[appologies if posting too often bothers people, just have a lot to say 
at the moment. ]

In doing profile analysies on my code I came across something truly 
bizzare:

SmallInteger > bitAnd:  was, itself, calling  SmallInteger>  bitOr: !!!!

I thought "WTF?!?!?!?!"

and went to investigate. The code in interp.c was nearly what I had 
expected it to be.

I looked very closely at the code in bitAnd: and came to the conclusion 
that the primative implementation was stripping out the sign bit and 
that the code in the image was correcting for this with a kludge 
involving bitOr....

I'm probably wrong... What's the real story here?