sw/os8/v3d/sources/fortran/all/csqrt.ra

   1 /
   2 /   C S Q R T
   3 /   - - - - -
   4 /
   5 / VERSION 5A 4-27-77  PT
   6 /
   7 /COMPLEX SQUARE ROOT ROUTINE
   8 /ENTER+ EXIT IN COMPLEX
   9 /Z=X+IX
  10 /
  11 /SQRT(Z)=SQRT(R)*COS(THETA)+SIN(THETA))
  12 /
  13 /R=SQRT(X*X+Y*Y)
  14 /THETA=ATAN2(Y/X)/2
  15 /
  16 /CALLS SQRT,ATAN2,SIN,COS
  17 /
  18         SECT    CSQRT
  19         JA      #CSQRT
  20         DPCHK
  21         TEXT    +CSQRT +
  22 CSQRTX, SETX    XR
  23         SETB    BP
  24         JA      .+3
  25 BP,     F 0.0
  26 XR,     F 0.0
  27 ARG,    F 0.0
  28         F 0.0
  29 THETA,  F 0.0
  30 FP2,    F 2.0
  31         ORG 10*3+BP
  32         FNOP
  33         JA      CSQRTX
  34         0
  35 RT,     JA      .
  36         BASE    0
  37 #CSQRT, STARTD
  38         FLDA    10*3
  39         FSTA    RT
  40         FLDA    0
  41         SETB    BP
  42         SETX    XR
  43         BASE    BP
  44         LDX     1,1
  45         FSTA    BP
  46         FLDA%   BP,1
  47         FSTA    BP
  48         STARTE
  49         FLDA%   BP
  50         FSTA    ARG
  51         STARTF
  52         EXTERN  ATAN2
  53         JSR     ATAN2           /ATAN(Y/X)
  54         JA      CSA
  55         JA      ARG+3
  56         JA      ARG
  57 CSA,    FDIV    FP2             /ATAN/2
  58         FSTA    THETA
  59         FLDA    ARG
  60         FMULM   ARG             /X*X
  61         FLDA    ARG+3
  62         FMUL    ARG+3           /Y*Y
  63         FADD    ARG             /X*X+Y*Y
  64         FSTA    ARG
  65         EXTERN  SQRT            /SQRT(X*X+Y*Y)
  66         JSR     SQRT
  67         JA      CSB
  68         JA      ARG
  69 CSB,    FSTA    ARG             /R
  70         EXTERN  SQRT
  71         JSR     SQRT
  72         JA      CSC
  73         JA      ARG             /SQRT(R)
  74 CSC,    FSTA    ARG             /SQRT(R)
  75         EXTERN  SIN
  76         JSR     SIN             /SIN(THETA/2)
  77         JA      CSD
  78         JA      THETA
  79 CSD,    FMUL    ARG             /*SQRT(X)
  80         FSTA    ARG+3
  81         EXTERN  COS
  82         JSR     COS             /COS(THETA/2)*SQRT(R)
  83         JA      CSE
  84         JA      THETA
  85 CSE,    FMUL    ARG
  86         FSTA    ARG
  87         STARTE
  88         FLDA    ARG
  89         FSTA    #CAC
  90         JA      RT
  91         EXTERN  #CAC
  92 \f