1:                 README for GAS
    2: 
    3: A number of things have changed since version 1 and the wonderful
    4: world of gas looks very different.  There's still a lot of irrelevant
    5: garbage lying around that will be cleaned up in time.  Documentation
    6: is scarce, as are logs of the changes made since the last gas release.
    7: My apologies, and I'll try to get something useful.
    8: 
    9: Unpacking and Installation - Summary
   10: ====================================
   11: 
   12: See ../binutils/README.
   13: 
   14: To build just the assembler, make the target all-gas.
   15: 
   16: Documentation
   17: =============
   18: 
   19: The GAS release includes texinfo source for its manual, which can be processed
   20: into `info' or `dvi' forms.
   21: 
   22: The DVI form is suitable for printing or displaying; the commands for doing
   23: this vary from system to system.  On many systems, `lpr -d' will print a DVI
   24: file.  On others, you may need to run a program such as `dvips' to convert the
   25: DVI file into a form your system can print.
   26: 
   27: If you wish to build the DVI file, you will need to have TeX installed on your
   28: system.  You can rebuild it by typing:
   29: 
   30:         cd gas/doc
   31:         make as.dvi
   32: 
   33: The Info form is viewable with the GNU Emacs `info' subsystem, or the
   34: stand-alone `info' program, available as part of the GNU Texinfo distribution.
   35: To build the info files, you will need the `makeinfo' program.  Type:
   36: 
   37:         cd gas/doc
   38:         make info
   39: 
   40: Specifying names for hosts and targets
   41: ======================================
   42: 
   43:    The specifications used for hosts and targets in the `configure'
   44: script are based on a three-part naming scheme, but some short
   45: predefined aliases are also supported.  The full naming scheme encodes
   46: three pieces of information in the following pattern:
   47: 
   48:      ARCHITECTURE-VENDOR-OS
   49: 
   50:    For example, you can use the alias `sun4' as a HOST argument or in a
   51: `--target=TARGET' option.  The equivalent full name is
   52: `sparc-sun-sunos4'.
   53: 
   54:    The `configure' script accompanying GAS does not provide any query
   55: facility to list all supported host and target names or aliases. 
   56: `configure' calls the Bourne shell script `config.sub' to map
   57: abbreviations to full names; you can read the script, if you wish, or
   58: you can use it to test your guesses on abbreviations--for example:
   59: 
   60:      % sh config.sub i386v
   61:      i386-unknown-sysv
   62:      % sh config.sub i786v
   63:      Invalid configuration `i786v': machine `i786v' not recognized
   64: 
   65: 
   66: `configure' options
   67: ===================
   68: 
   69:    Here is a summary of the `configure' options and arguments that are
   70: most often useful for building GAS.  `configure' also has several other
   71: options not listed here.
   72: 
   73:      configure [--help]
   74:                [--prefix=DIR]
   75:                [--srcdir=PATH]
   76:                [--host=HOST]
   77:                [--target=TARGET]
   78:                [--with-OPTION]
   79:                [--enable-OPTION]
   80: 
   81: You may introduce options with a single `-' rather than `--' if you
   82: prefer; but you may abbreviate option names if you use `--'.
   83: 
   84: `--help'
   85:      Print a summary of the options to `configure', and exit.
   86: 
   87: `-prefix=DIR'
   88:      Configure the source to install programs and files under directory
   89:      `DIR'.
   90: 
   91: `--srcdir=PATH'
   92:      Look for the package's source code in directory DIR.  Usually
   93:      `configure' can determine that directory automatically.
   94: 
   95: `--host=HOST'
   96:      Configure GAS to run on the specified HOST.  Normally the
   97:      configure script can figure this out automatically.
   98: 
   99:      There is no convenient way to generate a list of all available
  100:      hosts.
  101: 
  102: `--target=TARGET'
  103:      Configure GAS for cross-assembling programs for the specified
  104:      TARGET.  Without this option, GAS is configured to assemble .o files
  105:      that run on the same machine (HOST) as GAS itself.
  106: 
  107:      There is no convenient way to generate a list of all available
  108:      targets.
  109: 
  110: `--enable-OPTION'
  111:      These flags tell the program or library being configured to 
  112:      configure itself differently from the default for the specified
  113:      host/target combination.  See below for a list of `--enable'
  114:      options recognized in the gas distribution.
  115: 
  116: `configure' accepts other options, for compatibility with configuring
  117: other GNU tools recursively; but these are the only options that affect
  118: GAS or its supporting libraries.
  119: 
  120: The `--enable' options recognized by software in the gas distribution are:
  121: 
  122: `--enable-targets=...'
  123:      This causes one or more specified configurations to be added to those for
  124:      which BFD support is compiled.  Currently gas cannot use any format other
  125:      than its compiled-in default, so this option is not very useful.
  126: 
  127: `--enable-bfd-assembler'
  128:      This causes the assembler to use the new code being merged into it to use
  129:      BFD data structures internally, and use BFD for writing object files.
  130:      For most targets, this isn't supported yet.  For most targets where it has
  131:      been done, it's already the default.  So generally you won't need to use
  132:      this option.
  133: 
  134: Compiler Support Hacks
  135: ======================
  136: 
  137: On a few targets, the assembler has been modified to support a feature
  138: that is potentially useful when assembling compiler output, but which
  139: may confuse assembly language programmers.  If assembler encounters a
  140: .word pseudo-op of the form symbol1-symbol2 (the difference of two
  141: symbols), and the difference of those two symbols will not fit in 16
  142: bits, the assembler will create a branch around a long jump to
  143: symbol1, and insert this into the output directly before the next
  144: label: The .word will (instead of containing garbage, or giving an
  145: error message) contain (the address of the long jump)-symbol2.  This
  146: allows the assembler to assemble jump tables that jump to locations
  147: very far away into code that works properly.  If the next label is
  148: more than 32K away from the .word, you lose (silently); RMS claims
  149: this will never happen.  If the -K option is given, you will get a
  150: warning message when this happens.
  151: 
  152: 
  153: REPORTING BUGS IN GAS
  154: =====================
  155: 
  156: Bugs in gas should be reported to:
  157: 
  158:    bug-binutils@gnu.org.
  159: 
  160: They may be cross-posted to gcc-bugs@gnu.org if they affect the use of
  161: gas with gcc.  They should not be reported just to gcc-bugs, since not
  162: all of the maintainers read that list.
  163: 
  164: See ../binutils/README for what we need in a bug report.