
Date: Tue, 23 Aug 2016 21:47:53 +0200 From: Szabolcs Nagy <nsz@...t70.net> To: musl@...ts.openwall.com Cc: Roland McGrath <mcgrathr@...gle.com> Subject: [PATCH] math: fix 128bit long double inverse trigonometric functions there was a copy paste error that could cause large ulp errors in atan2l, atanl, asinl and acosl on aarch64, mips64 and mipsn32. (the implementation is from freebsd fdlibm, but the tail end of the polynomial was wrong. 128 bit long double functions are not yet tested so this went undetected.)  this was found by the change https://fuchsia.googlesource.com/magenta/+/5fd5aa1b2e567f6b6633fc84ea84443b496f7eb6%5E%21 i tested manually at a few inputs that the patch is sound, the bug did not cause completely wrong results, the first couple bits were fine since the leading coefficients were correct. src/math/__invtrigl.c  2 + 1 file changed, 1 insertion(+), 1 deletion() diff git a/src/math/__invtrigl.c b/src/math/__invtrigl.c index ef7f4e1..48f83aa 100644  a/src/math/__invtrigl.c +++ b/src/math/__invtrigl.c @@ 57,7 +57,7 @@ long double __invtrigl_R(long double z) { long double p, q; p = z*(pS0+z*(pS1+z*(pS2+z*(pS3+z*(pS4+z*(pS5+z*(pS6+z*(pS7+z*(pS8+z*pS9)))))))));  q = 1.0+z*(qS1+z*(qS2+z*(qS3+z*(qS4+z*(qS5+z*(pS6+z*(pS7+z*(pS8+z*pS9)))))))); + q = 1.0+z*(qS1+z*(qS2+z*(qS3+z*(qS4+z*(qS5+z*(qS6+z*(qS7+z*(qS8+z*qS9)))))))); return p/q; } #endif  2.8.1
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