sdcc/src/z80/support.c

   1 /** @file z80/support.c
   2  */
   3 #include "z80.h"
   4 #include <math.h>
   5
   6 int
   7 convertFloat (Z80_FLOAT * f, double native)
   8 {
   9   unsigned long mantissa, exponent;
  10   double f2;
  11   wassert (f);
  12   if (native != 0)
  13     {
  14       f2 = floor (log (fabs (native)) / log (2)) + 1;
  15       mantissa = (unsigned long) (0x1000000 * fabs (native) / exp (f2 * log (2))) ;
  16       mantissa &= 0xffffff;
  17       exponent = (unsigned long) (f2 + 0x40) ;
  18       if (native < 0)
  19         exponent |= 0x80;
  20     }
  21   else
  22     {
  23       mantissa = 0;
  24       exponent = 0;
  25     }
  26
  27   f->w[0] = (WORD) mantissa;
  28   f->w[1] = (BYTE) (mantissa >> 16);
  29   f->w[1] |= exponent << 8;
  30
  31   f->b[0] = (BYTE) f->w[0];
  32   f->b[1] = (BYTE) (f->w[0] >> 8);
  33   f->b[2] = (BYTE) f->w[1];
  34   f->b[3] = (BYTE) (f->w[1] >> 8);
  35
  36   return 0;
  37 }