ld86(1) ld86(1)
NAME
ld86 - Linker for as86(1)
SYNOPSIS
ld86 [-03MNdimrstyz[-]] [-llib_extension] [-o outfile] [-Ccrtfile]
[-Llibdir] [-Olibfile] [-Ttextaddr] [-Hheapsize] [-Ddataaddr] infile...
DESCRIPTION
This linker understands only the object files produced by the as86
assembler, it can link them into either an impure or a separate I&D
executable.
The linking defaults are everything off or none except for -0 and the
output file is a.out. There is not a standard library location defined
in the linker.
OPTIONS
-0 produce header with 16-bit magic
-3 produce header with 32-bit magic
-d delete the header from the output file, used for MSDOS COM
files. As a side effect this also includes -s as there’s nowhere
to put a symbol table.
-Cx add file libdir-from-search/crtx.o to list of files linked
-D data base address follows (in format suitable for strtoul)
-H the top of heap (initial stack) address (in format suitable for
strtoul)
-Lx add dir name x to the head of the list of library dirs searched
-M print symbols linked on stdout
-N Create a native Linux OMAGIC output file. If the contents are
i386 code the binary can be either linked by GCC or executed by
linux. If the -z option is also included the linker can generate
a QMAGIC executable.
-Ox add library or object file libdir-from-search/x to list of files
linked
-T text base address follows (in format suitable for strtoul)
-i separate I&D output
-lx add library libdir-from-search/libx.a to list of files linked
-m print modules linked on stdout
-o output file name follows
-s strip symbols
-r Generate a relocatable object from one source object, if the
linker is given the -N option also the output format will be the
hosts native format if possible.
-t trace modules being looked at on stdout
-y Alter the symbol tables to add label ’extensions’ so that labels
with more than 8 characters can be stored in elks executables.
-z produce "unmapped zero page" or "QMAGIC" executables
All the options not taking an argument may be turned off by following
the option letter by a ’-’, as for cc1.
PREDEFINED LABELS
The linker predefines several labels that can be imported into user
programs.
__etext
Standard C variable for the end of the text segment.
__edata
Standard C variable for the end of the initilised data.
__end Standard C variable for the end of the bss area.
__segoff
The offset within the executable file between the start of the
text segment and the start of the data segment in 16 byte
’paragraphs’. Note this is zero for impure (tiny model)
executables and is adjusted for executables that don’t start at
offset 0 within the segment.
__segXDL
The lowest address with data in segment ’X’. (eg __seg0DL is for
segment zero or the text segment, __seg3DL is for the data
segment) The value ’X’ is a hex digit.
__segXDH
The top of segment ’X’s data area.
__segXCL
The bottom of segment ’X’s ’common data’ or unitilised data
area. Each segment has both an initilised and unitilised data
area.
__segXCH
The top of segment ’X’s common area.
__segXSO
This is the adjusted offset from segment 0 of the start of
segment ’X’ in ’paragraphs’.
HISTORY
The 6809 version does not support -i.
The previous versions of the linker could produce an 8086 executable
with segments of a size >64k, now only i386 executables may have
segments this large.
BUGS
The linker cannot deal with reverse seeks caused by org instructions in
the object file. Unlike previous versions the current one traps the
error rather than trying to fill up the hard disk.
The linker produces a broken a.out object file if given one input and
the -r option this is so it is compatible with pre-dev86 versions.
Apr, 1997 ld86(1)
