English Amiga Board - Disassembler

Not possible ATM. The only way is to change 2016(A4) to the library base then run the tool again. Which I admit is a weakness of the tool because you destroy the -offset(A4) address so the tool can detect LVOs. And if you want to reassemble the code, you can't. No biggie for me most of the time because i only use those sources for reverse engineering, but...

That would be much better to provide a configuration file to specify that those offsets are actually library bases. I may do that in a next future.

About those A4 register-based variables that are hell... I know IRA can handle them, and so yesterday I added this feature as well here.

say you have located the LEA to A4 in your code:

Code:

LEA lb_00314+32766,A4 ;2b2be: 49f900008312

use cheapres like this

Code:

cheapres.py -i source.asm -b A4:2b2be

cheapres.py: Base offset for A4 is $8312

cheapres parses the LEA expression (can't be too complex either!) and computes offset for A4. Then it's able to link the A4 addresses to offsets by annotating them in comments

Code:

MOVE.L A7,-13628(A4) ;2b268: 294fcac4 (links:aka=lb_04dd6)

I have added the ability to recognize jump tables in DATA section so

Code:

   dc.w  $4EF9

   dc.w  some_func

becomes

Code:

jmp some_func

Also, the A4 link checks if the offset contains a label (as shown above), if it doesn't, it tries to see if it's not _jumping_ to a label (idirection) and sets link accordingly.

To conclude, cheapres also detects wrapper functions that just get args from stack and JMP to OS function. Both features above are illustrated below

Code:



lb_2b474:

        JMP        -30780(A4)                ;2b474: 4eec87c4 (links:jmp=dos_Rename)



        SECTION S_67,CODE



dos_Rename:

        MOVEM.L        4(A7),D1-D2                ;2b478: 4cef00060004

        MOVEA.L        DosBase,A6                ;2b47e: 2c6ccad0

        JMP        (_LVORename,A6)        ;2b482: 4eeeffb2 dos.library (off=-78)

        DC.W        $0000                        ;2b486

We see that as soon as DosBase has been identified and set, the tool detects the wrapping function. And when it detects it, it also detects the other fake wrapping function that calls it (renaming of lb_2b474 isn't done, do it manually)

available in my repository now.