HP-35s Roll down question

[Kevin Braun]

Hi Experts,

I am a new owner of an HP-35s and am entering a Moon Lander program:
http://www.hpmuseum.org/software/35moonla.htm

and line: C027 Rv

has me a bit confused, When I am entering the line and I press Rv, I get:
X Y Z T
0.0

And I am not clear on how to proceed. Would someone mind pointing me in the right direction?

Thank you.
KB

[Dieter]

(03-04-2019 12:43 AM)Kevin Braun Wrote:  I am a new owner of an HP-35s and am entering a Moon Lander program:
http://www.hpmuseum.org/software/35moonla.htm

and line: C027 Rv

has me a bit confused, When I am entering the line and I press Rv, I get:
X Y Z T
0.0

First of all, just to be sure: you do not have to enter "Rv" (letters R and V). "Rv" is a common way of writing R↓, the roll down key. So you do not press EQN and enter "R" and "V". Just press the [R↓] key instead. Edit: looking at the subject line you obviously already knew that. #-)

What you described happens in equation mode, i.e. you have pressed the EQN key before. In this case R↓ lets you select one of the displayed registers X...T. You will see "C027 _" and the EQN annunciator on top of the display is on.

Simply delete that line so that you see C026 STO+V again. Then press the [R↓] key. This will insert a R↓ command. That's all.

Looking at the program I'd say that the R↓ line is not even required:

Code:

.... ...
C023 RCL V
C024 +
C025 STO H
C026 RCL A
C027 STO+ V
C028 1
C029 STO+ T
C030 VIEW T
C031 PSE
C032 GTO M001

This should work as well.

Dieter

[Kevin Braun]

Thank you Dieter, I see now. One more for you, line:
C020 /

which key is the "/"

Thank you again.

KB

[Dieter]

(03-04-2019 04:17 PM)Kevin Braun Wrote:  C020 /
which key is the "/"

That's the divide key [÷]. Since there is no "÷" on a standard keyboard, division is usually written with the more common "/" character. For the same reason multiplication is usually expressed as "*" instead of "×" (but not in this program).

Dieter

[Kevin Braun]

Excellent Dieter, thank you yet again. I am thinking about posting this program in this way to my website, so that other beginners may have an easier time, what do you think? (of course with credit to the programmer, that I did not write it, only annotate it)
(image attached)

[Dieter]

(03-05-2019 01:50 PM)Kevin Braun Wrote:  I am thinking about posting this program in this way to my website, so that other beginners may have an easier time, what do you think? (of course with credit to the programmer, that I did not write it, only annotate it)

I am not sure if credits are sufficient. To be sure you should ask the original author for permission to redistribute his program on your website.

The image with the listing looks quite nice.

Dieter