findflips (c) 2023 Jacek Lipkowski SQ5BPF <sq5bpf@lipkowski.org>

This is a simple utility to compare two files of the same size, 
show which bytes have changed, and which bits have changed.


The output is supposed to be easy to read, especially if there is
a small amount of changes.

Changed parts of the files are shown as 16-byte blocks, with the
changed bytes underlined by ^^ and a handy hexdump on the right.

I wrote it to ease reverse engineering of the configuration memory
of various handheld radios and similar devices. 


###### Usage:

Usage:

./flipbits file1 file2

file1 and file2 have to be the same size.


######  Example output:

There are two sources d1 and d2, they differ in the bytes 0x0e80, 0x0e81,
and 0x0ea1. 

The ^^ characters show the bytes that have changed in the hexdump.



The changed bytes are then shown separately. For example for byte at
offset 0x0e80:

0x0e80: d1: 0xcd (205)   d2: 0x00 (000)
0xcd 11001101
0x00 00000000
     76  32 0

In the original the value was 0xcd (205 decimal), in the changed file it
is 0x00 (0 decimal).

The numbers below the bits show which bits have changed, and their
positions. For example for byte 0x0e80  the bits 7, 6, 3, 2, 0 have
changed their state.


   0x000e80 |0 |1 |2 |3 |4 |5 |6 |7 |8 |9 |a |b |c |d |e |f |
   ---------+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+------------
d1 0x000e80: cd 02 cd 00 00 cd cf cf ff ff 00 00 ff ff ff ff   ................   
d2 0x000e80: 00 00 cd 00 00 cd cf cf ff ff 00 00 ff ff ff ff   ................   
>            ^^ ^^                                           
0x0e80: d1: 0xcd (205)   d2: 0x00 (000)
0xcd 11001101
0x00 00000000
     76  32 0


0x0e81: d1: 0x02 (002)   d2: 0x00 (000)
0x02 00000010
0x00 00000000
           1 



   0x000ea0 |0 |1 |2 |3 |4 |5 |6 |7 |8 |9 |a |b |c |d |e |f |
   ---------+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+------------
d1 0x000ea0: 00 ff ff ff ff ff ff ff 01 00 00 00 ff ff ff ff   ................   
d2 0x000ea0: 00 01 ff ff ff ff ff ff 01 00 00 00 ff ff ff ff   ................   
>               ^^                                           
0x0ea1: d1: 0xff (255)   d2: 0x01 (001)
0xff 11111111
0x01 00000001
     7654321