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 (the "License").
   6  * You may not use this file except in compliance with the License.
   7  *
   8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
   9  * or http://www.opensolaris.org/os/licensing.
  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 2008 Sun Microsystems, Inc.  All rights reserved.
  24  * Use is subject to license terms.
  25  */
  26 
  27 #pragma ident   "%Z%%M% %I%     %E% SMI"
  28 
  29 #include "lint.h"
  30 #include "base_conversion.h"
  31 
  32 /* The following should be coded as inline expansion templates.  */
  33 
  34 /*
  35  * Multiplies two normal or subnormal doubles, returns result and exceptions.
  36  */
  37 double
  38 __mul_set(double x, double y, int *pe) {
  39         extern void _putsw(), _getsw();
  40         int sw;
  41         volatile double z;
  42 
  43         _putsw(0);
  44         /*
  45          * NOTE:  By declaring 'z' volatile above, we intend for the
  46          * compiler to not move this after the _getmxcsr() call, whose results
  47          * are only useful if they immediately follow the multiply.
  48          *
  49          * From the C11 spec:
  50          *
  51          * 134 - A volatile declaration may be used to describe an
  52          * object corresponding to a memory-mapped input/output port
  53          * or an object accessed by an asynchronously interrupting
  54          * function. Actions on objects so declared shall by an
  55          * implementation or reordered except as permitted by the
  56          * rules for evaluating expressions."
  57          */
  58         z = x * y;
  59         _getsw(&sw);
  60         if ((sw & 0x3f) == 0) {
  61                 *pe = 0;
  62         } else {
  63                 /* Result may not be exact. */
  64                 *pe = 1;
  65         }
  66         return (z);
  67 }
  68 
  69 /*
  70  * Divides two normal or subnormal doubles x/y, returns result and exceptions.
  71  */
  72 double
  73 __div_set(double x, double y, int *pe) {
  74         extern void _putsw(), _getsw();
  75         int sw;
  76         volatile double z;
  77 
  78         _putsw(0);
  79         /* NOTE:  See __mul_set() above, same principle applies here. */
  80         z = x / y;
  81         _getsw(&sw);
  82         if ((sw & 0x3f) == 0) {
  83                 *pe = 0;
  84         } else {
  85                 *pe = 1;
  86         }
  87         return (z);
  88 }
  89 
  90 double
  91 __dabs(double *d)
  92 {
  93         /* should use hardware fabs instruction */
  94         return ((*d < 0.0) ? -*d : *d);
  95 }
  96 
  97 /*
  98  * Returns IEEE mode/status and
  99  * sets up standard environment for base conversion.
 100  */
 101 void
 102 __get_ieee_flags(__ieee_flags_type *b) {
 103         extern void _getcw(), _getsw(), _putcw();
 104         int cw;
 105 
 106         _getcw(&cw);
 107         b->mode = cw;
 108         _getsw(&b->status);
 109         /*
 110          * set CW to...
 111          * RC (bits 10:11)      0 == round to nearest even
 112          * PC (bits 8:9)        2 == round to double
 113          * EM (bits 0:5)        0x3f == all exception trapping masked off
 114          */
 115         cw = (cw & ~0xf3f) | 0x23f;
 116         _putcw(cw);
 117 }
 118 
 119 /*
 120  * Restores previous IEEE mode/status
 121  */
 122 void
 123 __set_ieee_flags(__ieee_flags_type *b) {
 124         extern void _putcw(), _putsw();
 125 
 126         _putcw(b->mode);
 127         _putsw(b->status);
 128 }