Thanks that was a good tip.

I found one with a lookup table and stripped it down for micropyhton:

Code: Select all

```
_table = b'\x00\x07\x0e\t\x1c\x1b\x12\x158?61$#*-pw~ylkbeHOFATSZ]\xe0\xe7\xee\xe9\xfc\xfb\xf2\xf5\xd8\xdf\xd6\xd1\xc4\xc3\xca\xcd\x90\x97\x9e\x99\x8c\x8b\x82\x85\xa8\xaf\xa6\xa1\xb4\xb3\xba\xbd\xc7\xc0\xc9\xce\xdb\xdc\xd5\xd2\xff\xf8\xf1\xf6\xe3\xe4\xed\xea\xb7\xb0\xb9\xbe\xab\xac\xa5\xa2\x8f\x88\x81\x86\x93\x94\x9d\x9a\' ).;<52\x1f\x18\x11\x16\x03\x04\r\nWPY^KLEBohafst}z\x89\x8e\x87\x80\x95\x92\x9b\x9c\xb1\xb6\xbf\xb8\xad\xaa\xa3\xa4\xf9\xfe\xf7\xf0\xe5\xe2\xeb\xec\xc1\xc6\xcf\xc8\xdd\xda\xd3\xd4ing`ur{|QV_XMJCD\x19\x1e\x17\x10\x05\x02\x0b\x0c!&/(=:34NI@GRU\\[vqx\x7fjmdc>907"%,+\x06\x01\x08\x0f\x1a\x1d\x14\x13\xae\xa9\xa0\xa7\xb2\xb5\xbc\xbb\x96\x91\x98\x9f\x8a\x8d\x84\x83\xde\xd9\xd0\xd7\xc2\xc5\xcc\xcb\xe6\xe1\xe8\xef\xfa\xfd\xf4\xf3'
@Profiler.measure
def crc82(*args):
_sum = 0
table = _table
for arg in args:
for byte in arg:
_sum = table[_sum ^ byte]
return _sum
```

I transformed the table from a list to a bytes object because bytes objects don't get loaded into RAM while a list would. This reduced the time required to calculate the crc from 2.5ms to 740us.

However, the result is different, but I guess that's to be expected (and no problem if both sides use the same function)? The old function returned a crc of 170 and this one 39.