Reference Guide

RPL Programming 1-29
To recall the current flag states:
 Execute RCLF ( !°L %MODES% %FLAG% L%RCLF% ).
RCLF returns a list containing four 64-bit binary integers representing the current states of the lower and upper
groups of system and user flags:
{ # n
system-lower
# n
user-lower
# n
system-upper
# n
user-upper
}
To change the current flag states:
1. Enter the flag-state argument — see below
2. Execute STOF ( !°L %MODES% %FLAG% L%STOF% ).
STOF sets the current states of flags based on the flag-state argument:
# n
s
Changes the states of only the system flags.
{ # n
s-lower
# n
u-lower
# n
s-upper
# n
u-upper
} Changes the states of the system and user flags.
Example: The program PRESERVE on page 2-6 uses RCLF and STOF.
Using Subroutines
Because a program is itself an object, it can be used in another program as a subroutine. When program B is used by
program A, program A calls program B, and program B is a subroutine in program A.
Example: The program TORSA calculates the surface area of a torus of inner radius a and outer radius b. TORSA
is used as a subroutine in a second program TORSV, which calculates the volume of a torus.
The surface area and volume are calculated by
A π
2
b
2
a
2
–( )= V
1
4
---
π
2
b
2
a
2
–( ) b a–( )=
(The quantity in the second equation is the surface area of a torus calculated by TORSA.)
Here are the stack diagram and program listing for TORSA.
Level 2 Level 1
→
Level 1
a b
→
surface area
π
2
b
2
a
2
–( )