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 (a] gnu.org. 159 160 They may be cross-posted to gcc-bugs (a] 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. 165 167 Copyright (C) 2012-2014 Free Software Foundation, Inc. 168 169 Copying and distribution of this file, with or without modification, 170 are permitted in any medium without royalty provided the copyright 171 notice and this notice are preserved. 172
