sha256 bug

[evgenykzz2]

Hi Nerds, i have found critical bug in nerdSHA256plus.cpp
There are invalid W size, it should be 64 bytes. I tested and compared with generic mbedtls_sha256_starts_ret.
Looks like current version calculates wrong sha256.

Also i have few optimization, i can increase hash rate up to 83KH/s.
Another thing - hardware sha256, hash rate is much better

Completed 0 share(s), 5678141 Khashes, avg. hashrate 130.87 KH/s

[BitMaker-hub]

Hi! this is interesting, can you write this into a PR or an issue to review it properly.
The current optimized lib was contrasted with other standard ones and there weren't any issue.
I also tested in past the hardware sha256 and directly I decided to not use it due to its poor timings.
Is surprising to me to know it's faster the Hw sha than the current lib

[evgenykzz2]

I have forked repo.
https://github.com/evgenykzz2/NerdMiner_v2
There is few thread fixes (i hope), crazy hashrate 197.80 KH/s (HW+SW).
Also i add mutex, and tiny nerdSha256 optimization.

About nerdsha256 bug. I got this message in debug:
nerdSHA256plus.cpp(666): error C4789: buffer 'W' of size 64 bytes will be overrun; 4 bytes will be written starting at offset 248

[BitMaker-hub]

Checked your work and looks pretty good, I'll try to test this week and create a PR. Seems a very cool achivement, congratulations!