Help with first disassembly

[evofan]

Though id have a go at some ecu disassembly for myself and so far so good i pulled this rom from a friend of mines car, shes a non turbo JDM car running a H8 ecu :lol: and ive gotten all the important tables however im a little stuck on the scaling tables for everything as you will see from the attached rom can anybody help me and point me in the right direction? and if possible not just change the rom but show me what to look in the rom for and were :smile:

and before anybody asks why im tuning a basic car im not just trying to teach myself disassembly as its tough to find all the information in the one place and wanted to pull a rom on something i couldnt cheat at by finding a XML somewhere :p

[sr5guy]

I found the scalars by back searching where the tables were referenced from. Usually there is a "common" 3D table calculation routine within the code, especially if there are more than a few of the tables. For my Honda ECU project I'm working on, it loads the 1st address of the table, RPM Scalars & RPM, Load Scalars & Load into 5 registers R0-R4 and jumps to the calculation routine. The routine returns the result in R5.

If you have the code disassembled, search the code for the location of the tables and see if there is some type of common calculation routine.


48FF 5AA3A0 MOV:I.W #H'A3A0:16,R2 ;2nd Fuel Map (EGR Active)
4902 589D4E MOV:I.W #H'9D4E:16,R0 ;Load Scalers
4905 599D24 MOV:I.W #H'9D24:16,R1 ;RPM Scalers
4908 15FCB483 MOV:G.B @H'FCB4:16,R3 ;MAP 11 (8bit) (calc load)
490C 1DFC5084 MOV:G.W @H'FC50:16,R4 ;RPM 16Bit
4910 1866F4 JSR @H'66F4 ;Common 16 Bit Table Calculation Routine
~
4919 1DFD5295 MOV:G.W R5,@H'FD52:16 ;Current injector pulse width from map



Also if you have Tunerpro from Mark Mansur, there is a nifty feature of the program called 2D data viewer that makes 8bit and 16bit data scales stick out like a sore thumb. Here, you can see from the code above the 16bit RPM Scale at 9D24 (1D24) and the 8bit load scaler a little bit later at 9D4E (1D4E). After the load scale is the ignition map - see the pattern and how it sticks out? I quickly fell in love with this little utility!

http://i106.photobucket.com/albums/m273/sr5guy/2DTunerproDemo.jpg

-Matt

[evofan]

cheers for the reply matt, il take a look at the code now see if i can spot a common routine, i downloaded tunerpro and it loads the rom but is looking for its own XDF definition file to delve into it further :(

[sr5guy]

cheers for the reply matt, il take a look at the code now see if i can spot a common routine, i downloaded tunerpro and it loads the rom but is looking for its own XDF definition file to delve into it further :(

I didn't need to load an XDF to use the 2D data viewer - load the bin, drop down the Tools menu, goto Advanced and hit "2D Data Viewer". And, if you have an XML file you should be able to easily create an XDF from those definitions.

-Matt

[evofan]

still stuck on this if anybody could help is there another way other than above as the 2d data viewer does not show my complete rom