I tried this code in my assembler, set to 16 bit mode:
rep mov ds, ax
Surprisingly, no error was thrown. Is this even valid? Wasn't rep only supposed to work with string instructions? Is it ...
On a recent trip to the London Science Museum I saw Babbage’s Analytical Engine.
Apparently this had an ALU (or equivalent). I can build an ALU out of logic gates but I can’t conceptualise how to do ...
The M6800 had a few illegal opcodes, including the (in)famous HCF (Halt and Catch Fire). The following illegal opcodes were revealed in BYTE Magazine, December 1977:
$87: STAA immediate