0131: FF D3 9B STX LD39B
0134: 14 FCB $14
0135: 15 FCB $15
0136: 9B FCB $9B
0137: 19 FCB $19
0138: 18 FCB $18
0139: 1F FCB $1F
013A: 0F FCB $0F
013B: 1C FCB $1C
013C: 12 FCB $12
013D: 13 FCB $13
013E: 19 FCB $19
013F: 33 FCB $33
0140: 55 FCB $55
0141: 1A FCB $1A
0142: 04 FCB $04
0143: 1A FCB $1A
0144: 05 FCB $05
0145: 1A FCB $1A
0146: 05 FCB $05
0147: 1A FCB $1A
0148: 04 FCB $04
0149: 1A FCB $1A
014A: 05 FCB $05
014B: 1A FCB $1A
014C: 05 FCB $05
014D: 1A FCB $1A
014E: 04 FCB $04
014F: 1A FCB $1A
0150: 05 FCB $05
0151: 1A FCB $1A
0152: 05 FCB $05
0153: 01 FCB $01
0154: 01 FCB $01
0155: 0F FCB $0F
0156: 0F FCB $0F
0157: 15 FCB $15
0158: 15 FCB $15
0159: 15 FCB $15
015A: 15 FCB $15
015B: 0F FCB $0F
015C: 0F FCB $0F
015D: 15 FCB $15
015E: 15 FCB $15
015F: 15 FCB $15
0160: 15 FCB $15
0161: 0F FCB $0F
0162: 0F FCB $0F
0163: 15 FCB $15
0164: 15 FCB $15
0165: 15 FCB $15
0166: 15 FCB $15
0167: 01 FCB $01
0168: 01 FCB $01
0169: 13 FCB $13
016A: 1B FCB $1B
016B: 2B FCB $2B


this look an aweful lot like a data table to me. i just started dasm this rom form a turbo chrysler and this look like pure data any thoughts ?

 

Well it isn't FF so that means it's either one of 3 things. Tables, code, or space filler. What is the processor in the ecm? It's interesting to note the repitition. Just get ALL of the code in the ecm. Boy I wish we'd just focus on GM ecm's . I'm still find it amazing that somebody sat down and backwards engineered the GM ecm without actual official notes cool stuff.
What exactly is this application? I'm working on my own little side project. It's called the ford eec-iv with x2j (SHO Taurus) id. It isn't going so well.

 

its data out of a 87 turhbo chrysler ECM. it uses a 6801 MCU. ive been told numersous times that the chrysler code uses 2d table or something there of but here i see what looks to be a 3d data table. im starting to dasm the binary and dig thru the code. more for pratice then anything esle. it would be nice to be able to read more code then i currently do. that just looks so much like a data table. usually i like to start by finding data table and having the dasm go by them. then once i get the tables i start to workj the code out. just this one has me stumped.

there sevral small blocks of code that look like this.

 

could it be something repetative that the ecm is commanding...like wastegate function or some such? I'm no code hacker so if it is way off then you know why.

 

i also have a routine i think is for injector trim per cylinder. the turbo ecms for the 4cyl are sqeuntial. i found 4 calculatiosn with singel byte constants but i cant figure out what hardware there point at. i guess im gonna have to reverse engineer the hardware a bit mit and figure the I/O of the Mcu into everything. i was just tyring to get the dtat table blocked out for the dasm so i could get some decent code.

doesn anybody have a good techniuqe for spotting data tables ?

 

Yeah. But you have to know the table lookup routine first.
The table lookup math is not GM specific. It's Motorola specific.
Just like the 8X16 and 16X16 mult routines.

Then you can tell if it is a 2d, 3d lookup.

Does anything call those addresses with a LDX #$????


What disassembler are you using?

 

yes im getting ldxx calls to those points but what im not sure about is if the DASM isnt working correctly.

im using the tunercat cross dasm.

 

I sent you and Email.

 

Actually, they're only sequential on the 1990 and later units. 84-89 are all batch fire (2 banks).

I'm very interested in what you find on this, since I am doing the same thing right now (but I don't know the code at all)...

Email me if you'd like to discuss...


Matthew A. Green --- mattgreen(at)msquaredracing(dot)com
M"squared" Racing! --- http://www.msquaredracing.com/
85 Shelby Charger- 260hp, no waiting!
87 GLHS #314
90 Formula 350- I think I'll have a V8!
98 P-Neon SOHC- ACR wanna-be
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