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For example, ´b´A becomes ´bA, ´m´%
becomes ´m%, and O´# becomes O#.
The removal of the ´ is not ambiguous because the ´-shifted function
is the only logical one in these cases. The keycodes for such instructions do
not include the extraneous ´ even if you do key it in.
User Mode
User mode is a convenience to save keystrokes when addressing (calling
up) programs for execution. Pressing ´U will exchange the primary
functions and ´-shifted functions of the A through E keys only. In
User mode (USER annunciator displayed):
´ shift
Primary
| shift
Press | U again to deactivate User mode.
Polynomial Expressions and Horner's Method
Some expressions, such as polynomials, use the same variable several times
for their solution. For example, the expression
uses the variable x four different times. A program to solve such an
equation could repeatedly recall a stored copy of x from a storage register.
A shorter programming method, however, would be to use a stack which
has been filled with the constant (refer to Loading the Stack with a
Constant, page 41).
Horner's Method is a useful means of rearranging polynomial expressions to
cut calculation steps and calculation time. It is especially expedient in
_ and f, two rather long-running functions that use subroutines.
This method involves rewriting a polynomial expression in a nested fashion
to eliminate exponents greater than 1:
Section 6: Programming Basics
A
B
¤
'
2
x
LN
4
3
f(x) = Ax
+ Bx
4
3
Ax
+ Bx
+ Cx
3
2
(Ax
+ Bx
+ Cx + D)x + E
2
((Ax
+ Bx + C)x + D)x + E
(((Ax + B)x + C)x + D)x + E
C
D
@ y
LOG
2
+ Cx
+ Dx + E
2
+ Dx + E
79
E
∕
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