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2017-04-21fix scalbn when result is in the subnormal rangeSzabolcs Nagy1-4/+6
in nearest rounding mode scalbn could introduce double rounding error when an intermediate value and the final result were both in the subnormal range e.g. scalbn(0x1.7ffffffffffffp-1, -1073) returned 0x1p-1073 instead of 0x1p-1074, because the intermediate computation got rounded to 0x1.8p-1023. with the fix an intermediate value can only be in the subnormal range if the final result is 0 which is correct even after double rounding. (there still can be two roundings so signals may be raised twice, but that's only observable with trapping exceptions which is not supported.)
2013-09-05math: use float_t and double_t in scalbnf and scalbnSzabolcs Nagy1-8/+10
remove STRICT_ASSIGN (c99 semantics is assumed) and use the conventional union to prepare the scaling factor (so libm.h is no longer needed)
2013-08-15math: minor scalbn*.c simplificationSzabolcs Nagy1-8/+4
2012-11-13math: excess precision fix modf, modff, scalbn, scalbnfSzabolcs Nagy1-8/+6
old code was correct only if the result was stored (without the excess precision) or musl was compiled with -ffloat-store. now we use STRICT_ASSIGN to work around the issue. (see note 160 in c11 section 6.8.6.4)
2012-11-13math: fix scalbn and scalbnf on overflow/underflowSzabolcs Nagy1-5/+12
old code was correct only if the result was stored (without the excess precision) or musl was compiled with -ffloat-store. (see note 160 in n1570.pdf section 6.8.6.4)
2012-03-19simplify scalbn*.c implementationsnsz1-55/+21
The old scalbn.c was wrong and slow, the new one is just slow. (scalbn(0x1p+1023,-2097) should give 0x1p-1074, but the old code gave 0)
2012-03-13first commit of the new libm!Rich Felker1-0/+62
thanks to the hard work of Szabolcs Nagy (nsz), identifying the best (from correctness and license standpoint) implementations from freebsd and openbsd and cleaning them up! musl should now fully support c99 float and long double math functions, and has near-complete complex math support. tgmath should also work (fully on gcc-compatible compilers, and mostly on any c99 compiler). based largely on commit 0376d44a890fea261506f1fc63833e7a686dca19 from nsz's libm git repo, with some additions (dummy versions of a few missing long double complex functions, etc.) by me. various cleanups still need to be made, including re-adding (if they're correct) some asm functions that were dropped.