gas/README

   1                 README for GAS
   2
   3 A number of things have changed since version 1 and the wonderful world of gas
   4 looks very different.  There's still a lot of irrelevant garbage lying around
   5 that will be cleaned up in time.  Documentation is scarce, as are logs of the
   6 changes made since the last gas release.  My apologies, and I'll try to get
   7 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 standalone `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 sun4
  61      sparc-sun-sunos411
  62      % sh config.sub sun3
  63      m68k-sun-sunos411
  64      % sh config.sub decstation
  65      mips-dec-ultrix42
  66      % sh config.sub hp300bsd
  67      m68k-hp-bsd
  68      % sh config.sub i386v
  69      i386-unknown-sysv
  70      % sh config.sub i786v
  71      Invalid configuration `i786v': machine `i786v' not recognized
  72
  73
  74 `configure' options
  75 ===================
  76
  77    Here is a summary of the `configure' options and arguments that are
  78 most often useful for building GAS.  `configure' also has several other
  79 options not listed here.
  80
  81      configure [--help]
  82                [--prefix=DIR]
  83                [--srcdir=PATH]
  84                [--host=HOST]
  85                [--target=TARGET]
  86                [--with-OPTION]
  87                [--enable-OPTION]
  88
  89 You may introduce options with a single `-' rather than `--' if you
  90 prefer; but you may abbreviate option names if you use `--'.
  91
  92 `--help'
  93      Print a summary of the options to `configure', and exit.
  94
  95 `-prefix=DIR'
  96      Configure the source to install programs and files under directory
  97      `DIR'.
  98
  99 `--srcdir=PATH'
 100      Look for the package's source code in directory DIR.  Usually
 101      `configure' can determine that directory automatically.
 102
 103 `--host=HOST'
 104      Configure GAS to run on the specified HOST.  Normally the
 105      configure script can figure this out automatically.
 106
 107      There is no convenient way to generate a list of all available
 108      hosts.
 109
 110 `--target=TARGET'
 111      Configure GAS for cross-assembling programs for the specified
 112      TARGET.  Without this option, GAS is configured to assemble .o files
 113      that run on the same machine (HOST) as GAS itself.
 114
 115      There is no convenient way to generate a list of all available
 116      targets.
 117
 118 `--enable-OPTION'
 119      These flags tell the program or library being configured to
 120      configure itself differently from the default for the specified
 121      host/target combination.  See below for a list of `--enable'
 122      options recognized in the gas distribution.
 123
 124 `configure' accepts other options, for compatibility with configuring
 125 other GNU tools recursively; but these are the only options that affect
 126 GAS or its supporting libraries.
 127
 128 The `--enable' options recognized by software in the gas distribution are:
 129
 130 `--enable-targets=...'
 131      This causes one or more specified configurations to be added to those for
 132      which BFD support is compiled.  Currently gas cannot use any format other
 133      than its compiled-in default, so this option is not very useful.
 134
 135 `--enable-bfd-assembler'
 136      This causes the assembler to use the new code being merged into it to use
 137      BFD data structures internally, and use BFD for writing object files.
 138      For most targets, this isn't supported yet.  For most targets where it has
 139      been done, it's already the default.  So generally you won't need to use
 140      this option.
 141
 142 Supported platforms
 143 ===================
 144
 145 At this point I believe gas to be ansi only code for most target cpu's.  That
 146 is, there should be relatively few, if any host system dependencies.  So
 147 porting (as a cross-assembler) to hosts not yet supported should be fairly
 148 easy.  Porting to a new target shouldn't be too tough if it's a variant of one
 149 already supported.
