frct2flt.c

dsPIC30F_DSP算法库

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/* Local headers. */
#include "testing.h"				/* testing interface */

/*...........................................................................*/


float Fract2Float (			/* Converts fractional into float */
   fractional aVal			/* fract value in range {-1, 1-2^-15} */
) {

#if	DATA_TYPE==FRACTIONAL		/* [ */

   /* Local declarations. */
   double scale = pow (2.0, -15.0);		/* 2^(-15) */
   long int fullRange = 1L<<16;			/* 2^(16) */
   long int halfRange = 1L<<15;			/* 2^(15) */
   double decimalVal = 0.0;

   /* Convert. */
   if (aVal >= halfRange) {
      aVal -= fullRange;
   }
   decimalVal = ((double) aVal)*scale;

   /* Return decimal value in floating point. */
   return ((float) decimalVal);

#else	/* ] [ */

   /* Return input value in floating point. */
   return ((float) aVal);

#endif	/* ] */

} /* end of Fract2Float */

/*...........................................................................*/

/***************************************************************************/
/* EOF */