************************************************************************
**            Written by Dino Papararo            09-Nov-1998
**
**  FUNCTION
**
**    MandReal -- perform Z = Z^2 + C iteration.
**
**  SYNOPSIS
**
**    WORD Mand (WORD Iterations,long double Cre,long double Cim)
**
**
**  DESCRIPTION
**
**  C equivalent function:
**
**      ***************************************************************
**      *WORD Mand (WORD Iterazioni,long double Cre,long double Cim)***
**      *{                                                          ***
**      *register long double zr,zi,zi2,Dist,MaxDist;               ***
**      *                                                           ***
**      *  zi = Cim;                                                ***
**      *                                                           ***
**      *  zr = Cre;                                                ***
**      *                                                           ***
**      *  MaxDist = 4.0;                                           ***
**      *                                                           ***
**      *  do {                                                     ***
**      *       zi2 = zi * zi;                                      ***
**      *                                                           ***
**      *       zi = zr + zr;                                       ***
**      *                                                           ***
**      *       Dist = zr * zr + zi2;                               ***
**      *                                                           ***
**      *       zr = zr * zr - zi2;                                 ***
**      *                                                           ***
**      *       zi = zi * zi + Cim;                                 ***
**      *                                                           ***
**      *       zr = zr + Cre;                                      ***
**      *                                                           ***
**      *     } while (-- Iterazioni && (MaxDist > Dist));          ***
**      *                                                           ***
**      *  if (Iterazioni <= 0) Iterazioni = 1;                     ***
**      *                                                           ***
**      *  return Iterazioni;                                       ***
**      *}                                                          ***
**      ***************************************************************
**
**  This function tests if a point belongs or not at mandelbrot's set
**
**  Optimized for pipelines of PPC coprocessors
**
**  NOTICE: ALL VARIABLES ARE INTO REGISTERS FOR FULL SPEEEED
**          THE REGISTERS ARE CHOOSEN TO RESPECT THE WarpOs V14 STANDARD CONTEXT SWITCHES
**          A JULIA ROUTINE COULD BE WRITTEN FOLLOWING THE MANDELBROT FUNCTION EXAMPLE.
**          -----------------THIS CODE IS UNTESTED !!!!----------------
**
**  r3:Iterations
**  f0:Cre f1:Cim f2:Zr f3:Zi f4:Zi2 f5:Dist f6:MaxDist

                include powerpc/ppcmacros.i

                XDEF _MandPPC_FPU

                section code
                cpu POWERPC

_MandPPC_FPU:

                 prolog            ; start

                 fmr   f3,f1       ; zi   = cim
                 fmr   f2,f0       ; zr   = cre
                 lf    f7,Four     ; maxdist = 4.0
                 mtctr r3          ; load reg counter with iterations

.Loop
                 fmul  f4,f3,f3    ; zi2 = zi * zi
                 fadd  f3,f2,f2    ; zi = 2 * zr
                 fmadd f5,f2,f2,f4 ; dist = zr * zr + zi2
                 fmsub f2,f2,f2,f4 ; zr [new] = zr * zr - zi2
                 fmadd f3,f3,f3,f1 ; zi = zi * zi + Cim
                 fadd  f2,f2,f0    ; zr [new] = zr + Cre
                 fcmpu f5,f6       ; if maxdist > dist  and
                 bdnzf GT,.Loop    ; if iterations != 0 loop

.End

                 mfctr r3          ; store iterations from reg counter
                 ble   .Jump       ; if iterations <= 0
                 li    r3,1        ; Iterations = 1
.Jump

                 epilog            ; end

                 section data

Four             dc.d  4.0