🚀 go-pugleaf

>The reason the high byte gets trashed in SumacC code has nothing to do
>with the Mac hardware, but instead is a side-effect of the Sumacc
>relocation scheme.

You are quite correct about sumacc method, which I am aware of.  My question
had to do with the 68000 Load Effective Address (lea) instruction itself.
When I wrote some assembly language code to support my C code, it seemed
that the lea instruction itself was putting something in the high byte.
So after I did a lea to an address register and then moved it to a data
register, I found I had to clear the high byte to use it the way I wanted
or otherwise the high byte would screw things up.

Edward Moy
Computing Services
University of California
Berkeley, CA  94720

edmoy@ucbopal.ARPA
ucbvax!ucbopal!edmoy