[HP 35s] Stepping-Preview after INPUT instruction

[gaindred]

Hello

If stepping through a program and holding the arrow-down-key, the next line to execute is shown.
If I hit an INPUT instruction and want to step to the next instruction, holding the arrow-down-key does not show me the program line. While releasing the key the instruction is executed. Actually I cannot preview the first program line after an INPUT instruction.

What is my fault? Is this an issue (couldn't find it in the bug list)?

My workaround is to insert a "nop"-instruction after each INPUT (e.g. PSE). So I can see the first meaningful line while stepping at least.

Thanks in advance!
Sven

[Dieter]

(06-01-2016 11:36 AM)gaindred Wrote:  If I hit an INPUT instruction and want to step to the next instruction, holding the arrow-down-key does not show me the program line. While releasing the key the instruction is executed. Actually I cannot preview the first program line after an INPUT instruction.

I do not think this a bug, it's just a ..."special feature". ;-)

During INPUT the 35s is in a different state than normal. The current value of the prompted variable is displayed and stack lift is disabled so that a new user entry overwrites the value in the display. You can even do calculations while the prompt in the upper line remains active. At this point the arrow down key obviously does not work as usual.

But there's a simple workaround. No need to insert meaningless instructions in your programs. Simply cancel the pending INPUT with the [C] key before entering something (or continuing without input - this works as well). After this pressing the arrow down key displays the next step, as usual.

Dieter

[gaindred]

(06-01-2016 12:32 PM)Dieter Wrote:  ...(or continuing without input - this works as well)...

This doesn't work on my 35s. Also in this case I don't get the "preview".

(06-01-2016 12:32 PM)Dieter Wrote:  Simply cancel the pending INPUT with the [C] key before entering something...

A modification of this works for me: at first I cancel the INPUT and peek the next instruction as you said. Then I step back (arrow-up-key) to the INPUT, step forward, make the real input and execute the following instruction.

It's a little tricky, but OK for testing.


Thank you!
Sven


Edit: No, this does not work in all cases, because the peeked instruction is executed and the result may be corrupted (e.g. if the next instruction is a store arithmetic operation).