vPICdisasm - Free Mid-Range PIC Disassembler

Download the latest version of vPICdisasm source here: vpicdisasm-1.0.tar.gz

Download a Mac OS X Intel binary (compiled on 10.4.8) of vPICdisasm here: vpicdisasm-intel-osx-1.0.gz

Download a Linux x86 binary of vPICdisasm here: vpicdisasm-linux-x86-1.0.gz

ChangeLog

• Version 1.0 - 2007/01/06
  • Initial release.

vPICdisasm is an PIC Mid-Range MCU family program disassembler. It supports all 35 PIC instructions, plus the two deprecated ones (”option” and “tris”) as defined by the PICmicro Mid-Range MCU Family Instruction Set, document DS31029A.

This single-pass disassembler can handle Intel HEX8, and Motorola S-Record formatted files containing valid PIC program binaries.

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 platform, including a Cygwin environment. vPICdisasm was written in C by Vanya A. Sergeev - vsergeev at gmail, and tested with the GNU C Compiler.

vPICdisasm is released under the GNU General Public License.

    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 HEX8, 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 HEX8, or Motorola S-Record formatted files, respectively.

Option –no-addresses

By default, vPICdisasm will print the instruction addresses alongside disassembly, but this can be disabled with the –no-addresses option.

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.

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

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, every jump and call instruction will be formatted to jump to its 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, and 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 (i.e. showing “eor” in additon to “clr”). This technically means that the “cbr” instruction can never be displayed in the disassembly because the “andi” instruction precedes 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).

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 “R” for register operands or “$” for data operands) can be customized in the format_disasm.h header file.

Field width spacing of the addresses printed alongside disassembly, and the destination relative address comments can be customized in the ui_disasm.c source file.

The output file (default is stdout) can be changed in ui_disasm.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 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'