.TITLE ATAN   COMPUTE ARCTANGENT FOR REAL ARGUMENT
/COPYRIGHT 1970, DIGITAL EQUIPMENT CORP., MAYNARD, MASS.
/EDIT 1   10-22-70
       .GLOBL ATAN,.DA,.AG,.ED
/             CALLING SEQUENCE
/      JMS*   (ATAN)          SUBR CALL
/      JMP    .+2             SUBR RETURN
/      CAL/XCTADDR            ADDR OF ARGUMENT (XCT IF INDIRECT)
/
ATAN   CAL    0              /ENTRY-EXIT
       JMS*   .DA            /GET ARGUMENT (.DA)
       JMP    ATAN02
ATAN01 CAL    0              /ARGUMENT
ATAN02 JMS*   .AG            /LOAD REAL (.AG)
       .DSA   ATAN01+400000  / (ARG)
       JMS*   .ED            /COMPUTE ARCTANGENT (.ED)
       JMP*   ATAN           /EXIT
       .END