vPICdisasm - Microchip PIC Disassembler

Download the latest version of vPICdisasm source here: vpicdisasm-1.2.tar.gz

Download the latest Linux x86 binary of vPICdisasm here: vpicdisasm-linux-x86-1.2.gz

ChangeLog

• Version 1.2 - 07/28/2009
  • ui.c, format.c, format.h, file.c, file.h: Added support for Baseline and Mid-Range Enhanced PIC cores.
  • format.c: Updated destination register operand formatting to print W/F instead of 0/1.
  • Renamed source files to make more sense and for better organization of code.
• Version 1.1 - 07/20/2009
  • file_disasm.c, libGIS: Fixed handling of newlines (sometimes found at the end of program files) so an “invalid record” error doesn't appear when a newline is encountered.
  • CRITICAL FIX: Fixed reading and disassembly of odd byte length records in Intel Hex and Motorola S-Record files. Special thanks to Ahmed for discovery and patch!
  • format_disasm.c: Fixed a few small bugs/typos for cleaner compilation.
• Version 1.0 - 01/06/2007
  • Initial release.

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:

• Printing the instruction addresses alongside disassembly, enabled by default
• Ghetto Address Labels (see Ghetto Address Labels section)
• Literal operands represented in either hexadecimal, binary, or decimal bases, and as ASCII in an assembly comment
• Data word directive for data not recognized as an instruction during during disassembly

vPICdisasm should work on most *nix platforms, including a Cygwin 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.

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.

Simply by running,

$ make

in the vPICdisasm project directory should compile vPICdisasm on most *nix systems, including a Cygwin environment. The Makefile is configured to use GCC to compile vPICdisasm. vPICdisasm should have no problem being compiled with “gmake”.

File Input:

For most purposes, just type

$ ./vpicdisasm <PIC program file>

Example:

$ ./vpicdisasm sampleprogram.hex

vPICdisasm will auto-recognize Intel HEX, and Motorola S-Record files by their file extensions, but if it fails to do so, use the the -t or --file-type option to specify the file format. Example:

$ ./vpicdisasm -t ihex sampleprogram

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

vPICdisasm will assume the Mid-Range PIC architecture by default, you can specifiy an alternate architecture with the --architecture option. Example:

$ ./vpicdisasm -m enhanced sampleprogram.hex

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 --no-…

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.

Option --literal-…

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.

Option --literal-ascii

With this option, vPICdisasm will dipslay the ASCII value of a literal operand as an assembly comment.

Option -l or --address-label

For usage information on the -l or --address-label option see the Ghetto Address Labels section.

Option -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.

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

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

 Additional Options:
  -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.
  --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 HEX                     ihex
  Auto-recognized with .hex, .ihex, and .ihx file extensions.

  Motorola S-Record             srecord
  Auto-recognized with .srec and .sre file extensions.

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 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.

• vPICdisasm does not disassemble and display alternate versions of the same encoded instruction. This technically means that some instructions can never be displayed in the disassembly because another instruction may precede it in priority.
• vPICdisasm does not display the original opcode of the disassembled instruction. The original opcode can be convenient for some disassembled instructions that were actually meant to be data words (data directive).
• vPICdisasm does not yet support the PIC18 architecture.

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

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.

The output file (default is stdout) can be changed in ui.c source file.

vPICdisasm uses libGIS, a free Atmel Generic, Intel HEX, and Motorola S-Record Parser Library to parse formatted files containing PIC program binaries. libGIS is available for free under a Public Domain license here.

libGIS is compiled into vPICdisasm–it does not need to be obtained separately.

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 --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'