Last modified 2013-10-10 23:01:22 PDT

vPICdisasm - Microchip PIC Disassembler

Note: This project will soon be replaced by ucdisasm.

Git: git clone git://github.com/vsergeev/vPICdisasm.git

Github: http://github.com/vsergeev/vPICdisasm

Latest source: vpicdisasm-master zip

Arch Linux AUR Package: http://aur.archlinux.org/packages.php?ID=46700

Please feel free to report any issues at github or by email at vsergeev at gmail.


ChangeLog

ABOUT vPICdisasm

vPICdisasm is a Microchip PIC firmware disassembler that supports the Baseline, Mid-Range, and Mid-Range Enhanced 8-bit PIC cores. This single-pass disassembler can read Intel HEX8 and Motorola S-Record formatted files containing valid PIC program binaries.

vPICdisasm fully supports all 35 Mid-Range PIC instructions (as well as the two deprecated ones: “option” and “tris”), the additional 21 Mid-Range Enhanced PIC instructions, and the 33 Baseline PIC instructions.

vPICdisasm features a handful of formatting options, including:

vPICdisasm should work on most *nix platforms, including a Cygwin or MinGW environment. vPICdisasm was written by Vanya A. Sergeev, and tested with the GNU C Compiler on Linux. Feel free to send any ideas or suggestions to vsergeev at gmail dot com.

LICENSE

vPICdisasm is released under the GNU General Public License Version 2.

    You should have received a copy of the GNU General Public License
    along with this program; see the file "COPYING".  If not, visit
    http://www.gnu.org or write to the Free Software Foundation, Inc.,
    59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.

COMPILING vPICdisasm

Simply by running,

$ make

in the vPICdisasm project directory should compile vPICdisasm on most *nix systems, including a Cygwin or MinGW environment. The Makefile is configured to use GCC to compile vPICdisasm.

vPICdisasm should have no problem being compiled with “gmake”.

USING vPICdisasm

File Input

For most purposes:

$ vpicdisasm <PIC program file>

Example:

$ vpicdisasm sampleprogram.hex

Use - for standard input.

vPICdisasm will assume the Mid-Range PIC architecture by default. You can specifiy an alternate architecture with the -a or --architecture option.

Example:

$ vpicdisasm -a enhanced sampleprogram.hex

Option -t or --file-type

vPICdisasm will auto-recognize Intel HEX8, and Motorola S-Record files by their first character. However, the -t or --file-type option can be used to explicitly select the file format. Example:

$ vpicdisasm -t ihex sampleprogram

The file type argument for this option can be “ihex”, or “srecord” for Intel HEX8 or Motorola S-Record formatted files, respectively.

Option -o or --out-file «output file»

Specify an output file for writing instead of the standard output. The output file - is also synonymous for standard output.

Option -a or --architecture

vPICdisasm supports the Baseline, Mid-Range, and Mid-Range Enhanced 8-bit PIC cores. The architecture can be specified with this option, followed by the architecture identifier (right side of the list below):

	Baseline            baseline
	Mid-Range           midrange (default)
	Mid-Range Enhanced  enhanced

Option --original

Print the original opcode data to the left of the disassembly. Note: this option is ignored if address labels are enabled (to ensure assemble-able code).

Options --literal-hex, --literal-bin, --literal-dec

vPICdisasm can represent literal operands in either hexadecimal, decimal, or binary bases. The base can be specified with the --literal-hex, --literal-bin, and --literal-dec options.

Options --literal-ascii

Display the ASCII value of a literal operand in an assembly comment.

Options --no-addresses, --no-destination-comments

By default, vPICdisasm will print the instruction addresses alongside disassembly and destination comments for relative branch, jump, and call instructions. These formatting options can be disabled with the --no-addresses and --no-destination-comments options, respectively.

Options -l or --address-label

See the Ghetto Address Labels section.

Options -h or --help, -v or --version

The -h or --help option will print a brief usage summary, including supported program options and file types. The -v or --version option will print the program’s version number.

If you encounter any program bugs or problems, please notify the program author by email: Vanya A. Sergeev - vsergeev at gmail dot com.

Additional Usage Information

Additional usage information from the program’s help is provided below.

Usage: vpicdisasm <option(s)> <file>
 Disassembles PIC program file <file>. Use - for standard input.
 Written by Vanya A. Sergeev - <vsergeev@gmail.com>.

