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https://git.code.sf.net/p/mingw-w64/mingw-w64
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43 lines
1.2 KiB
C
43 lines
1.2 KiB
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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#include <math.h>
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#include <fenv.h>
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long long llrint (double x)
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{
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long long retval = 0ll;
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#if defined(_AMD64_) || defined(__x86_64__) || defined(_X86_) || defined(__i386__)
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__asm__ __volatile__ ("fistpll %0" : "=m" (retval) : "t" (x) : "st");
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#else
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int mode = fegetround();
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if (mode == FE_DOWNWARD)
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retval = (long long)floor(x);
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else if (mode == FE_UPWARD)
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retval = (long long)ceil(x);
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else if (mode == FE_TOWARDZERO)
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retval = x >= 0 ? (long long)floor(x) : (long long)ceil(x);
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else {
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// Break `x` into integral and fractional parts.
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double intg, frac;
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frac = modf(x, &intg);
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frac = fabs(frac);
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// Convert the truncated integral part to an integer.
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retval = intg;
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if (frac < 0.5) {
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// Round towards zero.
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} else if (frac > 0.5) {
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// Round towards infinities.
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retval += signbit(x) ? -1 : 1;
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} else {
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// Round to the nearest even number.
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retval += retval % 2;
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}
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}
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#endif
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return retval;
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}
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