A comment on index register allocation

Y = XI*X4 -k SIN (X3,X4) $IBFTC MAIN (.'OMPIA';X FCN,XI,X2,X3,X4 REAl, y(2),XXi(2),XX2(2),xxa(2),XX4(2) EQUI VALENCI'3 (Y,FCN),(X1,XXI),(X2,XX2),(X3, l XXa),(X4,XX4) (3 INPUT ()F I~EAL NUMBERS TO XX1, XX2, XX3 and C X X,I ASSUMED. XX~(2) .... 1.0 XX2(2) = 0.0 XX3(2) ..... 0,0 XX4('2) .... 0.0 FCN ,.' XI*X2 -+. SIN(X3*X4) C NOW Y(1) .... XXl,XX2 --k SIN(XXa,Xx4) C AND Y(2) .... 1 )Y(I)/DXXI. XXI(2) .... 0,0 XX3(2) = 1.