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56c81132cc
The instructions xsxexpdp and xsxexpqp introduced on POWER9 extract the exponent from a double-precision and quad-precision floating-point respectively, thus they can be used to improve ilogb, ilogbf and ilogbf128.
31 lines
724 B
C
31 lines
724 B
C
#include <math.h>
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#include <errno.h>
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#include <limits.h>
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#include <math_private.h>
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#include <fenv.h>
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#if _GL_HAS_BUILTIN_ILOGB
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int
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M_DECL_FUNC (__ilogb) (FLOAT x)
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{
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int r;
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/* Check for exceptional cases. */
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if (! M_SUF(__builtin_test_dc_ilogb) (x, 0x7f))
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r = M_SUF (__builtin_ilogb) (x);
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else
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/* Fallback to the generic ilogb if x is NaN, Inf or subnormal. */
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r = M_SUF (__ieee754_ilogb) (x);
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if (__builtin_expect (r == FP_ILOGB0, 0)
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|| __builtin_expect (r == FP_ILOGBNAN, 0)
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|| __builtin_expect (r == INT_MAX, 0))
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{
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__set_errno (EDOM);
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__feraiseexcept (FE_INVALID);
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}
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return r;
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}
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declare_mgen_alias (__ilogb, ilogb)
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#else
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#include <math/w_ilogb_template.c>
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#endif
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