61 lines
1021 B
C
61 lines
1021 B
C
/*
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libc/ieee_float/frexp.c
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Created: Oct 14, 1993 by Philip Homburg <philip@cs.vu.nl>
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Implementation of frexp that directly manipulates the exponent bits in an
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ieee float
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*/
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#include <sys/types.h>
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#include <math.h>
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#include "ieee_float.h"
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double frexp(value, eptr)
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double value;
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int *eptr;
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{
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struct f64 *f64p;
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int exp, exp_bias;
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double factor;
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f64p= (struct f64 *)&value;
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exp_bias= 0;
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exp= F64_GET_EXP(f64p);
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if (exp == F64_EXP_MAX)
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{ /* Either infinity or Nan */
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*eptr= 0;
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return value;
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}
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if (exp == 0)
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{
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/* Either 0 or denormal */
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if (F64_GET_MANT_LOW(f64p) == 0 &&
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F64_GET_MANT_HIGH(f64p) == 0)
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{
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*eptr= 0;
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return value;
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}
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/* Multiply by 2^64 */
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factor= 65536.0; /* 2^16 */
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factor *= factor; /* 2^32 */
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factor *= factor; /* 2^64 */
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value *= factor;
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exp_bias= 64;
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exp= F64_GET_EXP(f64p);
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}
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exp= exp - F64_EXP_BIAS - exp_bias + 1;
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*eptr= exp;
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F64_SET_EXP(f64p, F64_EXP_BIAS-1);
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return value;
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}
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/*
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* $PchId: frexp.c,v 1.3 1996/02/22 21:01:39 philip Exp $
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*/
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