438 lines
13 KiB
Plaintext
438 lines
13 KiB
Plaintext
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cxmon, Version 3.2
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A command-line file manipulation tool and disassembler
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Copyright (C) 1997-2007 Christian Bauer, Marc Hellwig
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GNU binutils disassemblers Copyright (C) 1988, 89, 91, 93, 94, 95, 96, 97, 1998
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Free Software Foundation, Inc.
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License
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-------
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cxmon is available under the terms of the GNU General Public License. See the
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file "COPYING" that is included in the distribution for details.
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Overview
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--------
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cxmon is an interactive command-driven file manipulation tool that is
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inspired by the "Amiga Monitor" by Timo Rossi. It has commands and features
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similar to a machine code monitor/debugger, but it lacks any functions for
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running/tracing code. There are, however, built-in PowerPC, 680x0, 80x86,
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x86-64, 6502 and Z80 disassemblers and special support for disassembling
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MacOS code. By default, cxmon operates on a fixed-size (but adjustable)
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memory buffer with adresses starting at 0.
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Installation
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------------
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Please consult the file "INSTALL" for installation instructions.
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Usage
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-----
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cxmon can be started from the Shell or from the Tracker (BeOS), but command
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line history doesn't work when started from the Tracker.
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Options:
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-m enables symbolic MacOS A-Trap and low memory globals display in the
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680x0 disassembler
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-r makes cxmon operate in real (virtual) memory space instead of an
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allocated buffer
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If no additional command line arguments are given, cxmon enters interactive
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mode. Otherwise, all remaining arguments are interpreted and executed as cxmon
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commands.
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The default buffer size is 1MB.
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The cxmon command prompt looks like this:
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[00000000]->
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The number in brackets is the value of "." (the "current address", see the
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section on expressions). You can get a short command overview by entering
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"h".
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Commands that create a longer output can be interrupted with Ctrl-C.
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To quit cxmon, enter the command "x".
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Constants, variables and expressions
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------------------------------------
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The default number base is hexadecimal. Decimal numbers must be prefixed with
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"_". Hexadecimal numbers may also be prefixed with "$" for clarity. Numbers
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can also be entered as ASCII characters enclosed in single quotes (e.g. 'BAPP'
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is the same as $42415050). All numbers are 32-bit values (one word).
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With the "set" command, variables can be defined that hold 32-bit integer
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values. A variable is referred to by its name. Variable names may be arbitrary
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combinations of digits and letters (they may also start with a digit) that
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are not also valid hexadecimal numbers. Names are case-sensitive.
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cxmon accepts expressions in all places where you have to specify a number.
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The following operators are available and have the same meaning and
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precedence as in the C programming language:
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~ complement
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+ unary plus
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- unary minus
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* multiplication
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/ integer division
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% modulo
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+ addition
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- subtraction
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<< shift left
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>> shift right
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& bitwise AND
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^ bitwise exclusive OR
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| bitwise inclusive OR
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Parentheses may be used to change the evaluation order of sub-expressions.
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There are two special symbols that can be used in expressions:
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. represents the "current address" (the value of "." is also displayed in
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the command prompt). What exactly the current address is, depends on the
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command last executed. The display commands set "." to the address after
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the last address displayed, the "hunt" commands sets "." to the address
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of the first found occurence of the search string, etc.
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: is used by the "apply" ("y") command and holds the value of the byte/
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half-word/word at the current address.
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The "modify" (":"), "fill" ("f") and "hunt" ("h") commands require you to
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specify a byte string. Byte strings consist of an arbitrary number of byte
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values and ASCII strings separated by commas. Examples:
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"string"
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12,34,56,78,9a,bc,de,f0
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"this",0a,"is a string",0a,"with","newlines",_10
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The buffer
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----------
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Those cxmon commands that operate on "memory" operate on a buffer allocated
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by cxmon whose size is adjustable with the "@" command. The default buffer
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size is 1MB. The buffer is an array of bytes where each byte has a 32-bit
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integer address. Addresses start at 0 and are taken modulo the buffer size
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(i.e. for the default 1MB buffer, addresses 0 and 100000 refer to the same
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byte).
