X-Git-Url: http://nsz.repo.hu/git/?p=musl;a=blobdiff_plain;f=src%2Fmath%2Fcoshl.c;h=d09070bbf7a4962d7f1f66826ef58cbaafce6158;hp=bcc9128aa163344988bf83d35eec9ad80d4ec560;hb=5652d70054daf3c2c9b6d475fdf9d24a940e51aa;hpb=b69f695acedd4ce2798ef9ea28d834ceccc789bd

diff --git a/src/math/coshl.c b/src/math/coshl.c
index bcc9128a..d09070bb 100644
--- a/src/math/coshl.c
+++ b/src/math/coshl.c
@@ -1,35 +1,3 @@
-/* origin: OpenBSD /usr/src/lib/libm/src/ld80/e_coshl.c */
-/*
- * ====================================================
- * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
- *
- * Developed at SunPro, a Sun Microsystems, Inc. business.
- * Permission to use, copy, modify, and distribute this
- * software is freely granted, provided that this notice
- * is preserved.
- * ====================================================
- */
-/* coshl(x)
- * Method :
- * mathematically coshl(x) if defined to be (exp(x)+exp(-x))/2
- *      1. Replace x by |x| (coshl(x) = coshl(-x)).
- *      2.
- *                                                      [ exp(x) - 1 ]^2
- *          0        <= x <= ln2/2  :  coshl(x) := 1 + -------------------
- *                                                         2*exp(x)
- *
- *                                                 exp(x) +  1/exp(x)
- *          ln2/2    <= x <= 22     :  coshl(x) := -------------------
- *                                                         2
- *          22       <= x <= lnovft :  coshl(x) := expl(x)/2
- *          lnovft   <= x <= ln2ovft:  coshl(x) := expl(x/2)/2 * expl(x/2)
- *          ln2ovft  <  x           :  coshl(x) := huge*huge (overflow)
- *
- * Special cases:
- *      coshl(x) is |x| if x is +INF, -INF, or NaN.
- *      only coshl(0)=1 is exact for finite x.
- */
-
 #include "libm.h"
 
 #if LDBL_MANT_DIG == 53 && LDBL_MAX_EXP == 1024
@@ -38,49 +6,39 @@ long double coshl(long double x)
 	return cosh(x);
 }
 #elif LDBL_MANT_DIG == 64 && LDBL_MAX_EXP == 16384
-static const long double one = 1.0, half = 0.5, huge = 1.0e4900L;
-
 long double coshl(long double x)
 {
-	long double t,w;
-	int32_t ex;
-	uint32_t mx,lx;
-
-	/* High word of |x|. */
-	GET_LDOUBLE_WORDS(ex, mx, lx, x);
-	ex &= 0x7fff;
-
-	/* x is INF or NaN */
-	if (ex == 0x7fff) return x*x;
-
-	/* |x| in [0,0.5*ln2], return 1+expm1l(|x|)^2/(2*expl(|x|)) */
-	if (ex < 0x3ffd || (ex == 0x3ffd && mx < 0xb17217f7u)) {
-		t = expm1l(fabsl(x));
-		w = one + t;
-		if (ex < 0x3fbc) return w;    /* cosh(tiny) = 1 */
-		return one+(t*t)/(w+w);
-	}
-
-	/* |x| in [0.5*ln2,22], return (exp(|x|)+1/exp(|x|)/2; */
-	if (ex < 0x4003 || (ex == 0x4003 && mx < 0xb0000000u)) {
-		t = expl(fabsl(x));
-		return half*t + half/t;
+	union {
+		long double f;
+		struct{uint64_t m; uint16_t se; uint16_t pad;} i;
+	} u = {.f = x};
+	unsigned ex = u.i.se & 0x7fff;
+	uint32_t w;
+	long double t;
+
+	/* |x| */
+	u.i.se = ex;
+	x = u.f;
+	w = u.i.m >> 32;
+
+	/* |x| < log(2) */
+	if (ex < 0x3fff-1 || (ex == 0x3fff-1 && w < 0xb17217f7)) {
+		if (ex < 0x3fff-32) {
+			FORCE_EVAL(x + 0x1p120f);
+			return 1;
+		}
+		t = expm1l(x);
+		return 1 + t*t/(2*(1+t));
 	}
 
-	/* |x| in [22, ln(maxdouble)] return half*exp(|x|) */
-	if (ex < 0x400c || (ex == 0x400c && mx < 0xb1700000u))
-		return half*expl(fabsl(x));
-
-	/* |x| in [log(maxdouble), log(2*maxdouble)) */
-	if (ex == 0x400c && (mx < 0xb174ddc0u ||
-	     (mx == 0xb174ddc0u && lx < 0x31aec0ebu)))
-	{
-		w = expl(half*fabsl(x));
-		t = half*w;
-		return t*w;
+	/* |x| < log(LDBL_MAX) */
+	if (ex < 0x3fff+13 || (ex == 0x3fff+13 && w < 0xb17217f7)) {
+		t = expl(x);
+		return 0.5*(t + 1/t);
 	}
 
-	/* |x| >= log(2*maxdouble), cosh(x) overflow */
-	return huge*huge;
+	/* |x| > log(LDBL_MAX) or nan */
+	t = expl(0.5*x);
+	return 0.5*t*t;
 }
 #endif