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-rw-r--r--src/math/coshl.c55
1 files changed, 27 insertions, 28 deletions
diff --git a/src/math/coshl.c b/src/math/coshl.c
index 36b52c02..3ea56e00 100644
--- a/src/math/coshl.c
+++ b/src/math/coshl.c
@@ -23,7 +23,7 @@
* 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)
+ * ln2ovft < x : coshl(x) := inf (overflow)
*
* Special cases:
* coshl(x) is |x| if x is +INF, -INF, or NaN.
@@ -38,49 +38,48 @@ long double coshl(long double x)
return cosh(x);
}
#elif LDBL_MANT_DIG == 64 && LDBL_MAX_EXP == 16384
-static const long double huge = 1.0e4900L;
-
long double coshl(long double x)
{
- long double t,w;
- int32_t ex;
+ union {
+ long double f;
+ struct{uint64_t m; uint16_t se; uint16_t pad;} i;
+ } u = {.f = x};
+ unsigned ex = u.i.se & 0x7fff;
+ long double t;
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| */
+ u.i.se = ex;
+ x = u.f;
+ mx = u.i.m >> 32;
+ lx = u.i.m;
/* |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 = 1.0 + t;
- if (ex < 0x3fbc) return w; /* cosh(tiny) = 1 */
- return 1.0+(t*t)/(w+w);
+ if (ex < 0x3fff-2 || (ex == 0x3fff-2 && mx < 0xb17217f7)) {
+ t = expm1l(x);
+ if (ex < 0x3fff-64)
+ return 1;
+ return 1 + t*t/(2*(1+t));
}
/* |x| in [0.5*ln2,22], return (exp(|x|)+1/exp(|x|)/2; */
- if (ex < 0x4003 || (ex == 0x4003 && mx < 0xb0000000u)) {
- t = expl(fabsl(x));
+ if (ex < 0x3fff+4 || (ex == 0x3fff+4 && mx < 0xb0000000)) {
+ t = expl(x);
return 0.5*t + 0.5/t;
}
/* |x| in [22, ln(maxdouble)] return 0.5*exp(|x|) */
- if (ex < 0x400c || (ex == 0x400c && mx < 0xb1700000u))
- return 0.5*expl(fabsl(x));
+ if (ex < 0x3fff+13 || (ex == 0x3fff+13 && mx < 0xb1700000))
+ return 0.5*expl(x);
/* |x| in [log(maxdouble), log(2*maxdouble)) */
- if (ex == 0x400c && (mx < 0xb174ddc0u ||
- (mx == 0xb174ddc0u && lx < 0x31aec0ebu)))
- {
- w = expl(0.5*fabsl(x));
- t = 0.5*w;
- return t*w;
+ if (ex == 0x3fff+13 && (mx < 0xb174ddc0 ||
+ (mx == 0xb174ddc0 && lx < 0x31aec0eb))) {
+ t = expl(0.5*x);
+ return 0.5*t*t;
}
- /* |x| >= log(2*maxdouble), cosh(x) overflow */
- return huge*huge;
+ /* |x| >= log(2*maxdouble) or nan */
+ return x*0x1p16383L;
}
#endif