X-Git-Url: http://nsz.repo.hu/git/?a=blobdiff_plain;ds=sidebyside;f=src%2Fmath%2Fatanhl.c;h=87cd1cdb5f325f01cf12d19594efbcead93472b1;hb=0a7b4323b0f2b944dbd47a813c0c6e6813e7fd67;hp=b4c5e58b97f2d5070073f3b418ba74edd9a89c18;hpb=969ddbc423238291d5c7982790bbe72720627ba4;p=musl

diff --git a/src/math/atanhl.c b/src/math/atanhl.c
index b4c5e58b..87cd1cdb 100644
--- a/src/math/atanhl.c
+++ b/src/math/atanhl.c
@@ -5,14 +5,11 @@ long double atanhl(long double x)
 {
 	return atanh(x);
 }
-#elif LDBL_MANT_DIG == 64 && LDBL_MAX_EXP == 16384
+#elif (LDBL_MANT_DIG == 64 || LDBL_MANT_DIG == 113) && LDBL_MAX_EXP == 16384
 /* atanh(x) = log((1+x)/(1-x))/2 = log1p(2x/(1-x))/2 ~= x + x^3/3 + o(x^5) */
 long double atanhl(long double x)
 {
-	union {
-		long double f;
-		struct{uint64_t m; uint16_t se; uint16_t pad;} i;
-	} u = {.f = x};
+	union ldshape u = {x};
 	unsigned e = u.i.se & 0x7fff;
 	unsigned s = u.i.se >> 15;
 
@@ -20,11 +17,18 @@ long double atanhl(long double x)
 	u.i.se = e;
 	x = u.f;
 
-	if (e < 0x3fff - 1) {
-		/* |x| < 0.5, up to 1.7ulp error */
-		x = 0.5*log1pl(2*x + 2*x*x/(1-x));
+	if (e < 0x3ff - 1) {
+		if (e < 0x3ff - LDBL_MANT_DIG/2) {
+			/* handle underflow */
+			if (e == 0)
+				FORCE_EVAL((float)x);
+		} else {
+			/* |x| < 0.5, up to 1.7ulp error */
+			x = 0.5*log1pl(2*x + 2*x*x/(1-x));
+		}
 	} else {
-		x = 0.5*log1pl(2*x/(1-x));
+		/* avoid overflow */
+		x = 0.5*log1pl(2*(x/(1-x)));
 	}
 	return s ? -x : x;
 }