Automatic stack lift enable / disable

Discussion around the Swiss Micros DM42 calculator.
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Walter
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Automatic stack lift enable / disable

Post by Walter »

From another forum:
Thomas Okken wrote: On the HP-42S, R/S does not enable stack lift, neither when used to interrupt a running program nor when used to start or resume program execution.

The STOP command, in a program, does enable stack lift, though.
Is R/S one of the so-called neutral operations which don't change the stack-lift status? I don't find anything about this class of operations in the HP-42S manuals. Thanks in advance for enlightenment.

EDIT: Consequence: Does this apply to the DM42 as well?
DM42 SN: 00041 Beta
WP 43S running on this device

HP-35, HP-45, ..., HP-35S, WP 34S, WP 31S, DM16L
Thomas Okken
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Re: Automatic stack lift enable / disable

Post by Thomas Okken »

I don't know about "operations" -- R/S starts and stops program execution, without any side effects other than starting and stopping program execution, as far as I'm aware. But this does not apply to the STOP instruction, which R/S happens to insert if you press it in PRGM mode.

And yes, all of this applies to Free42 as well, and thus to the DM42, I would assume.
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Walter
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Re: Automatic stack lift enable / disable

Post by Walter »

Does R/S close input?
DM42 SN: 00041 Beta
WP 43S running on this device

HP-35, HP-45, ..., HP-35S, WP 34S, WP 31S, DM16L
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Re: Automatic stack lift enable / disable

Post by Thomas Okken »

You mean terminate number entry? If so, yes, just like on the 41, since they treat numbers as atomic entities inside programs rather than as a sequence of digits that are executed separately.
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Walter
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Re: Automatic stack lift enable / disable

Post by Walter »

Thomas Okken wrote:
Mon Nov 02, 2020 12:38 am
You mean terminate number entry? If so, yes, just like on the 41, since they treat numbers as atomic entities inside programs rather than as a sequence of digits that are executed separately.
Yes, I meant 'terminate number entry' = 'close (numeric) input'. As mentioned above, I couldn't find anything about it in the HP-42S manuals, neither in the OM nor the Programming Examples...

To make it crystal clear: If we'd have a code sniplet

Code: Select all

...
STOP
STOP
VIEW X
...
and key in after the first stop: 123 R/S 456 R/S then this program would display 456 on the DM42/HP-42S? Or 123456 instead?
DM42 SN: 00041 Beta
WP 43S running on this device

HP-35, HP-45, ..., HP-35S, WP 34S, WP 31S, DM16L
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Re: Automatic stack lift enable / disable

Post by Thomas Okken »

456. Number entry is terminated by everything except [0] through [9], [.], [E], [+/-], Shift, OFF (only Shift-EXIT or automatic power off; it is terminated by the OFF function), and [←].
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Walter
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Re: Automatic stack lift enable / disable

Post by Walter »

Thomas Okken wrote:
Mon Nov 02, 2020 11:53 am
456. Number entry is terminated by everything except [0] through [9], [.], [E], [+/-], Shift, OFF (only Shift-EXIT or automatic power off; it is terminated by the OFF function), and [←].
Thanks a lot! :D
DM42 SN: 00041 Beta
WP 43S running on this device

HP-35, HP-45, ..., HP-35S, WP 34S, WP 31S, DM16L
hth313
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Re: Automatic stack lift enable / disable

Post by hth313 »

You are confusing digit entry and stack lift flag enabled (push flag). They are two different things.

Digit entry is about pressing multiple keys to form a number. On the HP-41 it is always ended when you do something else than add or remove to the number being entered, except for pressing SHIFT or USER keys (which stays in digit entry).

Stack lift disable (called push flag internally) is whether the next number entry lifts the stack or not. ENTER and CLX disables it, some few operations are neutral and most enables it. This is documented in the manuals.
Last edited by hth313 on Tue Nov 03, 2020 11:43 pm, edited 1 time in total.
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Walter
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Re: Automatic stack lift enable / disable

Post by Walter »

hth313 wrote:
Tue Nov 03, 2020 5:20 pm
Stack lift disable (called push flag internally) is whether the next number entry lifts the stack or not. ENTER and CLX disables it, some few operations are neutral and most enables it. This is documented in the manuals.
We're talking about the HP-42S/DM42 here. Please tell me where in the manuals the neutral operations are documented.
DM42 SN: 00041 Beta
WP 43S running on this device

HP-35, HP-45, ..., HP-35S, WP 34S, WP 31S, DM16L
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