Subversion Repositories openrisc_2011-10-31

                README for GAS

A number of things have changed since version 1 and the wonderful

world of gas looks very different.  There's still a lot of irrelevant

garbage lying around that will be cleaned up in time.  Documentation

is scarce, as are logs of the changes made since the last gas release.

My apologies, and I'll try to get something useful.

Unpacking and Installation - Summary

====================================

See ../binutils/README.

To build just the assembler, make the target all-gas.

Documentation

=============

The GAS release includes texinfo source for its manual, which can be processed

into `info' or `dvi' forms.

The DVI form is suitable for printing or displaying; the commands for doing

this vary from system to system.  On many systems, `lpr -d' will print a DVI

file.  On others, you may need to run a program such as `dvips' to convert the

DVI file into a form your system can print.

If you wish to build the DVI file, you will need to have TeX installed on your

system.  You can rebuild it by typing:

        cd gas/doc

        make as.dvi

The Info form is viewable with the GNU Emacs `info' subsystem, or the

stand-alone `info' program, available as part of the GNU Texinfo distribution.

To build the info files, you will need the `makeinfo' program.  Type:

        cd gas/doc

        make info

Specifying names for hosts and targets

======================================

   The specifications used for hosts and targets in the `configure'

script are based on a three-part naming scheme, but some short

predefined aliases are also supported.  The full naming scheme encodes

three pieces of information in the following pattern:

     ARCHITECTURE-VENDOR-OS

   For example, you can use the alias `sun4' as a HOST argument or in a

`--target=TARGET' option.  The equivalent full name is

`sparc-sun-sunos4'.

   The `configure' script accompanying GAS does not provide any query

facility to list all supported host and target names or aliases.

`configure' calls the Bourne shell script `config.sub' to map

abbreviations to full names; you can read the script, if you wish, or

you can use it to test your guesses on abbreviations--for example:

     % sh config.sub i386v

     i386-unknown-sysv

     % sh config.sub i786v

     Invalid configuration `i786v': machine `i786v' not recognized

`configure' options

===================

   Here is a summary of the `configure' options and arguments that are

most often useful for building GAS.  `configure' also has several other

options not listed here.

     configure [--help]

               [--prefix=DIR]

               [--srcdir=PATH]

               [--host=HOST]

               [--target=TARGET]

               [--with-OPTION]

               [--enable-OPTION]

You may introduce options with a single `-' rather than `--' if you

prefer; but you may abbreviate option names if you use `--'.

`--help'

     Print a summary of the options to `configure', and exit.

`-prefix=DIR'

     Configure the source to install programs and files under directory

     `DIR'.

`--srcdir=PATH'

     Look for the package's source code in directory DIR.  Usually

     `configure' can determine that directory automatically.

`--host=HOST'

     Configure GAS to run on the specified HOST.  Normally the

     configure script can figure this out automatically.

     There is no convenient way to generate a list of all available

     hosts.

`--target=TARGET'

     Configure GAS for cross-assembling programs for the specified

     TARGET.  Without this option, GAS is configured to assemble .o files

     that run on the same machine (HOST) as GAS itself.

     There is no convenient way to generate a list of all available

     targets.

`--enable-OPTION'

     These flags tell the program or library being configured to

     configure itself differently from the default for the specified

     host/target combination.  See below for a list of `--enable'

     options recognized in the gas distribution.

`configure' accepts other options, for compatibility with configuring

other GNU tools recursively; but these are the only options that affect

GAS or its supporting libraries.

The `--enable' options recognized by software in the gas distribution are:

`--enable-targets=...'

     This causes one or more specified configurations to be added to those for

     which BFD support is compiled.  Currently gas cannot use any format other

     than its compiled-in default, so this option is not very useful.

`--enable-bfd-assembler'

     This causes the assembler to use the new code being merged into it to use

     BFD data structures internally, and use BFD for writing object files.

     For most targets, this isn't supported yet.  For most targets where it has

     been done, it's already the default.  So generally you won't need to use

     this option.

Compiler Support Hacks

======================

On a few targets, the assembler has been modified to support a feature

that is potentially useful when assembling compiler output, but which

may confuse assembly language programmers.  If assembler encounters a

.word pseudo-op of the form symbol1-symbol2 (the difference of two

symbols), and the difference of those two symbols will not fit in 16

bits, the assembler will create a branch around a long jump to

symbol1, and insert this into the output directly before the next

label: The .word will (instead of containing garbage, or giving an

error message) contain (the address of the long jump)-symbol2.  This

allows the assembler to assemble jump tables that jump to locations

very far away into code that works properly.  If the next label is

more than 32K away from the .word, you lose (silently); RMS claims

this will never happen.  If the -K option is given, you will get a

warning message when this happens.

REPORTING BUGS IN GAS

=====================

Bugs in gas should be reported to:

   bug-binutils@gnu.org.

They may be cross-posted to gcc-bugs@gnu.org if they affect the use of

gas with gcc.  They should not be reported just to gcc-bugs, since not

all of the maintainers read that list.

See ../binutils/README for what we need in a bug report.