Szabolcs Nagy
98be442ee8
use -1/(x*x) instead of -1/(x+0) to return -inf, -0+0 is -0 in downward rounding mode
17 lines
256 B
C
17 lines
256 B
C
#include <math.h>
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#if LDBL_MANT_DIG == 53 && LDBL_MAX_EXP == 1024
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long double logbl(long double x)
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{
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return logb(x);
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}
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#else
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long double logbl(long double x)
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{
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if (!isfinite(x))
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return x * x;
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if (x == 0)
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return -1/(x*x);
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return ilogbl(x);
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}
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#endif
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