8 / VERSION 5A 4-27-77 PT
28 ATANC1, -15 /LOWER LIMIT TEST.
32 ATANC2, 0 /UPPER LIMIT TEST.
79 FLDA% BPATAN,1 /ADDR OF X
83 LDX -1,0 /REMEMBER SIGN
85 LDX 0,0 /SAVE THE SIGN.
86 FNEG /NEGATE THE FAC [ABS]
87 FSTA ATAN1 /AND STORE AWAY.
89 FSUB ATANC1 /TEST TO SEE IF TOO SMALL.
90 JLE ATANBG /IT IS. ATAN(X)=X
91 FSUB ATANC2 /TEST TO SEE IF TOO BIG.
93 FLDA F1ATAN /TO BIG. INVERT IT.
97 ATANLW, FCLA /CLEAR OUT TEMP.
99 FLDA ATAN1 /RECALL NUMBER.
100 FSUB ATANC3 /START THE KNOCKING OFF PROCESS.
101 JLT ATANNT /WRONG SECTOR.
102 FLDA ATANC4 /BOP UP ORIGINAL.
104 FLDA ATANCJ /GET MAGIC NUMBER.
111 ATANNT, FLDA ATAN1 /RECALL AND SQUARE IT.
113 FSTA ATAN4 /YET ANOTHER TEMP.