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  1.  
  2. /*
  3.  * Copyright (C) 2005 Josef Cejka
  4.  * All rights reserved.
  5.  *
  6.  * Redistribution and use in source and binary forms, with or without
  7.  * modification, are permitted provided that the following conditions
  8.  * are met:
  9.  *
  10.  * - Redistributions of source code must retain the above copyright
  11.  *   notice, this list of conditions and the following disclaimer.
  12.  * - Redistributions in binary form must reproduce the above copyright
  13.  *   notice, this list of conditions and the following disclaimer in the
  14.  *   documentation and/or other materials provided with the distribution.
  15.  * - The name of the author may not be used to endorse or promote products
  16.  *   derived from this software without specific prior written permission.
  17.  *
  18.  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  19.  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  20.  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  21.  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  22.  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  23.  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  24.  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  25.  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  26.  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  27.  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  28.  */
  29.  
  30. #include<softfloat.h>
  31.  
  32.  
  33. float __addsf3(float a, float b)
  34. {
  35.     float32 fa, fb;
  36.     a.f=a;
  37.     b.f=b;
  38.     if (a.parts.sign!=b.parts.sign) return subFloat32(a,b).f;
  39.     return addFloat32(a,b).f;
  40. };
  41.  
  42. float __subsf3(float a, float b)
  43. {
  44.     float32 fa, fb;
  45.     a.f=a;
  46.     b.f=b;
  47.     if (a.parts.sign!=b.parts.sign) return addFloat32(a,b).f;
  48.     return subFloat32(a,b).f;
  49. };
  50.  
  51. float __negsf2(float a)
  52. {
  53.     float32 fa;
  54.     fa.f=a;
  55.     fa.parts.sign=!fa.parts.sign;
  56.     return fa.f;
  57. };
  58.  
  59. double __negdf2(double a)
  60. {
  61.     float64 fa;
  62.     fa.f=a;
  63.     fa.parts.sign=!fa.parts.sign;
  64.     return fa.f;
  65. };
  66.  
  67. float32 addFloat32(float32 a, float32 b)
  68. {
  69.     __u32 expdiff;
  70.     __u32 exp1,exp2,mant1,mant2;
  71.    
  72.     expdiff=a.parts.exp - b.parts.exp;
  73.     if (expdiff<0) {
  74.         if (isFloat32NaN(a)) {
  75.             //TODO: fix it
  76.             return a;
  77.         };
  78.  
  79.         mant1=b.parts.mantisa;
  80.         exp1=b.parts.exp;
  81.         mant2=a.parts.mantisa;
  82.         exp2=a.parts.exp;
  83.         expdiff*=-1;
  84.     } else {
  85.         if (isFloat32NaN(b)) {
  86.             //TODO: fix it
  87.             return b;
  88.         };
  89.         mant1=a.parts.mantisa;
  90.         exp1=a.parts.exp;
  91.         mant2=b.parts.mantisa;
  92.         exp2=b.parts.exp;
  93.     };
  94.  
  95.     // create some space for rounding
  96.     mant1<<=6;
  97.     mant2<<=6;
  98.    
  99.     if (exp1!=0) {
  100.         mant1|=0x20000000; //add hidden bit
  101.     };
  102.    
  103.     if (exp2==0) {
  104.         --expdiff; 
  105.     } else {
  106.         mant2|=0x20000000; //hidden bit
  107.     };
  108.    
  109.    
  110.     if (expdiff>24) {
  111.         goto done;
  112.     };
  113.    
  114.     mant2>>=expdiff;
  115.     mant1+=mant2;
  116. done:
  117.     //TODO: round mant1
  118.     a.parts.exp=exp1;
  119.     a.parts.mantisa=mant1>>6;
  120.     return a;
  121. };
  122.  
  123. float32 subFloat32(float32 a, float32 b)
  124. {
  125.    
  126.    
  127. };
  128.  
  129. inline int isFloat32NaN(float32 f)
  130. {   /* NaN : exp = 0xff and nonzero mantisa */
  131.     float32 fa;
  132.     fa.f=f;
  133.     return ((fa.parts.exp==0xFF)&&(fa.parts.mantisa));
  134. };
  135.  
  136. inline int isFloat32SigNaN(float32 f)
  137. {   /* SigNaN : exp = 0xff mantisa = 1xxxxx..x (binary), where at least one x is nonzero */
  138.     float32 fa;
  139.     fa.f=f;
  140.     return ((fa.parts.exp==0xFF)&&(fa.parts.mantisa>0x400000));
  141. };
  142.  
  143.