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Merge remote-tracking branch 'nsz/math'
[musl]
/
src
/
math
/
cosh.c
diff --git
a/src/math/cosh.c
b/src/math/cosh.c
index
a1f7dbc
..
2fcdea8
100644
(file)
--- a/
src/math/cosh.c
+++ b/
src/math/cosh.c
@@
-23,7
+23,7
@@
* 2
* 22 <= x <= lnovft : cosh(x) := exp(x)/2
* lnovft <= x <= ln2ovft: cosh(x) := exp(x/2)/2 * exp(x/2)
* 2
* 22 <= x <= lnovft : cosh(x) := exp(x)/2
* lnovft <= x <= ln2ovft: cosh(x) := exp(x/2)/2 * exp(x/2)
- * ln2ovft < x : cosh(x) :=
huge*huge
(overflow)
+ * ln2ovft < x : cosh(x) :=
inf
(overflow)
*
* Special cases:
* cosh(x) is |x| if x is +INF, -INF, or NaN.
*
* Special cases:
* cosh(x) is |x| if x is +INF, -INF, or NaN.
@@
-32,43
+32,40
@@
#include "libm.h"
#include "libm.h"
-static const double huge = 1.0e300;
-
double cosh(double x)
{
double cosh(double x)
{
- double t, w;
- int32_t ix;
-
- GET_HIGH_WORD(ix, x);
- ix &= 0x7fffffff;
+ union {double f; uint64_t i;} u = {.f = x};
+ uint32_t ix;
+ double t;
- /* x is INF or NaN */
- if (ix >= 0x7ff00000)
- return x*x;
+ /* |x| */
+ u.i &= (uint64_t)-1/2;
+ x = u.f;
+ ix = u.i >> 32;
/* |x| in [0,0.5*ln2], return 1+expm1(|x|)^2/(2*exp(|x|)) */
if (ix < 0x3fd62e43) {
/* |x| in [0,0.5*ln2], return 1+expm1(|x|)^2/(2*exp(|x|)) */
if (ix < 0x3fd62e43) {
- t = expm1(fabs(x));
- w = 1.0+t;
+ t = expm1(x);
if (ix < 0x3c800000)
if (ix < 0x3c800000)
- return
w; /* cosh(tiny) = 1 */
- return 1
.0 + (t*t)/(w+w
);
+ return
1;
+ return 1
+ t*t/(2*(1+t)
);
}
/* |x| in [0.5*ln2,22], return (exp(|x|)+1/exp(|x|))/2; */
if (ix < 0x40360000) {
}
/* |x| in [0.5*ln2,22], return (exp(|x|)+1/exp(|x|))/2; */
if (ix < 0x40360000) {
- t = exp(
fabs(x)
);
+ t = exp(
x
);
return 0.5*t + 0.5/t;
}
/* |x| in [22, log(maxdouble)] return 0.5*exp(|x|) */
return 0.5*t + 0.5/t;
}
/* |x| in [22, log(maxdouble)] return 0.5*exp(|x|) */
- if (ix < 0x40862
E
42)
- return 0.5*exp(
fabs(x)
);
+ if (ix < 0x40862
e
42)
+ return 0.5*exp(
x
);
/* |x| in [log(maxdouble), overflowthresold] */
/* |x| in [log(maxdouble), overflowthresold] */
- if (ix <= 0x408633
CE
)
- return __expo2(
fabs(x)
);
+ if (ix <= 0x408633
ce
)
+ return __expo2(
x
);
- /* |x| > overflowthresold, cosh(x) overflow */
- return huge*huge;
+ /* overflow (or nan) */
+ x *= 0x1p1023;
+ return x;
}
}