PLE5P8                                        PLE DESIGN SPECIFICATION
P5025                                          PETER WITTFOTH 06/02/84
PERIMETER OF A CIRCLE LOOK-UP TABLE
MMI GMBH MUNICH
.ADD R0 R1 R2 R3 R4
.DAT P0 P1 P2 P3 P4 P5 P6 P7


P0 =     /R1* R2*/R3*/R4      ; COMPUTE DIGIT FOR 2EXP0 (1) (LSB)
   + /R0*/R1* R2*    /R4
   +      R1* R2*     R4
   +      R1*/R2*/R3
   +  R0*/R1*/R2* R3
   + /R0* R1*/R2
   +      R1*/R2*    /R4
   +     /R1*/R2*     R4

P1 =  R0*    /R2*/R3          ; COMPUTE DIGIT FOR 2EXP1 (2)
   + /R0* R1* R2*/R3
   + /R0*    /R2* R3
   +  R0*     R2* R3
   + /R0*     R2*/R3* R4
   +  R0*/R1* R2*    /R4
   +     /R1* R2* R3*/R4
   +  R0* R1*     R3* R4

P2 =  R0*/R1*    /R3*/R4      ; COMPUTE DIGIT FOR 2EXP2 (4)
   +  R0* R1*/R2*/R3* R4
   + /R0* R1* R2* R3* R4
   + /R0* R1*/R2*    /R4
   +      R1* R2*/R3*/R4
   +  R0* R1*     R3*/R4
   + /R0*/R1*/R2*     R4
   +     /R1* R2*/R3* R4
   +  R0*/R1*     R3* R4

P3 = /R0* R1*/R2*    /R4      ; COMPUTE DIGIT FOR 2EXP3 (8)
   +  R0*/R1*/R2* R3
   +  R0*/R1*/R2*     R4
   +  R0*    /R2* R3* R4
   +  R0*     R2*/R3*/R4
   + /R0*     R2* R3*/R4
   +      R1* R2* R3*/R4
   + /R0*     R2*/R3* R4
   +      R1* R2*/R3* R4
   + /R0* R1* R2*     R4
   + /R0*/R1* R2*/R3

P4 =  R0* R1*/R2*/R3          ; COMPUTE DIGIT FOR 2EXP4 (16)
   +      R1*/R2*/R3* R4
   + /R0*/R1* R2*/R3
   +  R0*/R1* R2*    /R4
   +     /R1*/R2* R3
   + /R0* R1*     R3*/R4
   +      R1* R2* R3*/R4
   +     /R1*     R3* R4
   + /R0*     R2* R3* R4

P5 =      R1* R2*/R3*/R4      ; COMPUTE DIGIT FOR 2EXP5 (32)
   +     /R1*/R2* R3*/R4
   +         /R2*/R3* R4
   +      R1*/R2*     R4
   +     /R1* R2* R3* R4
   + /R0* R1*/R2* R3
   + /R0*/R1* R2*     R4
   + /R0*     R2* R3* R4

P6 =  R0* R1*     R3*/R4      ; COMPUTE DIGIT FOR 2EXP6 (64)
   + /R0*/R1*    /R3* R4
   +          R2* R3*/R4
   +         /R2*/R3* R4
   +  R0* R1* R2* R3

P7 =  R0*     R2*     R4      ; COMPUTE DIGIT FOR 2EXP7 (128) (MSB)
   +      R1* R2*     R4
   +              R3* R4


FUNCTION TABLE

;---RADIUS----    -------PERIMETER-------
;   INTEGER       MSB     INTEGER     LSB               PERIMETER OF A CIRCLE
R4 R3 R2 R1 R0    P7 P6 P5 P4 P3 P2 P1 P0    ;RADIUS     LOOK-UP  CALCULATED
------------------------------------------------------------------------------
L  L  L  L  L     L  L  L  L  L  L  L  L         0           0        0.0
L  L  L  L  H     L  L  L  L  L  H  H  L         1           6        6.3
L  L  L  H  L     L  L  L  L  H  H  L  H         2          13       12.6
L  L  L  H  H     L  L  L  H  L  L  H  H         3          19       18.8
L  L  H  L  L     L  L  L  H  H  L  L  H         4          25       25.1
L  H  L  L  L     L  L  H  H  L  L  H  L         8          50       50.3
H  L  L  L  L     L  H  H  L  L  H  L  H        16         101      100.5
H  H  H  H  H     H  H  L  L  L  L  H  H        31         195      194.8
------------------------------------------------------------------------------


DESCRIPTION

THIS EXAMPLE ILLUSTRATES HOW TO IMPLEMENT A LOOK-UP TABLE IN A PLE5P8 FOR THE
PERIMETER OF A CIRCLE AS A FUNCTION OF THE RADIUS.  THE INPUT PINS (R4-R0),
WHICH REPRESENT THE RADIUS OF A CIRCLE, ARE MULTIPLIED BY 2 TIMES PI IN ORDER
TO CALCULATE THE PERIMETER OF A CIRCLE (P7-P0).  THIS LOOK-UP TABLE IS VALID
FOR RADII BETWEEN 0 AND 31.  A PLE8P8 SHOULD BE USED INSTEAD IF A LARGER
RADIUS RANGE (BETWEEN 0 AND 81) IS REQUIRED.

P = 2*PI*R     WHERE P  = PERIMETER OF THE CIRCLE
                     PI = 3.1415
                     R  = RADIUS OF THE CIRCLE (BETWEEN 0 AND 31)

EXAMPLE:  FOR R = 3, P = 2*PI*3 = 19
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