kaguya
35 lines
536 B
C
35 lines
536 B
C
#include "libm.h"
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double modf(double x, double *iptr)
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{
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union {double f; uint64_t i;} u = {x};
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uint64_t mask;
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int e = (int)(u.i>>52 & 0x7ff) - 0x3ff;
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/* no fractional part */
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if (e >= 52) {
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*iptr = x;
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if (e == 0x400 && u.i<<12 != 0) /* nan */
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return x;
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u.i &= 1ULL<<63;
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return u.f;
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}
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/* no integral part*/
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if (e < 0) {
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u.i &= 1ULL<<63;
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*iptr = u.f;
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return x;
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}
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mask = -1ULL>>12>>e;
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if ((u.i & mask) == 0) {
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*iptr = x;
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u.i &= 1ULL<<63;
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return u.f;
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}
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u.i &= ~mask;
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*iptr = u.f;
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return x - u.f;
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}
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