Testing various conditions with the HP10C/HP12C

[Namir]

The HP-12C and HP-10C have the same number of very limited conditional tests. The following should allow you to simulate some of the other missing tests.

NOTE: The symbols X' and Y' denote the original values of the X and Y registers.
These values may end up swapped in the Y and X stack registers! So write your code accordingly.
You may need to first use X<>Y to restore the original values of the stack registers.

Code:

1) x=0? 
SimpLe. It's built in.

2) X<=0? AND X>0?

0
X<>Y
X<=Y?
GTO Line n1  ---> X<=0
GTO Line n2  ---> X>0

3) X>=0? AND X<0?

0
X<=Y?
GTO Line n1  ---> X'>=0
GTO Line n2  ---> X'<0


4) X<=y? AND X<Y?

X<=Y? is built in.

X<>Y
X<=Y?
GTO Line n1  ---> X'>=Y'?
GTO Line n2  ---> X'<Y'?

5) X>Y? AND X=Y? AND X<Y?

X<=Y?
GTO Line n1
GTO Line n2  ---> X>Y?
Line n1: X<>Y
X<=Y?
GTO Line n3 ---> X'=Y'?
GTO Line n4 ---> X'<Y'?

6) X=0? AND X<0? AND X>0?

first filtier out X = 0
X=0?
GTO Line n1
0
X<=Y?
GTO Line n2 ---> X'>0?
GTO Line n3 ---> X'<0?

Namir