Radio Shack TRS-80 - Page 219

Exponentiation
Computes:
X
Y
(X to
the Y
power)
Input:
X,
%
If X is less than
zeso,
Y
must
be
an odd
integer
Output:
P
Also uses:
E,
L, A,
B, C
internally.
Value of X is changed.
Other
subroutines
required:
Log
and
Exponential
How
to call:
3012(9
Logarithms
(Natural
and
Common)
Computes:
LOG(X)
base e, and LOG{X) base
10
Input:
X
greater than or
equal to
zero
Output:
L is
natural
log (base e), X is
common log (base
10)
Also uses: A,B,C interally.
Value
of
X is changed.
Other subroutines
required:
None
How
to
call:
GOSUB 30190
Exponential
Computes:
EXP
(X)
(e
to the X power)
Input: X
Output:
E
Also
uses: L,A internally.
Value
of
X is
changed.
Other
subroutines required:
None
How
to
call:
GOSUB
30250
30000
END
30100 REM
*EXPONENTI ATION*
INPUT
X,Y
t
OUTPUT P
30110 REM ALSO
USES
E ,
L
,
A
,
B
, C
INTERNALLY
30120 P=l : E
=
2 j
IF
Y
=
T. RET.
30130 IF
(X<0)*( INT( Y)=Y1
T. P=l-2*Y+4*
INT[ Y/2
)
t
X
=
-X
33140 IF
XO0 T. GOS. 30190 t
X
=
Y*L
:
GOS. 30250
32150
P
=
P*E :
RET.
30000
END
30170
REM
*NATURAL & COMMON LOG*
INPUT
X. OUTPUT
L,X
30175
REM
OUTPUT
L IS NATURAL LOG,
OUTPUT
X
IS
COMMON
LOG
30180 REM ALSO
USES
A.B.C INTERNALLY
30190
E=0 :
IF
X<2 T. P. "LOG
UNDEFINED AT"
jX:STOP
30195
A=l i B
=
2 : C=.5
32200
IF
X>=A T. X=C*X : E
=
E
+
A
:
G. 30200
30205 IF X<C
T. X=B*X : E=E-A : G. 30205
30210 X=(X-
,707127)/{
X+ .707137
) : L
=
X*X
30215 L=C({
,598979*L+.
961471
)*L+2.88539)*X+E-.
5)*,
693147
30220 IF
ABS(LXlE-6
T. L
=
30225 X=L*.
4342945 :
RET.
30000
END
32240
REM
*
EXPONENT
I AL* INPUT X,
OUTPUT
E
30245
REM ALSO USES
L,A
INTERNALLY
32250 L=INT( 1 .
4427*X)+1 : IF L<127 T.
30265
32255 IF X>0 T.
P. "OVERFLOW
"
: STOP
30360 E=0 : RET.
30265 E=
.693147*L-X
: A= 1 . 3 29 B 8E- 3- I
. 4 1 3 1 6E-4 *E
30275 E=(((A-.
166665)*
E+.
5)*
E-1)*E+1 :
A=2
30280 IF L<=0
T. A=
.
5 i L=-L :
IF
L=0
T. RET.
30285
F. X=l
TO
L : E=A*E : N.
X
:
RET.
217