10  * See the License for the specific language governing permissions
  11  * and limitations under the License.
  12  *
  13  * When distributing Covered Code, include this CDDL HEADER in each
  14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
  15  * If applicable, add the following below this CDDL HEADER, with the
  16  * fields enclosed by brackets "[]" replaced with your own identifying
  17  * information: Portions Copyright [yyyy] [name of copyright owner]
  18  *
  19  * CDDL HEADER END
  20  */
  21 
  22 /*
  23  * Copyright 2011 Nexenta Systems, Inc.  All rights reserved.
  24  */
  25 /*
  26  * Copyright 2006 Sun Microsystems, Inc.  All rights reserved.
  27  * Use is subject to license terms.
  28  */
  29 
  30 #pragma weak cexp = __cexp
  31 
  32 /* INDENT OFF */
  33 /*
  34  * dcomplex cexp(dcomplex z);
  35  *
  36  *  x+iy    x
  37  * e     = e  (cos(y)+i*sin(y))
  38  *
  39  * Over/underflow issue
  40  * --------------------
  41  * exp(x) may be huge but cos(y) or sin(y) may be tiny. So we use
  42  * function __k_cexp(x,&n) to return exp(x) = __k_cexp(x,&n)*2**n.
  43  * Thus if exp(x+iy) = A + Bi and t = __k_cexp(x,&n), then
  44  *         A = t*cos(y)*2**n,   B = t*sin(y)*2**n
  45  *
  46  * Purge off all exceptional arguments:
  47  *      (x,0) --> (exp(x),0)         for all x, include inf and NaN
  48  *      (+inf, y) --> (+inf, NaN)    for inf, nan
  49  *      (-inf, y) --> (+-0, +-0)     for y = inf, nan
  50  *      (x,+-inf/NaN) --> (NaN,NaN)  for finite x

  10  * See the License for the specific language governing permissions
  11  * and limitations under the License.
  12  *
  13  * When distributing Covered Code, include this CDDL HEADER in each
  14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
  15  * If applicable, add the following below this CDDL HEADER, with the
  16  * fields enclosed by brackets "[]" replaced with your own identifying
  17  * information: Portions Copyright [yyyy] [name of copyright owner]
  18  *
  19  * CDDL HEADER END
  20  */
  21 
  22 /*
  23  * Copyright 2011 Nexenta Systems, Inc.  All rights reserved.
  24  */
  25 /*
  26  * Copyright 2006 Sun Microsystems, Inc.  All rights reserved.
  27  * Use is subject to license terms.
  28  */
  29 
  30 #pragma weak __cexp = cexp
  31 
  32 /* INDENT OFF */
  33 /*
  34  * dcomplex cexp(dcomplex z);
  35  *
  36  *  x+iy    x
  37  * e     = e  (cos(y)+i*sin(y))
  38  *
  39  * Over/underflow issue
  40  * --------------------
  41  * exp(x) may be huge but cos(y) or sin(y) may be tiny. So we use
  42  * function __k_cexp(x,&n) to return exp(x) = __k_cexp(x,&n)*2**n.
  43  * Thus if exp(x+iy) = A + Bi and t = __k_cexp(x,&n), then
  44  *         A = t*cos(y)*2**n,   B = t*sin(y)*2**n
  45  *
  46  * Purge off all exceptional arguments:
  47  *      (x,0) --> (exp(x),0)         for all x, include inf and NaN
  48  *      (+inf, y) --> (+inf, NaN)    for inf, nan
  49  *      (-inf, y) --> (+-0, +-0)     for y = inf, nan
  50  *      (x,+-inf/NaN) --> (NaN,NaN)  for finite x