NAME¶
ndisasm - the Netwide Disassembler, an 80x86 binary file
disassembler
SYNOPSIS¶
ndisasm [ -o origin ] [ -s sync-point [...]]
[ -a | -i ] [ -b bits ] [ -u ] [ -e
hdrlen ] [ -p vendor ] [ -k offset,length [...]] infile
DESCRIPTION¶
The ndisasm command generates a disassembly listing of the
binary file infile and directs it to stdout.
OPTIONS¶
-h
Causes ndisasm to exit immediately, after giving a
summary of its invocation options.
-r|-v
Causes ndisasm to exit immediately, after
displaying its version number.
-o origin
Specifies the notional load address for the file. This
option causes ndisasm to get the addresses it lists down the left hand
margin, and the target addresses of PC-relative jumps and calls, right.
-s sync-point
Manually specifies a synchronisation address, such that
ndisasm will not output any machine instruction which encompasses bytes
on both sides of the address. Hence the instruction which starts at that
address will be correctly disassembled.
-e hdrlen
Specifies a number of bytes to discard from the beginning
of the file before starting disassembly. This does not count towards the
calculation of the disassembly offset: the first disassembled
instruction will be shown starting at the given load address.
-k offset,length
Specifies that length bytes, starting from
disassembly offset offset, should be skipped over without generating
any output. The skipped bytes still count towards the calculation of the
disassembly offset.
-a|-i
Enables automatic (or intelligent) sync mode, in which
ndisasm will attempt to guess where synchronisation should be
performed, by means of examining the target addresses of the relative jumps
and calls it disassembles.
-b bits
Specifies 16-, 32- or 64-bit mode. The default is 16-bit
mode.
-u
Specifies 32-bit mode, more compactly than using
‘-b 32’.
-p vendor
Prefers instructions as defined by vendor in case
of a conflict. Known vendor names include intel, amd,
cyrix, and idt. The default is intel.
RESTRICTIONS¶
ndisasm only disassembles binary files: it has no
understanding of the header information present in object or executable
files. If you want to disassemble an object file, you should probably be
using objdump(1).
Auto-sync mode won’t necessarily cure all your
synchronisation problems: a sync marker can only be placed automatically if
a jump or call instruction is found to refer to it before
ndisasm actually disassembles that part of the code. Also, if
spurious jumps or calls result from disassembling non-machine-code data,
sync markers may get placed in strange places. Feel free to turn auto-sync
off and go back to doing it manually if necessary.