.TITLE ATAN .PSECT UTILS .GLOBL DATAN AC3 = %3 ;SYMBOL FOR FLT REG 3. ATAN:: ; CALCULATES THE ARCTANGENT OF THE DOUBLE-PRECISION ; ARGUMENT AT THE ADDRESS SUPPLIED IN THE CALL. PUTS THE ; RESULT AT THE ADDRESS SPECIFIED IN THE CALL AS THE ; DESTINATION ADDRESS. INTENDED TO BE INVOKED BY THE ; MACRO, "ATAN". MOV (R5)+,5$ ;GET SRC ADRS. SUB #8.,SP ;MAKE ROOM FOR AC3. STD AC3,(SP) ;SAVE AC3. JSR R5,DATAN ;CALC ARCTAN OF... BR 10$ ;RETURN POINT. 5$: .WORD 0 ;PLACE FOR ADDRESS OF SOURCE. 10$: STD AC3,@(R5)+ ;PUT RESULT INTO DEST. LDD (SP)+,AC3 ;RESTORE AC3. RTS R5 ;RETURN .END