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The buffer is the working area of cxmon where you load files into, manipulate
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them, and write files back from. Arbitraty portions of the buffer may be used
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as scratch space.
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Commands
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--------
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The following commands are available in cxmon ('[]' marks a parameter than
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can be left out):
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x Quit cxmon
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quits cxmon and returns to the shell.
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h Show help text
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displays a short overview of commands.
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?? Show list of commands
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displays a short list of available commands.
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ver Show version
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shows the version number of cxmon.
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? expression Calculate expression
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displays the value of the given expression in hex, decimal, and ASCII
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characters. If the value is negative, it is displayed as a signed and unsigned
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number.
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@ [size] Reallocate buffer
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changes the size of the buffer to the given number of bytes while preserving
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the contents of the buffer. If the "size" argument is omitted, the current
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buffer size is displayed.
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i [start [end]] ASCII memory dump
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displays the buffer contents from address "start" to address "end" as ASCII
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characters. Entering "i" without arguments is equivalent to "i .". The value
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of "." is set to the address after the last address displayed.
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b [start [end]] Binary memory dump
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displays the buffer contents from address "start" to address "end" in a binary
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format. Entering "b" without arguments is equivalent to "b .". The value of
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"." is set to the address after the last address displayed.
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m [start [end]] Hex/ASCII memory dump
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displays the buffer contents from address "start" to address "end" as hex
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words and ASCII characters. Entering "m" without arguments is equivalent to
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"m .". The value of "." is set to the address after the last address displayed.
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d [start [end]] Disassemble PowerPC code
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disassembles the buffer contents from address "start" to address "end".
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Entering "d" without arguments is equivalent to "d .". The value of "." is
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set to the address after the last address displayed.
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d65 [start [end]] Disassemble 6502 code
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disassembles the buffer contents from address "start" to address "end".
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Entering "d65" without arguments is equivalent to "d65 .". The value of
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"." is set to the address after the last address displayed.
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d68 [start [end]] Disassemble 680x0 code
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disassembles the buffer contents from address "start" to address "end".
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Entering "d68" without arguments is equivalent to "d68 .". The value of
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"." is set to the address after the last address displayed.
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d80 [start [end]] Disassemble Z80 code
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disassembles the buffer contents from address "start" to address "end".
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Entering "d80" without arguments is equivalent to "d80 .". The value of
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"." is set to the address after the last address displayed.
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d86 [start [end]] Disassemble 80x86 (32-bit) code
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disassembles the buffer contents from address "start" to address "end".
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Entering "d86" without arguments is equivalent to "d86 .". The value of
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"." is set to the address after the last address displayed.
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d8086 [start [end]] Disassemble 80x86 (16-bit) code
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disassembles the buffer contents from address "start" to address "end".
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Entering "d8086" without arguments is equivalent to "d8086 .". The value
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of "." is set to the address after the last address displayed.
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d8664 [start [end]] Disassemble x86-64 code
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disassembles the buffer contents from address "start" to address "end".
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Entering "d8086" without arguments is equivalent to "d8086 .". The value
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of "." is set to the address after the last address displayed.
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: start string Modify memory
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puts the specified byte string at the address "start" into the buffer. The
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value of "." is set to the address after the last address modified.
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f start end string Fill memory
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fill the buffer in the range from "start" to (and including) "end" with the
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given byte string.
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y[b|h|w] start end expr Apply expression to memory
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works like the "fill" ("f") command, but it doesn't fill with a byte string
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but with the value of an expression that is re-evaluated for each buffer
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location to be filled. The command comes in three flavors: "y"/"yb" works on
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bytes (8-bit), "yh" on half-words (16-bit) and "yw" on words (32-bit). The
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value of "." is the current address to be modified, the value of ":" holds
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the contents of this address before modification.
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Examples:
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yw 0 fff :<<8 shifts all words in the address range 0..fff to the left
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by 8 bits (you can use this to convert bitmap data from
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ARGB to RGBA format, for example)
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y 0 1234 ~: inverts all bytes in the address range 0..1234
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yh 2 ff 20000/. creates a table of the fractional parts of the reciprocals
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of 1..7f
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t start end dest Transfer memory
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transfers the buffer contents from "start" to (and including) "end" to "dest".
