segment base corruption

[SpenserStyles]

I'm attempting to use YaCo v2.6 with IDA 7.0 on a 8051 code base that uses banking for code pages. The segment base is corrupted when opening the _local IDB. This appears to be caused by incorrect use of the ida_segment.get_segm_base() and ida_segment.set_segm_base().

The following steps can be used to replicate the issue:

• Create dummy binary file of size 0x20000

• Load into IDA select Intel 8051 leave rest as defaults and click OK until at disassembly view

• Open Program Segmentation and this is what you see:

• Modify Program Segmentation to values below

• Go to File->Script Command

• Enter following code

  
  import ida_segment
  # get segment base linear address
  seg = ida_segment.get_segm_by_name("B02")
  base = ida_segment.get_segm_base(seg)
  print(base)  # this prints 32768 when should be 2048

now when using set_segm_base(seg) it screws it up the base

ida_segment.set_segm_base(seg, base)

get segment base linear address

seg = ida_segment.get_segm_by_name("B03") base = ida_segment.get_segm_base(seg) print(base) # this prints 65536 when should be 4096

now when using set_segm_base(seg) it screws it up the base for segment B03

ida_segment.set_segm_base(seg, base)

![image](https://user-images.githubusercontent.com/31034116/48194567-62711380-e31b-11e8-957c-b827733297ba.png)

- Run script command
- Close and re-open Program Segmentation view and the BASE value has now been changed to incorrect values
![image](https://user-images.githubusercontent.com/31034116/48194557-59804200-e31b-11e8-8a93-494bc8e94a38.png)

YaCo is currently relying on get_segm_base() to return the value that should be used when calling set_segm_base().  This is incorrect.  I believe you must shift the value obtained by calling get_segm_base() right 4 bits for the value to use when calling set_segm_base().

Ultimately I think IDA may have this screwed up because I would have expected these to be complimentary functions.  I am unable to test this on IDA 7.1 so it could be possible that it may be corrected.

[bamiaux]

Thanks for the bug report, I've reproduced the bug on 7.2 & added the right shift on master. https://github.com/DGA-MI-SSI/YaCo/commit/9b85e6ca1809114c4df1382c11255f7e38408912 Please check if it fixes your issue. Note that IDA does not send any event when changing the segment base leading to potentially missing changes.