 Additional Options:
  -o, --out-file <output file>	Write to output file instead of standard output.
  -a, --arch <architecture>	Specify the 8-bit PIC architecture to use
				during disassembly.
  -t, --file-type <type>	Specify the file type of the object file.
  -l, --address-label <prefix> 	Create ghetto address labels with 
				the specified label prefix.
  --original                    Print original opcode data alongside
				disassembly.
  --no-addresses		Do not display the address alongside
				disassembly.
  --no-destination-comments	Do not display the destination address
				comments of relative branch instructions.
  --literal-hex			Represent literals in hexadecimal (default)
  --literal-bin			Represent literals in binary
  --literal-dec			Represent literals in decimal
  --literal-ascii		Show ASCII value of literal operands in a
				comment
  -h, --help			Display this usage/help.
  -v, --version			Display the program's version.

Supported 8-bit PIC Architectures:
  Baseline              baseline
  Mid-Range             midrange (default)
  Enhanced Mid-Range    enhanced

Supported file types:
  Intel HEX8            ihex
  Motorola S-Record     srecord

Ghetto Address Labels

vPICdisasm supports a unique formatting feature: Ghetto Address Labels, which few, if not any, single-pass disassemblers implement.

With the -l or --address-label option and a supplied prefix, vPICdisasm will print a label containing the ideally non-numerical supplied prefix and the address of the disassembled instruction at every instruction. Also, all relative branch, jump, and call instructions will be formatted to jump to their designated address label.

This feature enables direct re-assembly of the vPICdisasm’s disassembly. This can be especially useful for quick modification of the PIC program assembly code without having to manually format the disassembly or adjust the relative branch, jump, or call distances with every modification to the disassembly.

The -l or --address-label option overrides the default printing of the addresses alongside disassembly. Destination comments option can still be used.

Example:

$ vpicdisasm -l “A_” sampleprogram.hex

vPICdisasm’s disassembly will include address labels that will look like this: A_0000.

For sample disassembly outputs by vPICdisasm, see the Sample Disassembly Outputs section.

Shortcomings

Currently,

These features do not affect the accuracy of the disassembler’s output, and may be supported in future versions of vPICdisasm.

Source Code

vPICdisasm’s source code is heavily commented, because this disassembler was also a personal learning project of the author.

Operand prefixes (such as “0x” for address operand) can be customized in the format.h header file.

Field width spacing of the addresses printed alongside disassembly can be customized in the ui.c source file.

vPICdisasm uses libGIS, a free Atmel Generic, Intel HEX8, and Motorola S-Record Parser Library to parse formatted files containing PIC program binaries. libGIS is available for free under both MIT and a Public Domain licenses here. libGIS is compiled into vPICdisasm—it does not need to be obtained separately.

Sample Disassembly Outputs

Here are a few sample disassembly outputs illustrating the various formatting options and disassembly settings vPICdisasm supports:

$ vpicdisasm sampleprogram.hex
   0:   movlw 0x0
   1:   tris 0x06
   2:   movlw 0xFF
   3:   movwf 0x06
   4:   goto 0x004
$ vpicdisasm --original sampleprogram.hex
   0:   30 00           movlw 0x0
   1:   00 66           tris 0x06
   2:   30 FF           movlw 0xFF
   3:   00 86           movwf 0x06
   4:   28 04           goto 0x004
$ vpicdisasm --no-addresses sampleprogram.hex
movlw 0x0
tris 0x06
movlw 0xFF
movwf 0x06
goto 0x004
$ vpicdisasm --literal-bin sampleprogram.hex
   0:   movlw b'00000000'
   1:   tris 0x06
   2:   movlw b'11111111'
   3:   movwf 0x06
   4:   goto 0x004
$ vpicdisasm -l "A_" sampleprogram.hex

org 0x000
A_000 movlw 0x0
A_001 tris 0x06
A_002 movlw 0xFF
A_003 movwf 0x06
A_004 goto A_004
end
$ vpicdisasm --literal-ascii sampleprogram2.hex
   0:   retlw 0x48      ; 'H'
   1:   retlw 0x45      ; 'E'
   2:   retlw 0x4C      ; 'L'
   3:   retlw 0x4C      ; 'L'
   4:   retlw 0x4F      ; 'O'

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