usr/src/lib/libc/sparc/fp/_Q_dtoq.c

   1 /*
   2  * CDDL HEADER START
   3  *
   4  * The contents of this file are subject to the terms of the
   5  * Common Development and Distribution License, Version 1.0 only
   6  * (the "License").  You may not use this file except in compliance
   7  * with the License.
   8  *
   9  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
  10  * or http://www.opensolaris.org/os/licensing.
  11  * See the License for the specific language governing permissions
  12  * and limitations under the License.
  13  *
  14  * When distributing Covered Code, include this CDDL HEADER in each
  15  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
  16  * If applicable, add the following below this CDDL HEADER, with the
  17  * fields enclosed by brackets "[]" replaced with your own identifying
  18  * information: Portions Copyright [yyyy] [name of copyright owner]
  19  *
  20  * CDDL HEADER END
  21  */
  22 /*
  23  * Copyright (c) 1994-1997, by Sun Microsystems, Inc.
  24  * All rights reserved.
  25  */
  26
  27 #pragma ident   "%Z%%M% %I%     %E% SMI"
  28
  29 #include "quad.h"
  30
  31 #ifdef __sparcv9
  32
  33 /*
  34  * _Qp_dtoq(pz, x) sets *pz = (long double)x.
  35  */
  36 void
  37 _Qp_dtoq(union longdouble *pz, double x)
  38
  39 #else
  40
  41 /*
  42  * _Q_dtoq(x) returns (long double)x.
  43  */
  44 union longdouble
  45 _Q_dtoq(double x)
  46
  47 #endif /* __sparcv9 */
  48
  49 {
  50 #ifndef __sparcv9
  51         union longdouble        z;
  52 #endif
  53         union xdouble           u;
  54         unsigned int            m, lhi, llo, fsr;
  55
  56         /* extract the exponent */
  57         u.d = x;
  58         m = ((u.l.hi & 0x7ff00000) >> 4) + 0x3c000000;
  59         if (m == 0x3c000000) {
  60                 /* x is zero or denormal */
  61                 if ((u.l.hi & 0xfffff) | u.l.lo) {
  62                         /* x is denormal, normalize it */
  63                         m = 0x3c010000;
  64                         lhi = u.l.hi & 0xfffff;
  65                         llo = u.l.lo;
  66                         do {
  67                                 lhi = (lhi << 1) | (llo >> 31);
  68                                 llo <<= 1;
  69                                 m -= 0x10000;
  70                         } while ((lhi & 0x7ff00000) == 0);
  71                         u.l.hi = (u.l.hi & 0x80000000) | lhi;
  72                         u.l.lo = llo;
  73                 } else {
  74                         m = 0;
  75                 }
  76         } else if (m == 0x43ff0000) {
  77                 /* x is inf or nan */
  78                 m = 0x7fff0000;
  79                 if (((u.l.hi & 0x7ffff) | u.l.lo) && (u.l.hi & 0x80000) == 0) {
  80                         /* snan, signal invalid */
  81                         __quad_getfsrp(&fsr);
  82                         if (fsr & FSR_NVM) {
  83                                 __quad_fdtoq(&x, &Z);
  84                                 QUAD_RETURN(Z);
  85                         } else {
  86                                 fsr = (fsr & ~FSR_CEXC) | FSR_NVA | FSR_NVC;
  87                                 __quad_setfsrp(&fsr);
  88                         }
  89                         u.l.hi |= 0x80000;
  90                 }
  91         }
  92         Z.l.msw = m | (u.l.hi & 0x80000000) | ((u.l.hi & 0xffff0) >> 4);
  93         Z.l.frac2 = (u.l.hi << 28) | (u.l.lo >> 4);
  94         Z.l.frac3 = u.l.lo << 28;
  95         Z.l.frac4 = 0;
  96         QUAD_RETURN(Z);
  97 }