30 lines
559 B
C
30 lines
559 B
C
#include "libc/math/libm.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 round(double x) {
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union {
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double f;
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uint64_t i;
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} u = {x};
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int e = u.i >> 52 & 0x7ff;
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double_t y;
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if (e >= 0x3ff + 52) return x;
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if (u.i >> 63) x = -x;
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y = x + toint - toint - x;
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if (y > 0.5) {
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y = y + x - 1;
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} else if (y <= -0.5) {
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y = y + x + 1;
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} else {
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y = y + x;
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}
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if (u.i >> 63) y = -y;
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return y;
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}
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