PIC 18 Disassembler

Disassembler for Microchip's PIC 18 family.

Download

Download Python code (for those that have Python installed); size=5k
Download windows executable (build from Python using py2exe), size=470k

Usage

python picdis18.py [-l] [-o outputfile] inputfile
or
picdis18.exe [-l] [-o outputfile] inputfile

History

June, 2003 - I have searched the web for a pic18 disassembler and found none, so I said I'll do it. I decided to write it in Python, after I saw how nice Mel Wilson's wrote his dispic16.py;
v0.3 added support for eeprom & configuration words;
v0.4 some options;

Features

does not disassemble empty memory locations, instead uses ORG directives;
displays SFR names;
allocate symbolic names for goto/branch/call (the label name contains the address in hex of the current location);
for each procedure (or jump destination) all callers addresses are listed;
for better visibility empty lines are inserted before location that have many callers;
in "list" mode, the address and binary value for each line is displayed, insertion of empty lines is suppressed, second word of the double-word instructions is displayed as ";nil" (I'm talking about the special NOP instruction);
can be loaded into MPLAB and reassembled immediately without any problems, although the processor type should be changed (default 18F252);
Below there is an example of a small program written in MPLAB (which does nothing), assembled, and the resulting hex disassembled. When disassembling a .hex file, the best way to verify everything worked correct is to reassemble the obtained _.asm file (in mplab) and compare the two hex files; if there are differences, hmm, then there could be a bug in my program (mail me!).

Original code: dis18.asm	Assembled with mplab, then disassembled: dis18_.asm
RADIX DEC LIST P=18F252 #include "p18f252.inc" __CONFIG _CONFIG1H, _OSCS_OFF_1H & _HS_OSC_1H ; EEPROM values: ORG 0xF00000 DE "Ok" ORG 0x0 goto start ORG 0x100 start movlw 0x6 decf PORTA,W rlcf TRISA addwf 0x23,W,BANKED addwfc 0x23,f,BANKED cpfslt 0x23 cpfslt 0x23,BANKED btg 0x23,0,BANKED bc start bra start rcall undeva call undeva,FAST push pop undeva tblrd*+ lfsr 0x2,0xBAC movff 0x123,0x456 movff WREG,STATUS return FAST END	;Select your processor LIST P=18F252 ; modify this #include "p18f252.inc" ; and this __CONFIG 300000h, FAFFh ;eeprom: ORG F00000h DE 6B4Fh ORG 0x0 goto p__100 ORG 0x100 p__100 movlw 6 ; entry from: 0,110h,112h decf PORTA,W rlcf TRISA addwf 23h,W,BANKED addwfc 23h,f,BANKED cpfslt 23h cpfslt 23h,BANKED btg 23h,0,BANKED bc p__100 bra p__100 rcall p__11E call p__11E,FAST push pop p__11E tblrd*+ ; entry from: 114h,116h lfsr 2,0BACh movff 123h,456h movff WREG,STATUS return FAST END
	python picdis18.py -l -o dis18_.lst dis18.hex
	;Select your processor LIST P=18F252 ; modify this #include "p18f252.inc" ; and this 300000 FAFF ;eeprom: F00000 6B4F 00000 EF80 goto p__100 00002 F000 ;nil 00100 0E06 p__100 movlw 6 ; entry from: 0,110h,112h 00102 0480 decf PORTA,W 00104 3692 rlcf TRISA 00106 2523 addwf 23h,W,BANKED 00108 2323 addwfc 23h,f,BANKED 0010A 6023 cpfslt 23h 0010C 6123 cpfslt 23h,BANKED 0010E 7123 btg 23h,0,BANKED 00110 E2F7 bc p__100 00112 D7F6 bra p__100 00114 D804 rcall p__11E 00116 ED8F call p__11E,FAST 00118 F000 ;nil 0011A 0005 push 0011C 0006 pop 0011E 0009 p__11E tblrd*+ ; entry from: 114h,116h 00120 EE2B lfsr 2,0BACh 00122 F0AC ;nil 00124 C123 movff 123h,456h 00126 F456 ;nil 00128 CFE8 movff WREG,STATUS 0012A FFD8 ;nil 0012C 0013 return FAST END