HP-45 Internal Pointer Operations

[Z80Sarah]

(04-24-2023 10:58 PM)brouhaha Wrote:  When p is decremented past 0, or incremented past 13, it wraps. It is never in a stable state of 14 or 15. There are some notes in internal HP docs that the pointer may "disappear" for one cycle when that happens...

Thank you so much: I'll change my decP and incP code accordingly and remove the check in loadConstant. May I ask, is this unstable state what the patent is referring to in relation to loadConstant when it says, "When used with the pointer in position 14, the instruction has no effect."? Is it really saying, "The pointer should never be 14, but don't worry about it if it is."? (I did wonder why it didn't mention 15.) [edited for spelling]