CompuServe Messages

#"Unused" 8085 opcodes

    14-Jul-85 13:09:34
Sb: #"Unused" 8085 opcodes
Fm: Tim Peters 72227,2416
To: Gary Bender 70375,1070
Gary, I'm a CIS newcomer, so if you sell an M100 Forth, it's news to me – interested in knowing more! Comment: before I lost interest, I was implementing a TIL for the M100. HL was the "natural" choice for the data stack pointer, UNTIL I doped out the mystery opcodes: DE is a much better choice if you use 'em (leaves HL free for arithmetic, and the D9 & ED opcodes allow DE to be used as an indirect adr for full-word load/stores of HL). It is, I admit, frightening to have such a BASIC design decision dependent on presumably unsupported features!… tim *** There is a reply: 85504 Enter command, N for next message or <ENTER> for menu:n