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C23 adds various <math.h> function families originally defined in TS 18661-4. Add the compoundn functions, which compute (1+X) to the power Y for integer Y (and X at least -1). The integer exponent has type long long int in C23; it was intmax_t in TS 18661-4, and as with other interfaces changed after their initial appearance in the TS, I don't think we need to support the original version of the interface. Note that these functions are "compoundn" with a trailing "n", *not* "compound" (CORE-MATH has the wrong name, for example). As with pown, I strongly encourage searching for worst cases for ulps error for these implementations (necessarily non-exhaustively, given the size of the input space). I also expect a custom implementation for a given format could be much faster as well as more accurate (I haven't tested or benchmarked the CORE-MATH implementation for binary32); this is one of the more complicated and less efficient functions to implement in a type-generic way. As with exp2m1 and exp10m1, this showed up places where the powerpc64le IFUNC setup is not as self-contained as one might hope (in this case, without the changes specific to powerpc64le, there were undefined references to __GI___expf128). Tested for x86_64 and x86, and with build-many-glibcs.py.
9 lines
121 B
C
9 lines
121 B
C
#include "nldbl-compat.h"
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double
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attribute_hidden
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compoundnl (double x, long long int y)
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{
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return compoundn (x, y);
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}
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