[erlang-questions] Fix width integer computations
Thu Dec 21 10:31:52 CET 2006
I have a C program that has a line of code like this:
mx = (z>>5 ^ y<<2) + (y>>3 ^ z<<4) ^ (sum^y) + (k[p&3 ^ e] ^ z);
All the variables are unsigned long
How do I code this in Erlang?
transcribe X >> N as trim(X bsl N)
X << N as trim(X bsr N)
X + Y as trim(X + Y)
X ^ Y as X bxor Y
where trim(X) = X band 16#ffffffff
Is this correct? - The result must be bit identical to the C code,
how many of the trims can I eliminate?
A nieve translation of (y>>3 ^ z<<4)
is trim(Y bsr 3) bxor trim(Z bsl 4)
identical to trim((Y bsr 3) bxor (Z bsl 4)) ????
(And for ten extra brownie points: identify the algorithm :-)
-------------- next part --------------
An HTML attachment was scrubbed...
More information about the erlang-questions