Fix some exceptional cases where the sign of the result is unspecified

but must still satisfy ccosh(conj(z)) == conj(ccosh(z)) and ccosh(-z) ==
ccosh(z).

In collaboration with:	bde
This commit is contained in:
Tijl Coosemans 2015-06-15 20:11:06 +00:00
parent 19e58304b3
commit db7548d040
2 changed files with 32 additions and 34 deletions

View File

@ -32,6 +32,8 @@
*
* Exceptional values are noted in the comments within the source code.
* These values and the return value were taken from n1124.pdf.
* The sign of the result for some exceptional values is unspecified but
* must satisfy both cosh(conj(z)) == conj(cosh(z)) and cosh(-z) == cosh(z).
*/
#include <sys/cdefs.h>
@ -63,7 +65,7 @@ ccosh(double complex z)
if (ix < 0x7ff00000 && iy < 0x7ff00000) {
if ((iy | ly) == 0)
return (CMPLX(cosh(x), x * y));
if (ix < 0x40360000) /* small x: normal case */
if (ix < 0x40360000) /* |x| < 22: normal case */
return (CMPLX(cosh(x) * cos(y), sinh(x) * sin(y)));
/* |x| >= 22, so cosh(x) ~= exp(|x|) */
@ -83,28 +85,27 @@ ccosh(double complex z)
}
/*
* cosh(+-0 +- I Inf) = dNaN + I sign(d(+-0, dNaN))0.
* The sign of 0 in the result is unspecified. Choice = normally
* the same as dNaN. Raise the invalid floating-point exception.
* cosh(+-0 +- I Inf) = dNaN + I (+-)(+-)0.
* The sign of 0 in the result is unspecified. Choice = product
* of the signs of the argument. Raise the invalid floating-point
* exception.
*
* cosh(+-0 +- I NaN) = d(NaN) + I sign(d(+-0, NaN))0.
* The sign of 0 in the result is unspecified. Choice = normally
* the same as d(NaN).
* cosh(+-0 +- I NaN) = d(NaN) + I (+-)(+-)0.
* The sign of 0 in the result is unspecified. Choice = product
* of the signs of the argument.
*/
if ((ix | lx) == 0 && iy >= 0x7ff00000)
return (CMPLX(y - y, copysign(0, x * (y - y))));
if ((ix | lx) == 0) /* && iy >= 0x7ff00000 */
return (CMPLX(y - y, x * copysign(0, y)));
/*
* cosh(+-Inf +- I 0) = +Inf + I (+-)(+-)0.
*
* cosh(NaN +- I 0) = d(NaN) + I sign(d(NaN, +-0))0.
* The sign of 0 in the result is unspecified.
* cosh(NaN +- I 0) = d(NaN) + I (+-)(+-)0.
* The sign of 0 in the result is unspecified. Choice = product
* of the signs of the argument.
*/
if ((iy | ly) == 0 && ix >= 0x7ff00000) {
if (((hx & 0xfffff) | lx) == 0)
if ((iy | ly) == 0) /* && ix >= 0x7ff00000 */
return (CMPLX(x * x, copysign(0, x) * y));
return (CMPLX(x * x, copysign(0, (x + x) * y)));
}
/*
* cosh(x +- I Inf) = dNaN + I dNaN.
@ -114,7 +115,7 @@ ccosh(double complex z)
* Optionally raises the invalid floating-point exception for finite
* nonzero x. Choice = don't raise (except for signaling NaNs).
*/
if (ix < 0x7ff00000 && iy >= 0x7ff00000)
if (ix < 0x7ff00000) /* && iy >= 0x7ff00000 */
return (CMPLX(y - y, x * (y - y)));
/*
@ -126,10 +127,10 @@ ccosh(double complex z)
*
* cosh(+-Inf + I y) = +Inf cos(y) +- I Inf sin(y)
*/
if (ix >= 0x7ff00000 && ((hx & 0xfffff) | lx) == 0) {
if (ix == 0x7ff00000 && lx == 0) {
if (iy >= 0x7ff00000)
return (CMPLX(x * x, x * (y - y)));
return (CMPLX((x * x) * cos(y), x * sin(y)));
return (CMPLX(INFINITY, x * (y - y)));
return (CMPLX(INFINITY * cos(y), x * sin(y)));
}
/*

View File

@ -25,7 +25,7 @@
*/
/*
* Hyperbolic cosine of a complex argument. See s_ccosh.c for details.
* Float version of ccosh(). See s_ccosh.c for details.
*/
#include <sys/cdefs.h>
@ -56,13 +56,13 @@ ccoshf(float complex z)
if (ix < 0x7f800000 && iy < 0x7f800000) {
if (iy == 0)
return (CMPLXF(coshf(x), x * y));
if (ix < 0x41100000) /* small x: normal case */
if (ix < 0x41100000) /* |x| < 9: normal case */
return (CMPLXF(coshf(x) * cosf(y), sinhf(x) * sinf(y)));
/* |x| >= 9, so cosh(x) ~= exp(|x|) */
if (ix < 0x42b17218) {
/* x < 88.7: expf(|x|) won't overflow */
h = expf(fabsf(x)) * 0.5f;
h = expf(fabsf(x)) * 0.5F;
return (CMPLXF(h * cosf(y), copysignf(h, x) * sinf(y)));
} else if (ix < 0x4340b1e7) {
/* x < 192.7: scale to avoid overflow */
@ -75,22 +75,19 @@ ccoshf(float complex z)
}
}
if (ix == 0 && iy >= 0x7f800000)
return (CMPLXF(y - y, copysignf(0, x * (y - y))));
if (ix == 0) /* && iy >= 0x7f800000 */
return (CMPLXF(y - y, x * copysignf(0, y)));
if (iy == 0 && ix >= 0x7f800000) {
if ((hx & 0x7fffff) == 0)
if (iy == 0) /* && ix >= 0x7f800000 */
return (CMPLXF(x * x, copysignf(0, x) * y));
return (CMPLXF(x * x, copysignf(0, (x + x) * y)));
}
if (ix < 0x7f800000 && iy >= 0x7f800000)
if (ix < 0x7f800000) /* && iy >= 0x7f800000 */
return (CMPLXF(y - y, x * (y - y)));
if (ix >= 0x7f800000 && (hx & 0x7fffff) == 0) {
if (ix == 0x7f800000) {
if (iy >= 0x7f800000)
return (CMPLXF(x * x, x * (y - y)));
return (CMPLXF((x * x) * cosf(y), x * sinf(y)));
return (CMPLXF(INFINITY, x * (y - y)));
return (CMPLXF(INFINITY * cosf(y), x * sinf(y)));
}
return (CMPLXF((x * x) * (y - y), (x + x) * (y - y)));