec.c contains the g77-specific source code
-for the `g77' command only -- this just forms a variant of the `gcc'
-command, so, just as the `gcc' command itself does not contain
-the C front end, the `g77' command does not contain the Fortran front
-end (FFE). The FFE code ends up in an executable named `f771', which
-does the actual compiling, so it contains the FFE plus the gcc back end
-(the latter to do most of the optimization, and the code generation).
-
-The file parse.c is the source file for main() for a stand-alone FFE and
-yyparse() for f771. (Stand-alone building of the FFE doesn't work these days.)
-The file top.c contains the top-level FFE function ffe_file and it (along
-with top.h) define all ffe_[a-z].*, ffe[A-Z].*, and FFE_[A-Za-z].* symbols.
-The file fini.c is a main() program that is used when building the FFE to
-generate C header and source files for recognizing keywords. The files
-malloc.c and malloc.h comprise a memory manager that defines all
-malloc_[a-z].*, malloc[A-Z].*, and MALLOC_[A-Za-z].* symbols. All other
-modules named <xyz> are comprised of all files named <xyz>*.<ext> and
-define all ffe<xyz>_[a-z].*, ffe<xyz>[A-Z].*, and FFE<XYZ>_[A-Za-z].* symbols.
-If you understand all this, congratulations -- it's easier for me to remember
-how it works than to type in these grep patterns (such as they are). But it
-does make it easy to find where a symbol is defined -- for example,
-the symbol "ffexyz_set_something" would be defined in xyz.h and implemented
-there (if it's a macro) or in xyz.c.
-
-The "porting" files of note currently are: proj.h, which defines the
-"language" used by all the other source files (the language being
-Standard C plus some useful things like ARRAY_SIZE and such) -- change
-this file when you find your system doesn't properly define a Standard C
-macro or function, for example; target.h and target.c, which describe
-the target machine in terms of what data types are supported, how they are
-denoted (what C type does an INTEGER*8 map to, for example), how to convert
-between them, and so on (though as of 0.5.3, more and more of this information
-is being dynamically configured by ffecom_init_0); com.h and com.c, which
-interface to the target back end (currently only FFE stand-alone and the GBE);
-ste.c, which contains code for implementing recognized executable statements
-in the target back end (again currently either FFE or GBE); src.h and src.c,
-which describe information on the format(s) of source files (such as whether
-they are never to be processed as case-insensitive with regard to Fortran
-keywords); and proj.c, which contains whatever code is needed to support
-the language defined by proj.h.
-
-If you want to debug the f771 executable, for example if it crashes,
-note that the global variables "lineno" and "input_filename" are set
-to reflect the current line being read by the lexer during the first-pass
-analysis of a program unit and to reflect the current line being
-processed during the second-pass compilation of a program unit. If
-an invocation of the function ffestd_exec_end() is on the stack,
-the compiler is in the second pass, otherwise it is in the first.
-(This information might help you reduce a test case and/or work around
-a bug in g77 until a fix is available.)
-
-Any questions or comments on these topics? Read the g77 documentation!
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