term% cat index.txt 2L(1) General Commands Manual 2L(1)
NAME
2l, 6l, 8l, kl, vl, xl - loaders
SYNOPSIS
2l [ option ... ] [ file ... ]
6l [ option ... ] [ file ... ]
8l [ option ... ] [ file ... ]
kl [ option ... ] [ file ... ]
vl [ option ... ] [ file ... ]
xl [ option ... ] [ file ... ]
DESCRIPTION
2l, 6l, 8l, kl, vl, and xl load the named files into MC68020, i960,
i386, SPARC, MIPS, and ATT3210 executable files. The files should be
object files or libraries (archives of object files) for the appropri‐
ate architecture. Also, a name like -lext represents the library
libext.a in /$objtype/lib, where objtype is one of 68020, 960, 386,
sparc, mips, or 3210. The libraries must have tables of contents (see
ar(1)).
In practice, -l options are rarely necessary as the header files for
the libraries cause their archives to be included automatically in the
load (see 2c(1)). For example, any program that includes header file
libc.h causes the loader to search the C library /$objtype/lib/libc.a.
Also, the loader creates an undefined symbol _main (or _mainp if pro‐
filing is enabled) to force loading of the startup linkage from the C
library.
The order of search to resolve undefined symbols is to load all files
and libraries mentioned explicitly on the command line, and then to re‐
solve remaining symbols by searching in topological order libraries
mentioned in header files included by files already loaded. When scan‐
ning such libraries, the algorithm is to scan each library repeatedly
until no new undefined symbols are picked up, then to start on the next
library. Thus if library A needs B which needs A again, it may be nec‐
essary to mention A explicitly so it will be read a second time.
The loader options are:
-l (As a bare option.) Suppress the default loading of the
startup linkage and libraries specified by header files.
-o out Place output in file out. Default is O.out, where O is the
first letter of the loader name.
-p Insert profiling code into the executable output; no special
action is needed during compilation or assembly.
-s Strip the symbol tables from the output file.
-a Print the object code in assembly language, with addresses.
-v Print debugging output that annotates the activities of the
load.
-cfunction
(Xl only) Place the function in the internal RAM of the
DSP3210.
-M (Kl only) Generate instructions rather than calls to emula‐
tion routines for multiply and divide.
-msize (Xl only) Use size (default 0, maximum 8192) bytes of inter‐
nal RAM of the DSP3210 for functions and small data items.
-Esymbol The entry point for the binary is symbol (default _main;
_mainp under -p).
-Hn Executable header is type n. The meaning of the types is ar‐
chitecture-dependent; typically type 1 is Plan 9 boot format
and type 2 is the regular Plan 9 format, the default. These
are reversed on the MIPS. The Next boot format is 3. Type 4
in vl creates a MIPS executable for an SGI Unix system.
-Tt The text segment starts at address t.
-Dd The data segment starts at address d.
-Rr The text segment is rounded to a multiple of r (if r is non‐
zero).
The numbers in the above options can begin with or to change the de‐
fault base from decimal to hexadecimal or octal. The defaults for the
values depend on the compiler and the header type.
The loaded image has several symbols inserted by the loader: etext is
the address of the end of the text segment; bdata is the address of the
beginning of the data segment; edata is the address of the end of the
data segment; and end is the address of the end of the bss segment, and
of the program.
FILES
/$objtype/lib
for -llib arguments.
SOURCE
/sys/src/cmd/2l etc.
SEE ALSO
2c(1), 2a(1), alef(1), ar(1), nm(1), db(1), prof(1)
Rob Pike, ``How to Use the Plan 9 C Compiler''
2L(1)