HP HP-16C - Section 7: Programming Basics; Data Input; Prior Entry

74 Section 7: Programming Basics
Example: The body of the concatenation program is listed below.
Assuming that two separate numbers are given in the X- and Y-
registers, program lines 002 to 008 below will concatenate those
two 16-bit words into one 32-bit word. The word initially in the
X-register will become the most significant bits of the result.
Keystrokes Display
002- 23
2 003- 2 Doubles the word size
0 004- 0 from 16 to 32, providing
005- 42 44 16 extra bits to the left of
the numbersin X and Y.
(9][LSTx] 006- 4336 Brings back word size
(32).
007- 42 b Computes one-half of
word size (16).
008- 42 E Shifts number left 16
bits.
009- 4240 ORoperation here
concatenates the
contentsof X and Y.
Ending a Program.
e Theinstruction [9][RTN](return) will end a program, return to
line 000, and halt.* This instruction can be omitted if the
program is the last one in memory, since the end of the
program memory contains an automatic [RTN].
e The instruction (run/stop) will stop a program without
moving the line position to line 000.
Keystrokes Display
(9][RTN] 010- 4321 Optionalifthisisthe
last program in memory.
* Except when a subroutine return is pending, as discussed in section 9, page 94.