HP 35s Manual

hp calculators
HP 35s Converting programs
to line number addressing
Programming the HP 35s
Using line numbers rather than labels
Example

hp calculators
HP 35s Converting programs to line number addressing
hp calculators - 2 - HP 35s Converting programs to line number addressing - Version 1.0
Programming the HP 35s
Doing a simple calculation once on the HP 35s is easy. Doing the same calculation many times, or doing a complicated
calculation, takes longer. It can be better to store all the steps needed for the calculation in a program. A program is a
set of instructions, stored all together. Once it is written, it can be tested to see if it works correctly. Then it can be used
many times, without the need to press every key of the calculation each time.
A simple program is just a set of keystrokes stored so that they can be carried out with one key. The HP 35s provides
many commands to let programs do more, for example stop and ask for input, or show an intermediate result.
This training aid concentrates on converting programs originally written using labels, such as programs written for the
HP33s, to using line number addressing, as is available on the HP 35s calculator.
Converting programs from labels to line numbers
The HP 35s has 26 labels for use to define programs or transfers to locations within programs. Unlike the HP 33s, the
HP 35s also includes the ability to transfer execution to specific line numbers within one of the 26 labels. This allows for
a much greater utilization of program memory without using labels excessively.
Suppose you have the program below and wish to convert it to the HP35s. This program will pause to display the
intermediate values, given a whole number input, as it performs the steps involved in Ulam’s Conjecture. Will the number
eventually converge to one or not? (Note: There has been absolutely no attempt to optimize this program!)
B011 RCL A
B012 3
B013 x
B014 1
B015 +
C001 LBL C
C002 STO A
C003 GTO B
D001 LBL D
D002 RCL A
D003 2
D004 INT÷
D005 GTO C
Label Version
A001 LBL A
A002 STO A
B001 LBL B
B002 PSE
B003 1
B004 x=y?
B005 RTN
B006 x<>y
B007 2
B008 RMDR
B009 x=0?
B010 GTO D
Converting on paper. Given the initial listing, the first suggestion is to make a note next to the first step following each
LBL instruction after the initial label that starts the routine. These would be the PSE after LBL B, the STO A after LBL C,
the RCL A after LBL D. Beside each of these steps, write B, C, and D. These will become the steps that line number
GTOs and XEQs will reference. In the listing below, these steps are BOLD.

hp calculators
HP 35s Converting programs to line number addressing
hp calculators - 3 - HP 35s Converting programs to line number addressing - Version 1.0
Now, write the program down again, but this time leave out all LBL instructions – but put the LBL letter next
to the instruction that follows the now deleted label. Also leave in the GTO (or XEQ) instructions with the
labels originally referenced. This may make it easier to replace them with the proper line number addresses.
With Line Numbers
LBL A
STO A
B PSE
1
x=y?
RTN
X<>Y
2
RMDR
x=0?
GTO D
RCL A
3
X
1
+
C STO A
GTO B
D RCL A
2
INT÷
GTO C
Now begin numbering the lines starting with A001. When you get to a line with a letter next to it, find the
GTO or XEQ instruction with that same letter. Change that GTO or XEQ instruction to point to the line
number of the instruction that had the letter next to it. Line A003 is the first one encountered.
With Line Numbers
A001 LBL A
A002 STO A
B PSE
1
x=y?
RTN
X<>Y
2
RMDR
x=0?
GTO D
RCL A
3
X
1
+
C STO A
GTO A003
**Changed**
D RCL A
2
INT÷
GTO C
Label Version
A001 LBL A
A002 STO A
B001 LBL B
B002 PSE
B003 1
B004 x=y?
B005 RTN
B006 x<>y
B007 2
B008 RMDR
B009 x=0?
B010 GTO D
B011 RCL A
B012 3
B013 x
B014 1
B015 +
C001 LBL C
C002 STO A
C003 GTO B
D001 LBL D
D002 RCL A
D003 2
D004 INT÷
D005 GTO C

hp calculators
HP 35s Converting programs to line number addressing
hp calculators - 4 - HP 35s Converting programs to line number addressing - Version 1.0
Continue working through the program in this manner. Line A017 is the next one. Then line A019.
With Line Numbers
A001 LBL A
A002 STO A
A003 PSE
A004 1
A005 x=y?
A006 RTN
A007 X<>Y
A008 2
A009 RMDR
A010 x=0?
A011 GTO D
A012 RCL A
A013 3
A014 X
A015 1
A016 +
A017 STO A
GTO A003
D RCL A
2
INT÷
GTO A017
**Changed**
With Line Numbers
A001 LBL A
A002 STO A
A003 PSE
A004 1
A005 x=y?
A006 RTN
A007 X<>Y
A008 2
A009 RMDR
A010 x=0?
A011 GTO A019
**Changed**
A012 RCL A
A013 3
A014 X
A015 1
A016 +
A017 STO A
A018 GTO A003
A019 RCL A
2
INT÷
GTO A017
The final version of the program would look like this:
With Line Numbers
A001 LBL A
A002 STO A
A003 PSE
A004 1
A005 x=y?
A006 RTN
A007 X<>Y
A008 2
A009 RMDR
A010 x=0?
A011 GTO A019
A012 RCL A
A013 3
A014 X
A015 1
A016 +
A017 STO A
A018 GTO A003
A019 RCL A
A020 2
A021 INT÷
A022 GTO A017
Conclusion. While there are many ways of converting programs containing labels to use line numbers, this is one
example. Line number addressing provides many benefits on the HP 35s.