Is there a $F0 source/assembly file anywhere?

[scorp508]

Originally Posted by tiegsd

Rgr. I was poking around last week for a motorola chip diassembler, looks there are a few running around of unknown (to me anyway) quality, and IDA may be able to do it in the paid version, still looking into that.

Any idea what type of processor these were these based on back in the day? I could try to lean on some of my professional contacts if I can give them a hint of what they're disassembling.

[tpepmeie]

Motorola 68HC11
if that's what you are asking.

[tpepmeie]

Many many years ago I made a complete, fully commented disassembly of BFXB, and BMCB. Had the others partially complete but moved on to other things. Had full access to the source code to add, delete, routines and reassemble. It worked, I added closed loop lambda control at one point. I had a lot more free time in my 30s I guess... LOL

[scorp508]

Originally Posted by tpepmeie

Many many years ago I made a complete, fully commented disassembly of BFXB, and BMCB. Had the others partially complete but moved on to other things. Had full access to the source code to add, delete, routines and reassemble. It worked, I added closed loop lambda control at one point. I had a lot more free time in my 30s I guess... LOL

Annnnnd those files now reside where?

Beer money to your Venmo/Paypal is waiting.

[scorp508]

For what it's worth it has been recommended I give Ghidra (https://ghidra-sre.org/) a try for disassembly. The NSA created it.... so who knows what else it'll install on my machine.

[tpepmeie]

I found an old presentation I did at the Gathering in 2004. Attached.

https://toddpepmeier.wixsite.com/pep...-presentations

[tpepmeie]

If I remember, the "ANHT" hac was more closely related to the LT5 code at the time. It almost seemed like the various operating code sections were pulled from a menu and inserted into whatever calibration they needed to create at the time. All the LT5 calibrations are similar, but you can tell over time where they added some tweaks and minor functionality here and there. The BMCB version strikes me as the most advanced. Makes sense since it was among the final releases.

Here's a snippet of the BFXB code, which determines the target air-fuel ratio in open loop, and then applies the richest of the calculated ratios to determine the final ratio.

******************************************************
** OPEN LOOP/CLOSED LOOP FUEL/AIR RATIO CALCULATION
******************************************************
OLCLAIRF       CLRA
               LDAB   FATI                                     TIMEOUT A/F RATIO
               ADDB   KFABIAS                                         OPEN LOOP F/A BIAS USED TO SET UP LEAN LIMIT
               ADCA   #0
               ADDB   FATC                                     COOL TEMP F/A RATIO OFFSET
               ADCA   #0
               PSHB
               PSHA
               BRSET  MWFA1;BIT7,FAADDVAP                      1=CLOSED LOOP MODE (BOTH SENSORS CL)

******************************************************
*** ADD MAP BASED TERM (VAPORIZATION FACTOR) IF IN OPEN LOOP
******************************************************
               LDAA   NMAPLD                                   NORMALIZED MAP VALUE
               LDX    #F50H                                           OPEN LOOP FUEL/AIR % CHANGE V. MAP
               JSR    P4LKUPQ                                  2D TABLE LOOKUP, NO OFFSET, SPACED 16
               STAA   FAVAPF                                   FUEL/AIR VAPORIZATION FACTOR
FAADDVAP       PULA
               PULB
               ADDB   FAVAPF                                   FUEL/AIR VAPORIZATION FACTOR
               ADCA   #0

******************************************************
*** APPLY ALL FUEL/AIR MODIFICATION TERMS TO STOCHIOMETRIC
******************************************************
MULFAST        LDX    KFASTCN                                         STOCHIOMETRIC A/F RATIO
               JSR    P4M1616C                                 16X16 MULTIPLY RETURN W/ MIDDLE 2 BYTES
               STD    FAVALNPE                                 NON-PWR ENRICH F/A VALUE

******************************************************
** PE FUEL-AIR RATIO CALCULATION
******************************************************
               BRCLR  MWFA;BIT5,PEAIRFLX                       1=POWER ENRICHMENT ACTIVE

               LDX    #F68E                                           POWER ENRICH FUEL/AIR % CHG V. RPM
               LDAA   NTRPMX                                   RPM/25
               CMPA   #160
               BHI    PEAF001
               SUBA   #16
               BCC    PEAF002
               CLRA
               BRA    PEAF002

PEAF001        LDAA   NTRPMZ                                   RPM/31.25
               ADDA   #16
               BCC    *+4
               LDAA   #255
PEAF002        JSR    P4LKUPQ                                  2D TABLE LOOKUP, NO OFFSET, SPACED 16
               TAB
               LDX    #128
               ABX
               LDAB   LKUPF67                                  F67 LOOKUP IN 100 MSEC COOLVAR
               ABX
               LDD    KFASTCN                                         STOCHIOMETRIC A/F RATIO
               JSR    P4M1616C                                 16X16 MULTIPLY RETURN W/ MIDDLE 2 BYTES
               STD    FAVALPE                                  PWR ENRICH F/A VALUE
PEAIRFLX       EQU    *

******************************************************
* RICHEST FUEL/AIR RATIO (P.E. OR NON-P.E.) DETERMINATION LOGIC
******************************************************
FAVALUPD       LDX    FAVALPE                                  PWR ENRICH F/A VALUE
               CPX    FAVALNPE                                 NON-PWR ENRICH F/A VALUE
               BHI    *+5
               LDX    FAVALNPE                                 NON-PWR ENRICH F/A VALUE
LCB36          STX    FAVAL                                    FINAL TOTAL F/A VALUE

[tiegsd]

Originally Posted by scorp508

For what it's worth it has been recommended I give Ghidra (https://ghidra-sre.org/) a try for disassembly. The NSA created it.... so who knows what else it'll install on my machine.

[tiegsd]

Interesting stuff going on in those old ECUs. More complicated than I realized.