29 lines
489 B
C
29 lines
489 B
C
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#include <float.h>
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#include <math.h>
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#include <stdint.h>
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#if FLT_EVAL_METHOD==0 || FLT_EVAL_METHOD==1
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#define EPS DBL_EPSILON
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#elif FLT_EVAL_METHOD==2
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#define EPS LDBL_EPSILON
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#endif
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static const double_t toint = 1/EPS;
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double rint(double x)
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{
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union {double f; uint64_t i;} u = {x};
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int e = u.i>>52 & 0x7ff;
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int s = u.i>>63;
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double_t y;
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if (e >= 0x3ff+52)
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return x;
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if (s)
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y = x - toint + toint;
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else
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y = x + toint - toint;
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if (y == 0)
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return s ? -0.0 : 0;
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return y;
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}
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