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Source and destination may overlap.
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c start end dest Compare memory
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compares the buffer contents in the range from "start" to (and including)
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"end" with the contents at "dest". The addresses of all different bytes and
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the total number of differences (decimal) are printed.
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h start end string Search for byte string
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searches for the given byte string in the buffer starting at "start" up to
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(and including) "end". The addresses and the total number of occurrences are
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displayed. The value of "." is set to the address of the first occurrence.
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\ "command" Execute shell command
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executes the given shell command which must be enclosed in quotes.
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ls [args] List directory contents
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works as the shell command "ls".
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rm [args] Remove file(s)
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works as the shell command "rm".
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cp [args] Copy file(s)
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works as the shell command "cp".
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mv [args] Move file(s)
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works as the shell command "mv".
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cd directory Change current directory
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works as the shell command "cd". The name of the directory doesn't have to be
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enclosed in quotes.
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o ["file"] Redirect output
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When a file name is specified, all following output is redirected to this
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file. The file name must be enclosed in quotation marks even if it contains
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no spaces. Entering "o" without parameters closes the file and directs the
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output into the terminal window again.
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[ start "file" Load data from file
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loads the contents of the specified file into the buffer starting from address
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"start". The file name must be enclosed in quotation marks even if it contains
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no spaces. The value of "." is set to the address after the last address
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affected by the load.
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] start size "file" Save data to file
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writes "size" number of bytes of the buffer from "start" to the specified file.
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The file name must be enclosed in quotation marks even if it contains no spaces.
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set [var[=value]] Set/clear/show variables
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If no arguments are given, all currently defined variables are displayed.
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Otherwise, the value of "var" is set to the specified value. If "=value"
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is omitted, the variable "var" is cleared.
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cv Clear all variables
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clears all currently defined variables.
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Examples
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--------
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Here are some simple examples for what is possible with cxmon.
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Join "file1" and "file2" to "file3":
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[ 0 "file1"
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[ . "file2"
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] 0 . "file3"
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Remove the first 24 bytes (e.g. an unneeded header) of a file:
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[ 0 "file"
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] 18 .-18 "file"
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Load the cxmon executable and search for PowerPC "nop" commands:
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[ 0 "cxmon"
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h 0 . 60,00,00,00
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Create a modified version of cxmon so that the prompt has " $" instead of
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"->":
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[ 0 "cxmon"
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set size=.
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h 0 . "->"
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: . " $"
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] 0 size "cxmon1"
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Convert a binary file which contains 16-bit numbers in little-endian format
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to big-endian format (or vice-versa):
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[ 0 "file"
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yh 0 .-1 :>>8|:<<8
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] 0 . "file"
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Load a BeBox boot ROM image and start disassembling the system reset handler:
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[ 0 "bootnub.image"
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d 100
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Using cxmon in your own programs
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--------------------------------
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cxmon provides a simple interface for integration in other programs. It can,
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for example, be used as a monitor/debugger for an emulator (it is used in
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Basilisk II in this way).
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Here's how to do it (all functions are defined in the mon.h header file):
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1. Link all the cxmon object files, except main.o, to your program.
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2. In your program, call mon_init() before using any other cxmon functions.
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3. After calling mon_init(), set the mon_read_byte and mon_write_byte
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function pointers to the routines used for accessing memory.
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4. You can use mon_add_command() to add new commands to cxmon by specifying
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the command name, function and help text. From within your command
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function, you can use mon_get_token() and mon_expression() to parse the
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arguments and the mon_read/write_*() functions to access memory.
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5. To enter cxmon, call the mon() function like this:
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const char *args[3] = {"mon", "-r", NULL};
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mon(2, args);
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6. If you're done with cxmon, call mon_exit().
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History
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-------
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Please consult the file "ChangeLog" for the release history.
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Christian Bauer
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www.cebix.net
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Marc Hellwig
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<Marc.Hellwig@uni-mainz.de>
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