forked from KolibriOS/kolibrios
27 lines
583 B
C
27 lines
583 B
C
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/* Copyright (C) 1994 DJ Delorie, see COPYING.DJ for details */
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#include <math.h>
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double
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frexp(double x, int *exptr)
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{
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union {
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double d;
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unsigned char c[8];
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} u;
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u.d = x;
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/*
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* The format of the number is:
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* Sign, 12 exponent bits, 51 mantissa bits
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* The exponent is 1023 biased and there is an implicit zero.
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* We get the exponent from the upper bits and set the exponent
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* to 0x3fe (1022).
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*/
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*exptr = (int)(((u.c[7] & 0x7f) << 4) | (u.c[6] >> 4)) - 1022;
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u.c[7] &= 0x80;
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u.c[7] |= 0x3f;
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u.c[6] &= 0x0f;
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u.c[6] |= 0xe0;
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return u.d;
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}
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