HP-35’s CHS behavior

[teenix]

(08-16-2019 08:19 PM)Matt Agajanian Wrote:  Actually, what I’m asking is this:

On the HP-35 page here on MoHPC, there is a paragraph about the CHS operation.

The explanation given there is a bit hard to follow. If I could see some examples of what the paragraph is explaining, I could understand how CHS affects the stack, and how the placement of CHS affects number entry and the stack.

In short, I’m just asking for some examples of what the paragraph is explaining.

(Lengthy reply)

HP35

Press...
3 <- starts number entry mode
3
CHS
Enter <- stops number entry mode

X = -33
Y = -33
Z = 0
T = 0

Press...
CHS
<- the user probably just wanted to change to +33

X = 33 <- which it did
Y = -33
Z = 0
T = 0

but number entry mode was stopped so CHS starts number entry mode again but the new entry will be negative

Press...
4

X = -4 <- the -4 was confusing
Y = -33
Z = 0
T = 0


Probably, the display should have been....

CHS
X = -0
Y = -33
Z = 0
T = 0

Press 4
X = -4 <- as expected
Y = -33
Z = 0
T = 0


On the later HP 67...

Press...
3
3
CHS
Enter

X = -33
Y = -33
Z = 0
T = 0

Press...
CHS

X = 33
Y = -33
Z = 0
T = 0

Press...
4

X = 4 <- this behaviour was more correct
Y = -33
Z = 0
T = 0

Back on the 35...
Continuous number entry

X = 0
Y = 0
Z = 0
T = 0

Press...
4

X = 4
Y = 0
Z = 0
T = 0

Press...
4

X = 44
Y = 0
Z = 0
T = 0

Press...
CHS

X = -44
Y = 0
Z = 0
T = 0

Press...
CHS

X = 44
Y = 0
Z = 0
T = 0

Press...
4

X = 444
Y = 0
Z = 0
T = 0

Press...
CHS

X = -444
Y = 0
Z = 0
T = 0

Press...
ENTER

X = -444
Y = -444
Z = 0
T = 0

cheers

Tony