deterministic float prng using an xorshift

//32-bit xorshift lfsr
int lfsr32(){
  static int last=0xfeedbac;//k (starting number must be non-zero)
  int current=last ^ (last<<13);
  current^=last>>17;
  current^=last<< 5;
  last=current;
  return last;
}
//should return a float between 0.0 -> 1.0
float lfsr_float(){
  union { int i; float f; } value;
  //basically, all bits are random, except the exponent bits always make 2^0
   //(this should = -1.99...->-1.0 OR 1.0->1.99...)
  value.i=(lfsr32()&0x807fffff) | 0x3f800000;
  //1.0 if original value.f = -1.0 (as i don't think 1.0 could occur otherwise)
  if(value.i==0xbf800000) return 1.0f; //1.0
  else if(value.f>=0.0f) return (value.f-1)*0.5f; //0.0 -> 0.499...
  else /*if(value.f<0.0f)*/ return 0.5f-(value.f+1)*0.5f; //5.0 -> 0.99...
}
//should do the same thing with a larger range, but uses a division
static inline float lfsr_float2(){
  return (float)((unsigned)lfsr32())/0xffffffff;
}