 150
 151 Native assembling should work on:
 152
 153         sun3
 154         sun4
 155         386bsd
 156         bsd/386
 157         delta (m68k-sysv from Motorola)
 158         delta88 (m88k-sysv from Motorola)
 159         GNU/linux
 160         m68k hpux 8.0 (hpux 7.0 may be a problem)
 161         vax bsd, ultrix, vms
 162         hp9000s300
 163         decstation
 164         irix 4
 165         irix 5
 166         miniframe (m68k-sysv from Convergent Technologies)
 167         i386-aix (ps/2)
 168         hppa (hpux 4.3bsd, osf1)
 169         AIX
 170         unixware
 171         sco 3.2v4.2
 172         sco openserver 5.0 (a.k.a. 3.2v5.0 )
 173         sparc solaris
 174         ns32k (netbsd, lites)
 175
 176 I believe that gas as a cross-assembler can currently be targetted for
 177 most of the above hosts, plus
 178
 179         decstation-bsd (a.out format, to be used in BSD 4.4)
 180         ebmon29k
 181         go32 (DOS on i386, with DJGPP -- old a.out version)
 182         h8/300, h8/500 (Hitachi)
 183         i386-aix (ps/2)
 184         i960-coff
 185         mips ecoff (decstation-ultrix, iris, mips magnum, mips-idt-ecoff)
 186         Mitsubishi d10v and d30v
 187         nindy960
 188         powerpc EABI
 189         SH (Hitachi)
 190         sco386
 191         TI tic30 and tic80
 192         vax bsd or ultrix?
 193         vms
 194         vxworks68k
 195         vxworks960
 196         z8000 (Zilog)
 197
 198 MIPS ECOFF support has been added, but GAS will not run a C-style
 199 preprocessor.  If you want that, rename your file to have a ".S" suffix, and
 200 run gcc on it.  Or run "gcc -xassembler-with-cpp foo.s".
 201
 202 Support for ELF should work now for sparc, hppa, i386, alpha, m68k,
 203 MIPS, powerpc.
 204
 205 Support for sequent (ns32k), tahoe, i860, m88k may be suffering from bitrot.
 206
 207 If you try out gas on some host or target not listed above, please let me know
 208 the results, so I can update the list.
 209
 210 Compiler Support Hacks
 211 ======================
 212
 213 On a few targets, the assembler has been modified to support a feature
 214 that is potentially useful when assembling compiler output, but which
 215 may confuse assembly language programmers.  If assembler encounters a
 216 .word pseudo-op of the form symbol1-symbol2 (the difference of two
 217 symbols), and the difference of those two symbols will not fit in 16
 218 bits, the assembler will create a branch around a long jump to
 219 symbol1, and insert this into the output directly before the next
 220 label: The .word will (instead of containing garbage, or giving an
 221 error message) contain (the address of the long jump)-symbol2.  This
 222 allows the assembler to assemble jump tables that jump to locations
 223 very far away into code that works properly.  If the next label is
 224 more than 32K away from the .word, you lose (silently); RMS claims
 225 this will never happen.  If the -K option is given, you will get a
 226 warning message when this happens.
 227
 228
 229 REPORTING BUGS IN GAS
 230 =====================
 231
 232 Bugs in gas should be reported to bug-gnu-utils@gnu.org.  They may be
 233 cross-posted to bug-gcc if they affect the use of gas with gcc.  They
 234 should not be reported just to bug-gcc, since I don't read that list,
 235 and therefore wouldn't see them.
 236
 237 If you report a bug in GAS, please remember to include:
 238
 239 A description of exactly what went wrong, and exactly what should have
 240 happened instead.
 241
 242 The type of machine (VAX, 68020, etc) and operating system (BSD, SunOS, DYNIX,
 243 VMS, etc) GAS was running on.
 244
 245 The configuration name(s) given to the "configure" script.  The
 246 "config.status" file should have this information.
 247
 248 The options given to GAS at run time.
 249
 250 The actual input file that caused the problem.
 251
 252 It is silly to report a bug in GAS without including an input file for GAS.
 253 Don't ask us to generate the file just because you made it from files you
 254 think we have access to.
 255
 256 1. You might be mistaken.
 257 2. It might take us a lot of time to install things to regenerate that file.
 258 3. We might get a different file from the one you got, and might not see any
 259    bug.
 260
 261 To save us these delays and uncertainties, always send the input file for the
 262 program that failed.  A smaller test case that demonstrates the problem is of
 263 course preferable, but be sure it is a complete input file, and that it really
 264 does demonstrate the problem; but if paring it down would cause large delays
 265 in filing the bug report, don't bother.
 266
 267 If the input file is very large, and you are on the internet, you may want to
 268 make it avaliable for anonymous FTP instead of mailing it.  If you do, include
 269 instructions for FTP'ing it in your bug report.
 270
 271 If you expect to be contributing a large number of test cases, it would be
 272 helpful if you would look at the test suite included in the release (based on
 273 the Deja Gnu testing framework, available from the usual ftp sites) and write
 274 test cases to fit into that framework.  This is certainly not required.