You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
111 lines
3.6 KiB
111 lines
3.6 KiB
// cl_LF_to_double().
|
|
|
|
// General includes.
|
|
#include "cl_sysdep.h"
|
|
|
|
// Specification.
|
|
#include "cln/lfloat.h"
|
|
|
|
|
|
// Implementation.
|
|
|
|
#include "cl_LF.h"
|
|
#include "cl_LF_impl.h"
|
|
#include "cl_DF.h"
|
|
#include "cl_DS.h"
|
|
|
|
namespace cln {
|
|
|
|
double double_approx (const cl_LF& x)
|
|
{
|
|
// x entpacken:
|
|
var cl_signean sign;
|
|
var sintL exp;
|
|
var uintD* ptr;
|
|
var uintC len;
|
|
LF_decode(x, { return 0.0; }, sign=,exp=,ptr=,len=,);
|
|
// intDsize*len-DF_mant_len-1 Bits der Mantisse wegrunden:
|
|
// erste k := ceiling(DF_mant_len+2,intDsize) Digits nach manthi,mantlo holen:
|
|
var const int shiftcount = ceiling(DF_mant_len+2,intDsize)*intDsize-(DF_mant_len+1);
|
|
union { dfloat eksplicit; double machine_double; } u;
|
|
#if (cl_word_size==64)
|
|
var uint64 mant = get_max64_Dptr(DF_mant_len+2,ptr);
|
|
ptr = ptr mspop ceiling(DF_mant_len+2,intDsize);
|
|
if ( ((mant & bit(shiftcount-1)) ==0) // Bit 10 war 0 -> abrunden
|
|
|| ( ((mant & (bit(shiftcount-1)-1)) ==0) // war 1, Bits 9..0 >0 -> aufrunden
|
|
&& !test_loop_msp(ptr,len-ceiling(DF_mant_len+2,intDsize)) // weitere Bits /=0 -> aufrunden
|
|
// round-to-even
|
|
&& ((mant & bit(shiftcount)) ==0)
|
|
) )
|
|
// abrunden
|
|
{ mant = mant >> shiftcount; }
|
|
else
|
|
// aufrunden
|
|
{ mant = mant >> shiftcount;
|
|
mant = mant+1;
|
|
if (mant >= bit(DF_mant_len+1))
|
|
// Überlauf durchs Runden
|
|
{ mant = mant>>1; exp = exp+1; } // Mantisse rechts schieben
|
|
}
|
|
if (exp > (sintL)(DF_exp_high-DF_exp_mid))
|
|
{ u.eksplicit =
|
|
((sint64)sign & bit(63))
|
|
| ((uint64)(bit(DF_exp_len)-1) << DF_mant_len); // Infinity
|
|
}
|
|
else
|
|
if (exp < (sintL)(DF_exp_low-DF_exp_mid))
|
|
{ u.eksplicit = ((sint64)sign & bit(63)); } // 0.0
|
|
else
|
|
{ u.eksplicit =
|
|
((sint64)sign & bit(63)) /* Vorzeichen */
|
|
| ((uint64)(exp+DF_exp_mid) << DF_mant_len) /* Exponent */
|
|
| ((uint64)mant & (bit(DF_mant_len)-1)); /* Mantisse */
|
|
}
|
|
#else
|
|
var uint32 manthi = get_max32_Dptr(DF_mant_len+2-32,ptr);
|
|
var uint32 mantlo = get_32_Dptr(ptr mspop ceiling(DF_mant_len+2-32,intDsize));
|
|
ptr = ptr mspop ceiling(DF_mant_len+2,intDsize);
|
|
if ( ((mantlo & bit(shiftcount-1)) ==0) // Bit 10 war 0 -> abrunden
|
|
|| ( ((mantlo & (bit(shiftcount-1)-1)) ==0) // war 1, Bits 9..0 >0 -> aufrunden
|
|
&& !test_loop_msp(ptr,len-ceiling(DF_mant_len+2,intDsize)) // weitere Bits /=0 -> aufrunden
|
|
// round-to-even
|
|
&& ((mantlo & bit(shiftcount)) ==0)
|
|
) )
|
|
// abrunden
|
|
{ mantlo = (manthi << (32-shiftcount)) | (mantlo >> shiftcount);
|
|
manthi = manthi >> shiftcount;
|
|
}
|
|
else
|
|
// aufrunden
|
|
{ mantlo = (manthi << (32-shiftcount)) | (mantlo >> shiftcount);
|
|
manthi = manthi >> shiftcount;
|
|
mantlo = mantlo+1;
|
|
if (mantlo==0)
|
|
{ manthi = manthi+1;
|
|
if (manthi >= bit(DF_mant_len+1-32))
|
|
// Überlauf durchs Runden
|
|
{ manthi = manthi>>1; exp = exp+1; } // Mantisse rechts schieben
|
|
} }
|
|
if (exp > (sintL)(DF_exp_high-DF_exp_mid))
|
|
{ u.eksplicit.semhi =
|
|
((sint32)sign & bit(31))
|
|
| ((uint32)(bit(DF_exp_len)-1) << (DF_mant_len-32)); // Infinity
|
|
u.eksplicit.mlo = 0;
|
|
}
|
|
else
|
|
if (exp < (sintL)(DF_exp_low-DF_exp_mid))
|
|
{ u.eksplicit.semhi = ((sint32)sign & bit(31)); // 0.0
|
|
u.eksplicit.mlo = 0;
|
|
}
|
|
else
|
|
{ u.eksplicit.semhi =
|
|
((sint32)sign & bit(31)) /* Vorzeichen */
|
|
| ((uint32)(exp+DF_exp_mid) << (DF_mant_len-32)) /* Exponent */
|
|
| ((uint32)manthi & (bit(DF_mant_len-32)-1)); /* Mantisse */
|
|
u.eksplicit.mlo = mantlo;
|
|
}
|
|
#endif
|
|
return u.machine_double;
|
|
}
|
|
|
|
} // namespace cln
|