> Hi all !
> Where could I get a 16 bit square root routine for PIC 17C43 ?
>
> Juha


The following code takes the sqrare root of a 16 bit number and returns a
fixed point result of 8 bits integer and 8 bits fraction. The main loop of
the
routine generates one bit fro every interation. There are square root
routines
that converge in fewer interations.

Walter Banks

#pragma has PIC16;
#pragma has MUL;


long SQRT (long l)
 /*
    Square root V1.0.

    Hayward/Banks approximation.

    This routine generates a square root to
    16 bit resolution taking a 16 bit argument
    normalizing the argument and returning a 16 bit
    real number that consists of 8 bits interger and
    8 bit fractional parts. The MS8bits are the interger
    part.

      i i i i  i i i i . f f f f  f f f f
      | | | |  | | | |   | | | |  | | | |
    128 |32 |  8 4 2 1  .5 | | |  | | |  .00390625
       64  16           .25  | |  | |  --.0078125
                        .125-  |  |  ----.015625
                        .0625--    ------.03125


   These routines may be adapted for any purpose when
   used with the MPC Code Development system.  No
   warranty is implied or given as to their usability
   for any purpose.

        (c) Copyright 1994
        Byte Craft Limited
        Waterloo, Ontario
        Canada N2J 4E4
        (519) 888-6911

        Gordon Hayward / Walter Banks
 */

  {
    unsigned int n,j,k;
    unsigned long t @ 0x18;  // Multiply result
    n = 0;
    while( (l & 0xc000) == 0)
     {
       n++;
       l <<= 2;
     }
    for (j = 0, k = 0x80; k != 0; k >>=1)
     {
       j = j | k;
       t = j * j;
       if (t > l) j = j & (~k);
     }
    t = j;
    return (t << (8-n));
  }

 unsigned long result;
 unsigned int int_part, frac_part;
 void main(void)
  {
    result = SQRT(6000);
    int_part  = result >> 8;
    frac_part = result & 0xff;
  }