Re: Problem with PowerPC Altivec engine

>> It fails about one time in 5 or so.
>
> I'm guessing that it fails more often when higher bit counts are used  
> - the bug appears to be in the "wraparound" code used when more than  
> 2^31 iterations are needed to find a collision.  The problem is that  
> when wrapping, the "tail" position is not reset, but it is updated in  
> the body of the loop.

This indeed seems to be the case - I fixed that bug, and got 10 good  
stamps in a row immediately afterwards.

Arowana:~/download/hashcash-1.16 chromi$ ./hashcash -m -b 29 -r  
71672bc400000017-000003c2-0001.rpow.net
hashcash token:  
1:29:050131:71672bc400000017-000003c2-0001.rpow.net::PFQGGOfPKOqjhbaH: 
000000000000000000000Bz0iQ
Arowana:~/download/hashcash-1.16 chromi$ ./hashcash -m -b 29 -r  
71672bc400000017-000003c2-0001.rpow.net
hashcash token:  
1:29:050131:71672bc400000017-000003c2-0001.rpow.net::dMztK30vhsezAoYa: 
0000000000000000000007nR7k
Arowana:~/download/hashcash-1.16 chromi$ ./hashcash -m -b 29 -r  
71672bc400000017-000003c2-0001.rpow.net
hashcash token:  
1:29:050131:71672bc400000017-000003c2-0001.rpow.net::XhZt2zcDoqAtL6yR: 
0000000000000000000006N7nk
Arowana:~/download/hashcash-1.16 chromi$ ./hashcash -m -b 29 -r  
71672bc400000017-000003c2-0001.rpow.net
hashcash token:  
1:29:050131:71672bc400000017-000003c2-0001.rpow.net::sL8B5qLFKoj8duDF: 
000000000000000000000kpbPL
Arowana:~/download/hashcash-1.16 chromi$ ./hashcash -m -b 29 -r  
71672bc400000017-000003c2-0001.rpow.net
hashcash token:  
1:29:050131:71672bc400000017-000003c2-0001.rpow.net::0CWPrpTceaFJFxCY: 
000000000000000000000Jx1Cd
Arowana:~/download/hashcash-1.16 chromi$ ./hashcash -m -b 29 -r  
71672bc400000017-000003c2-0001.rpow.net
hashcash token:  
1:29:050131:71672bc400000017-000003c2-0001.rpow.net::343tGahxKEBnbjgw: 
000000000000000000000dfzkm
Arowana:~/download/hashcash-1.16 chromi$ ./hashcash -m -b 29 -r  
71672bc400000017-000003c2-0001.rpow.net
hashcash token:  
1:29:050131:71672bc400000017-000003c2-0001.rpow.net::ZIw+oWdHFLQ3Spno: 
000000000000000000000WjvrU
Arowana:~/download/hashcash-1.16 chromi$ ./hashcash -m -b 29 -r  
71672bc400000017-000003c2-0001.rpow.net
hashcash token:  
1:29:050131:71672bc400000017-000003c2-0001.rpow.net::OU3oKHlEPdxt2eoa: 
0000000000000000000004EtCU
Arowana:~/download/hashcash-1.16 chromi$ ./hashcash -m -b 29 -r  
71672bc400000017-000003c2-0001.rpow.net
hashcash token:  
1:29:050131:71672bc400000017-000003c2-0001.rpow.net::watWd9k1NxsOgbNv: 
0000000000000000000003y+1m
Arowana:~/download/hashcash-1.16 chromi$ ./hashcash -m -b 29 -r  
71672bc400000017-000003c2-0001.rpow.net
hashcash token:  
1:29:050131:71672bc400000017-000003c2-0001.rpow.net::tvr0Rh0pt4lrfPYi: 
000000000000000000000Sg2NP



--------------------------------------------------------------
from:     Jonathan "Chromatix" Morton
mail:     [email protected]
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