#include <math.h>

/* VAX float representation:
**
** bit:  0                             31
**       +--------------+-+------+------+
**       |   FRACTION   |S|  EXP | FRAC |
**       +--------------+-+------+------+
**
** The exponent is stored in binary 128 excess notation.
** The fraction is a 24-bit normalized fraction with the most significant bit
**   not stored.  If the exponent is not 0, this bit is assumed to be 1.  A
**   number with sign 0 and exponent 0 is assumed to be 0. in value.
*/

void vaxfloat(int *val,float *rval,int num)
{
/* val  is the first address of a block of integers containing the
**      representations of the VAX floats
** rval is the first address of a block of floats in native format created from
**      the VAX representations
** num  is the number of VAX representations to convert to native format
*/

  int  n,sign,exp,fr[2];

  for (n=0; n < num; n++) {
/* unpack sign, exponent, and fraction */
    gbyte32(&val[n],&sign,16,1);
    gbyte32(&val[n],&exp,17,8);
    if (exp == 0)
	rval[n]=0.;
    else {
	exp-=128;
	gbyte32(&val[n],&fr[0],0,16);
	gbyte32(&val[n],&fr[1],25,7);

/* reconstruct fraction */
	fr[0]+=((fr[1] << 16) | 0x800000);
	rval[n]=fr[0]*pow(2.,(float)(exp-24));
	if (sign == 1) rval[n]=-rval[n];
    }
  }
}