Subversion Repositories HelenOS-historic

Rev

Rev 697 | Rev 857 | Go to most recent revision | Blame | Compare with Previous | Last modification | View Log | Download | RSS feed

  1. /*
  2.  * Copyright (C) 2005 Josef Cejka
  3.  * All rights reserved.
  4.  *
  5.  * Redistribution and use in source and binary forms, with or without
  6.  * modification, are permitted provided that the following conditions
  7.  * are met:
  8.  *
  9.  * - Redistributions of source code must retain the above copyright
  10.  *   notice, this list of conditions and the following disclaimer.
  11.  * - Redistributions in binary form must reproduce the above copyright
  12.  *   notice, this list of conditions and the following disclaimer in the
  13.  *   documentation and/or other materials provided with the distribution.
  14.  * - The name of the author may not be used to endorse or promote products
  15.  *   derived from this software without specific prior written permission.
  16.  *
  17.  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  18.  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  19.  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  20.  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  21.  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  22.  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  23.  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  24.  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  25.  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  26.  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  27.  */
  28.  
  29. #include "sftypes.h"
  30. #include "conversion.h"
  31.  
  32. float64 convertFloat32ToFloat64(float32 a)
  33. {
  34.     float64 result;
  35.     __u64 mant;
  36.    
  37.     result.parts.sign = a.parts.sign;
  38.     result.parts.mantisa = a.parts.mantisa;
  39.     result.parts.mantisa <<= (FLOAT64_MANTISA_SIZE - FLOAT32_MANTISA_SIZE );
  40.    
  41.     if ((isFloat32Infinity(a))||(isFloat32NaN(a))) {
  42.         result.parts.exp = 0x7FF;
  43.         /* TODO; check if its correct for SigNaNs*/
  44.         return result;
  45.     };
  46.    
  47.     result.parts.exp = a.parts.exp + ( (int)FLOAT64_BIAS - FLOAT32_BIAS );
  48.     if (a.parts.exp == 0) {
  49.         /* normalize denormalized numbers */
  50.  
  51.         if (result.parts.mantisa == 0ll) { /* fix zero */
  52.             result.parts.exp = 0ll;
  53.             return result;
  54.         }
  55.            
  56.         mant = result.parts.mantisa;
  57.        
  58.         while (!(mant & (0x10000000000000ll))) {
  59.             mant <<= 1;
  60.             --result.parts.exp;
  61.         };
  62.        
  63.         ++result.parts.exp;
  64.         result.parts.mantisa = mant;
  65.     };
  66.    
  67.     return result;
  68.    
  69. };
  70.  
  71. float32 convertFloat64ToFloat32(float64 a)
  72. {
  73.     float32 result;
  74.     __s32 exp;
  75.     __u64 mant;
  76.    
  77.     result.parts.sign = a.parts.sign;
  78.    
  79.     if (isFloat64NaN(a)) {
  80.        
  81.         result.parts.exp = 0xFF;
  82.        
  83.         if (isFloat64SigNaN(a)) {
  84.             result.parts.mantisa = 0x800000; /* set first bit of mantisa nonzero */
  85.             return result;
  86.         }
  87.    
  88.         result.parts.mantisa = 0x1; /* mantisa nonzero but its first bit is zero */
  89.         return result;
  90.     };
  91.  
  92.     if (isFloat64Infinity(a)) {
  93.         result.parts.mantisa = 0;
  94.         result.parts.exp = 0xFF;
  95.         return result;
  96.     };
  97.  
  98.     exp = (int)a.parts.exp - FLOAT64_BIAS + FLOAT32_BIAS;
  99.    
  100.     if (exp >= 0xFF) {
  101.         /*FIXME: overflow*/
  102.         result.parts.mantisa = 0;
  103.         result.parts.exp = 0xFF;
  104.         return result;
  105.        
  106.     } else if (exp <= 0 ) {
  107.        
  108.         /* underflow or denormalized */
  109.        
  110.         result.parts.exp = 0;
  111.        
  112.         exp *= -1; 
  113.         if (exp > FLOAT32_MANTISA_SIZE ) {
  114.             /* FIXME: underflow */
  115.             result.parts.mantisa = 0;
  116.             return result;
  117.         };
  118.        
  119.         /* denormalized */
  120.        
  121.         mant = a.parts.mantisa;
  122.         mant |= 0x10000000000000ll; /* denormalize and set hidden bit */
  123.        
  124.         mant >>= (FLOAT64_MANTISA_SIZE - FLOAT32_MANTISA_SIZE + 1);
  125.        
  126.         while (exp > 0) {
  127.             --exp;
  128.             mant >>= 1;
  129.         };
  130.         result.parts.mantisa = mant;
  131.        
  132.         return result;
  133.     };
  134.  
  135.     result.parts.exp = exp;
  136.     result.parts.mantisa = a.parts.mantisa >> (FLOAT64_MANTISA_SIZE - FLOAT32_MANTISA_SIZE);
  137.     return result;
  138. };
  139.  
  140.