can you explain that why the test you mentioned
works?
Consider
ax+0xff
changes the 0x100 bit iff the low-order byte of ax is not zero.
~ax
always changes the 0x100 bit.
(~ax^(ax+0xff)) 0x100
is zero iff both ~ax and ax+0xff have the same thing at the 0x100
position.
You can extend
This is highly optimized code that in the normal case loads 4 bytes at
a time, checks if any of the 4 is z a null (0) and handles accordingly.
If the string doesn't start on a 4-byte boundary, the str_misaligned
counts 1, 2, or 3 characters until a null or alignment boundary is
found. The
