common/complex/cexpf.c

/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License (the "License").
 * You may not use this file except in compliance with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */
/*
 * Copyright 2011 Nexenta Systems, Inc.  All rights reserved.
 */
/*
 * Copyright 2005 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */

#pragma weak __cexpf = cexpf

#include "libm.h"
#include "complex_wrapper.h"

#if defined(__i386) && !defined(__amd64)
extern int __swapRP(int);
#endif

static const float zero = 0.0F;

fcomplex
cexpf(fcomplex z) {
    fcomplex    ans;
    float       x, y, c, s;
    double      t;
    int     n, ix, iy, hx, hy;

    x = F_RE(z);
    y = F_IM(z);
    hx = THE_WORD(x);
    hy = THE_WORD(y);
    ix = hx & 0x7fffffff;
    iy = hy & 0x7fffffff;
    if (iy == 0) {      /* y = 0 */
        F_RE(ans) = expf(x);
        F_IM(ans) = y;
    } else if (ix == 0x7f800000) {  /* x is +-inf */
        if (hx < 0) {
            if (iy >= 0x7f800000) {
                F_RE(ans) = zero;
                F_IM(ans) = zero;
            } else {
                sincosf(y, &s, &c);
                F_RE(ans) = zero * c;
                F_IM(ans) = zero * s;
            }
        } else {
            if (iy >= 0x7f800000) {
                F_RE(ans) = x;
                F_IM(ans) = y - y;
            } else {
                sincosf(y, &s, &c);
                F_RE(ans) = x * c;
                F_IM(ans) = x * s;
            }
        }
    } else {
        sincosf(y, &s, &c);
        if (ix >= 0x42B171AA) { /* |x| > 88.722... ~ log(2**128) */
#if defined(__i386) && !defined(__amd64)
            int rp = __swapRP(fp_extended);
#endif
            t = __k_cexp(x, &n);
            F_RE(ans) = (float)scalbn(t * (double)c, n);
            F_IM(ans) = (float)scalbn(t * (double)s, n);
#if defined(__i386) && !defined(__amd64)
            if (rp != fp_extended)
                (void) __swapRP(rp);
#endif
        } else {
            t = expf(x);
            F_RE(ans) = t * c;
            F_IM(ans) = t * s;
        }
    }
    return (ans);
}