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53 lines
1.7 KiB
53 lines
1.7 KiB
// cl_DF_to_double().
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// General includes.
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#include "cl_sysdep.h"
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// Specification.
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#include "cl_dfloat.h"
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// Implementation.
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#include "cl_DF.h"
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double cl_double_approx (const cl_DF& obj)
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{
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union { dfloat eksplicit; double machine_double; } u;
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#define val u.eksplicit
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val = TheDfloat(obj)->dfloat_value;
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// Der Exponent muß um DF_exp_mid-1022 erniedrigt werden.
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if (DF_exp_mid>1022)
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#if (cl_word_size==64)
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{ var uintL exp = (val >> DF_mant_len) & (bit(DF_exp_len)-1); // e
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if (exp < DF_exp_mid-1022+1)
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{ // produziere denormalisiertes Float
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val = (val & minus_bit(DF_exp_len+DF_mant_len)) // selbes Vorzeichen
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| ((sint64)0 << DF_mant_len) // Exponent 0
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| (((val & (bit(DF_mant_len)-1)) | bit(DF_mant_len)) // Mantisse shiften
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>> (DF_exp_mid-1022+1 - exp) // shiften
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);
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}
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else
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{ val -= (sint64)(DF_exp_mid - 1022) << DF_mant_len; }
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}
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#else
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{ var uintL exp = (val.semhi >> (DF_mant_len-32)) & (bit(DF_exp_len)-1); // e
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if (exp < DF_exp_mid-1022+1)
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{ // produziere denormalisiertes Float
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var uintL shiftcount = DF_exp_mid-1022+1 - exp;
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val.mlo = val.mlo >> shiftcount; // Mantisse shiften
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val.mlo |= val.semhi << (32-shiftcount);
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val.semhi = (val.semhi & minus_bit(DF_exp_len+DF_mant_len-32)) // selbes Vorzeichen
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| ((sint32)0 << (DF_mant_len-32)) // Exponent 0
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| (((val.semhi & (bit(DF_mant_len-32)-1)) | bit(DF_mant_len-32)) // Mantisse shiften
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>> shiftcount // shiften
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);
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}
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else
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{ val.semhi -= (sint32)(DF_exp_mid - 1022) << (DF_mant_len-32); }
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}
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#endif
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#undef val
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return u.machine_double;
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}
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