56-bit representation of numbers vs. what is displayed

[brianrhill]

Something I am confused about is how the HP-35 decides whether to display

1.23 45
vs
12.3 44

You will find that you can enter both of these (in the obvious way) and the display preserves what you entered even though these are two ways of writing the same number.

In fact you can also enter

1.23000 45

which is yet another way of expressing the same number.

If I understand correctly, the 56-bit C-register (also known as the X register) is accumulating the value as it is entered. Where is the additional information stored that the display is relying on to distinguish between and maintain—even after hitting Enter—these various different visual representations of the number?

Of course this is all in the microcode for the HP-35 and HP-45, but perhaps someone can explain it plainly for those who haven't learned to read the microcode.

Thanks!

~Brian Hill

PS: Many thanks to the people that restored Jacques Laporte's site (http://home.citycable.ch/pierrefleur/Jac...index.html) and I am also grateful to Germaine Laporte for authorizing it.