HP-41CL Speed test vs. DM41X and DM42

[Sylvain Cote]

(10-17-2020 11:01 AM)grsbanks Wrote:  I don't know why because they're both running the original 41CX ROM.

All ROMs in a 41CL are stored in a speed modified padded 16 bits ROM format on which 2 bits (bit 13 & 12) are used to specified dynamic speed change when code is running.
So, even though TURBO50 (x50) is active, some MCode instructions will still be running at TURBOX (x1) for compatibility reason.

Extract taken from the 41CL User Manual:

Quote:The Turbo Functions give you control over the operating speed of the calculator.
The performance in Turbo mode is not linear, because some operations must always occur at normal speed.
For example, scanning the keyboard (which is done once per program line) always executes at normal speed.
Similarly, accessing the display for any reason always executes at normal speed.
All accesses of a physical Port occur at normal speed, along with a number of timing loops in the Operating System and Timer functions.

Turbo mode is explained in details in NEWT Microprocessor Technical Manual, pages 127 to 129.

Sylvain