cplxdiv.asm

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;
; CPLXDIV       : complex divide
;

.8087

include struct.inc
include mdef.inc

        modstart        cplxdiv


; Complex division
;    (a,b)/(c,d) = ((a,b)*(c,-d))/(c**2+d**2)

        xdefp   CplxDivide
defp    CplxDivide
        fld     st(0)                   ; compute c*c + d*d
        fmul    st(0),st(0)             ; ...
        fld     st(2)                   ; ...
        fmul    st(0),st(0)             ; ...
        faddp   st(1),st(0)             ; ...
        fdiv    st(3),st(0)             ; compute a/(c*c+d*d)
        fdivp   st(4),st(0)             ; compute b/(c*c+d*d)
        fld     st(2)                   ; compute ad/(c*c+d*d)
        fmul    st(0),st(2)             ; ...
        fxch    st(4)                   ; ...
        fmul    st(2),st(0)             ; compute bd/(c*c+d*d)
        fmul    st(0),st(1)             ; compute bc/(c*c+d*d)
        fsubrp  st(4),st(0)             ; compute imaginary part
        fmulp   st(2),st(0)             ; compute ac/(c*c+d*d)
        faddp   st(1),st(0)             ; compute real part
        ret
endproc CplxDivide

        endmod
        end