HP-41 Byte Table

[JurgenRo]

(12-27-2018 09:18 PM)Thomas Okken Wrote:  They don't carry the same jump distance. That low nybble of the opcode is part of the offset!

If you construct a GTO or XEQ with an incorrect offset, the instruction will jump to an incorrect location, and undesired behavior will most likely result. You should construct your GTO and XEQ instructions with their offsets set to zero, and let the calculator find the label and calculate the offset when it first executes the code.

(I guess you do want pre-compiled offsets when you're generating code for use in ROMs, but I've never dealt with that.)

Ahhhh, ok, I see what you mean! Finally!! "That low nybble of the opcode is part of the offset!": that's what I missed. Thanks a lot again, Thomas! One will never stop learning when dealing with the 41