Different speeds for HP-41CX and HP-41CV

[hth]

(12-14-2016 08:04 PM)aurelio Wrote:  and if you try with the 41C, I think is faster

see here

and from that site:


"HP-41 2.8 HP-41CV 2. 5 HP-41CX 2.6 HP-41CL (50x) 64.7

It is not quite clear why the 41C is faster than the CV and CX. Maybe branching to labels takes longer if more memory has to be searched for a label."

There should not be a much of a difference.

The clock speed may differ slightly due to tolerances in the components. If a program is not packed, there may be differences due to invisible nulls. If one had compiled branches and the other did not, there may be differences (run twice to get it right). Program alignment (on register boundaries) may have some very minor influence, and so may different ROM versions.

Otherwise they execute the same instructions internally. Poll vectors are not normally called during program execution unless there are attached peripherals that wants attention.

The amount of available memory does not affect the speed of program runs at. It compiles label distances, and searching for a label takes place within the current program,.

There are some instructions that depend on the outside environment and may differ, like PSE and XEQ/GTO global labels and XROM calls, but no such instruction is used in the test program.

Håkan