49d1a4c562
also start prefering NtDll API. so far: * NtQueryInformationFile * NtClose adds a performance workaround for windows unicode conversion. but that should probably be removed before merging
39 lines
854 B
C
39 lines
854 B
C
/**
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* This file has no copyright assigned and is placed in the Public Domain.
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* This file is part of the mingw-w64 runtime package.
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* No warranty is given; refer to the file DISCLAIMER.PD within this package.
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*/
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/*
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* Written by J.T. Conklin <jtc@netbsd.org>.
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* Changes for long double by Ulrich Drepper <drepper@cygnus.com>
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* Public domain.
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*/
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#include <math.h>
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double
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logb (double x)
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{
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#ifdef __x86_64__
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__mingw_dbl_type_t hlp;
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int lx, hx;
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hlp.x = x;
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lx = hlp.lh.low;
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hx = hlp.lh.high & 0x7fffffff; /* high |x| */
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if ((hx | lx) == 0)
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return -1.0 / fabs (x);
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if (hx >= 0x7ff00000)
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return x * x;
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if ((hx >>= 20) == 0) /* IEEE 754 logb */
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return -1022.0;
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return (double) (hx - 1023);
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#else
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double res = 0.0;
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asm volatile (
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"fxtract\n\t"
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"fstp %%st" : "=t" (res) : "0" (x));
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return res;
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#endif
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}
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