BASIC-MTHPAK

* NAME BASIC-MTHPAK DOC. 70181832000 REV. A PAGE 46

1597 * 1598 * 1599 * SINE FUNCTION ROUTINE 1600 * 1601 * CALLING SEQUENCE: 1602 * 1603 * JST SINF 1604 * DAC ARG POINTER TO THE ARGUMENT 1605 * ......RETURN SINE OF THE ARGUMENT IN THE A AND B REGIS- 1606 * TERS 1607 * 1608 * 1609 * THE ARGUMENT IS LOADED AND DIVIDED BY 2*PI TO CONVERT RADIANS 1610 * TO CIRCLE REVOLUTIONS. THE INTEGRAL PART OF THE RESULT IS DIS 1611 * CARDED SINCE SIN(X)=SIN(X+2*PI). THE FRACTIONAL PART OF THE RESULT 1612 * IS REDUCED TO AN ANGLE IN THE FIRST AND FOURTH QUADRANT 1613 * (-1/4<=F.P.<=1/4), USING THE IDENTIT1ES: SIN(X)=SINC(X-2*PI) AND 1614 * SIN(X)=SIN(PI-X). THE REDUCED FRACTIONAL PART IS SAVED AND THEN 1615 * SQUARED. THE POLYNOMIAL IS EVALUATED IN THE REDUCED FRACTIONAL 1616 * PART SQUARED WITH IHE FOLLOWING COEFFIECIENTS C0=6.283185, 1617 * C1=41.34168, C2=81.60223, C3=-76.57498, C4=39.701067. THE POLY- 1618 * NOMIAL RESULT IS MULTIPLIED BY THE REDUCED FRACTIONAL PART TO OB- 1619 * TAIN THE FUNCTION RESULT. 1620 * 1621 * 1622 01303 0 000000 SINF DAC ** ENTRY 1623 01304 0 02 01303 LDA SINF 1624 01305 0 10 00070 JST LARG LOAD THE ARGUMENT 1625 01306 0 10 00361 JST D$22 DIVIDE IT BY 2*PI 1626 01307 0 001350 DAC TWPI 1627 01310 0 10 00104 JST H$22 SAVE THE RESULT 1628 01311 0 001221 DAC Z0 1629 01312 0 10 00651 JST INTF TAKE THE GREATEST INTEGER 1630 01313 0 001221 DAC Z0 FUNCTION 1631 01314 0 10 00277 JST S$22 SUBTRACT TO FIND NEGATIVE 1632 01315 0 001221 DAC Z0 FRACTIONAL PART 1633 01316 0 10 00122 JST N$22 TWO'S COMPLIMENT IT 1634 01317 0 10 00104 JST H$22 SAVE FRACTIONAL PART AS Z2 1635 01320 0 001170 DAC Z2 1636 01321 0 10 00277 JST S$22 SUBTRACT 1/4 TO TEST WHETHER 1637 01322 0 001366 DAC FFRH ANGLE IS IN FIRST QUADRANT 1638 01323 100400 SPL 1639 01324 0 01 01345 JMP SN02 JUMP TO RELOAD THE FRACTIONAL PART 1640 01325 0 10 00277 JST S$22 SUBTRACT 1/2 FROM RESULT TO 1641 01326 0 001370 DAC FHLF TEST WHETHER IT'S IN FOURTH QUADRANT 1642 01327 100400 SPL IF IT IS SKIP 1643 01330 0 10 00122 JST N$22 IF NOT, COMPLIMENT 1644 01331 0 10 00277 JST S$22 SUBTRACT 1/4 1645 01332 0 001366 DAC FFRH 1646 01333 0 10 00104 JST H$22 SAVE THE RESULT AS THE REDUCED ARGUMENT