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  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.         result.parts.mantisa = mant;
  63.     };
  64.    
  65.     return result;
  66.    
  67. };
  68.  
  69. float32 convertFloat64ToFloat32(float64 a)
  70. {
  71.     float32 result;
  72.     __s32 exp;
  73.     __u64 mant;
  74.    
  75.     result.parts.sign = a.parts.sign;
  76.    
  77.     if (isFloat64NaN(a)) {
  78.        
  79.         result.parts.exp = 0xFF;
  80.        
  81.         if (isFloat64SigNaN(a)) {
  82.             result.parts.mantisa = 0x800000; /* set first bit of mantisa nonzero */
  83.             return result;
  84.         }
  85.    
  86.         result.parts.mantisa = 0x1; /* mantisa nonzero but its first bit is zero */
  87.         return result;
  88.     };
  89.  
  90.     if (isFloat64Infinity(a)) {
  91.         result.parts.mantisa = 0;
  92.         result.parts.exp = 0xFF;
  93.         return result;
  94.     };
  95.  
  96.     exp = (int)a.parts.exp - FLOAT64_BIAS + FLOAT32_BIAS;
  97.    
  98.     if (exp >= 0xFF) {
  99.         /*FIXME: overflow*/
  100.         result.parts.mantisa = 0;
  101.         result.parts.exp = 0xFF;
  102.         return result;
  103.        
  104.     } else if (exp <= 0 ) {
  105.        
  106.         /* underflow or denormalized */
  107.        
  108.         result.parts.exp = 0;
  109.        
  110.         exp *= -1; 
  111.        
  112.         if (exp > FLOAT32_MANTISA_SIZE ) {
  113.             /* FIXME: underflow */
  114.             result.parts.mantisa = 0;
  115.             return result;
  116.         };
  117.        
  118.         /* denormalized */
  119.        
  120.         mant = result.parts.mantisa >> 1;
  121.         mant |= 0x10000000000000ll; /* denormalize and set hidden bit */
  122.        
  123.         while (exp > 0) {
  124.             --exp;
  125.             mant >>= 1;
  126.         };
  127.         result.parts.mantisa = mant;
  128.        
  129.         return result;
  130.     };
  131.  
  132.     result.parts.exp = exp;
  133.     result.parts.mantisa = a.parts.mantisa >> (FLOAT64_MANTISA_SIZE - FLOAT32_MANTISA_SIZE);
  134.     return result;
  135. };
  136.  
  137.