WebSVN – HelenOS-historic – Diff – /uspace/trunk/softfloat/generic/arithmetic.c

 /*
  * Copyright (C) 2005 Josef Cejka
  * All rights reserved.
+ *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
+ *
  * - Redistributions of source code must retain the above copyright
  *   notice, this list of conditions and the following disclaimer.
  * - Redistributions in binary form must reproduce the above copyright
  *   notice, this list of conditions and the following disclaimer in the
  *   documentation and/or other materials provided with the distribution.
  * - The name of the author may not be used to endorse or promote products
  *   derived from this software without specific prior written permission.
+ *
  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 #include<sftypes.h>
 #include<arithmetic.h>
 #include<comparison.h>
 /** Add two Float32 numbers with same signs
  */
 float32 addFloat32(float32 a, float32 b)
+{
     int expdiff;
     __u32 exp1,exp2,mant1,mant2;
     expdiff=a.parts.exp - b.parts.exp;
     if (expdiff<0) {
         if (isFloat32NaN(b)) {
             //TODO: fix SigNaN
             if (isFloat32SigNaN(b)) {
             };
             return b;
         };
         if (b.parts.exp==0xFF) {
             return b;
+        }
         mant1=b.parts.mantisa;
         exp1=b.parts.exp;
         mant2=a.parts.mantisa;
         exp2=a.parts.exp;
         expdiff*=-1;
     } else {
         if (isFloat32NaN(a)) {
             //TODO: fix SigNaN
             if ((isFloat32SigNaN(a))||(isFloat32SigNaN(b))) {
             };
             return a;
         };
         if (a.parts.exp==0xFF) {
             return a;
+        }
         mant1=a.parts.mantisa;
         exp1=a.parts.exp;
         mant2=b.parts.mantisa;
         exp2=b.parts.exp;
     };
     if (exp1==0) {
         //both are denormalized
         mant1+=mant2;
         if (mant1&0xF00000) {
             a.parts.exp=1;
         };
         a.parts.mantisa=mant1;
         return a;
     };
     // create some space for rounding
     mant1<<=6;
     mant2<<=6;
     mant1|=0x20000000; //add hidden bit
     if (exp2==0) {
         --expdiff;
     } else {
         mant2|=0x20000000; //hidden bit
     };
     if (expdiff>24) {
          goto done;
          };
     mant2>>=expdiff;
     mant1+=mant2;
 done:
     if (mant1&0x40000000) {
         ++exp1;
         mant1>>=1;
     };
     //rounding - if first bit after mantisa is set then round up
     mant1+=0x20;
     if (mant1&0x40000000) {
         ++exp1;
         mant1>>=1;
     };
     a.parts.exp=exp1;
     a.parts.mantisa = ((mant1&(~0x20000000))>>6); /*Clear hidden bit and shift */
     return a;
 };
 /** Subtract two float32 numbers with same signs
  */
 float32 subFloat32(float32 a, float32 b)
+{
     int expdiff;
     __u32 exp1,exp2,mant1,mant2;
     float32 result;
     result.f = 0;
     expdiff=a.parts.exp - b.parts.exp;
     if ((expdiff<0)||((expdiff==0)&&(a.parts.mantisa<b.parts.mantisa))) {
         if (isFloat32NaN(b)) {
             //TODO: fix SigNaN
             if (isFloat32SigNaN(b)) {
             };
             return b;
         };
         if (b.parts.exp==0xFF) {
             b.parts.sign=!b.parts.sign; /* num -(+-inf) = -+inf */
             return b;
+        }
         result.parts.sign = !a.parts.sign;
         mant1=b.parts.mantisa;
         exp1=b.parts.exp;
         mant2=a.parts.mantisa;
         exp2=a.parts.exp;
         expdiff*=-1;
     } else {
         if (isFloat32NaN(a)) {
             //TODO: fix SigNaN
             if ((isFloat32SigNaN(a))||(isFloat32SigNaN(b))) {
             };
             return a;
         };
         if (a.parts.exp==0xFF) {
             if (b.parts.exp==0xFF) {
                 /* inf - inf => nan */
                 //TODO: fix exception
                 result.binary = FLOAT32_NAN;
                 return result;
             };
             return a;
+        }
         result.parts.sign = a.parts.sign;
         mant1=a.parts.mantisa;
         exp1=a.parts.exp;
         mant2=b.parts.mantisa;
         exp2=b.parts.exp;
     };
     if (exp1==0) {
         //both are denormalized
         result.parts.mantisa=mant1-mant2;
         if (result.parts.mantisa>mant1) {
             //TODO: underflow exception
             return result;
         };
         result.parts.exp=0;
         return result;
     };
     // create some space for rounding
     mant1<<=6;
     mant2<<=6;
     mant1|=0x20000000; //add hidden bit
     if (exp2==0) {
         --expdiff;
     } else {
         mant2|=0x20000000; //hidden bit
     };
     if (expdiff>24) {
          goto done;
          };
     mant1 = mant1-(mant2>>expdiff);
 done:
     //TODO: find first nonzero digit and shift result and detect possibly underflow
     while ((exp1>0)&&(!(mant1&0x20000000))) {
         exp1--;
         mant1 <<= 1;
         if(mant1 == 0) {
             /* Realy is it an underflow? ... */
-            //TODO: fix underflow
+            /* TODO: fix underflow */
         };
     };
     //rounding - if first bit after mantisa is set then round up
     mant1 += 0x20;
     if (mant1&0x40000000) {
         ++exp1;
         mant1>>=1;
     };
     result.parts.mantisa = ((mant1&(~0x20000000))>>6); /*Clear hidden bit and shift */
     result.parts.exp = exp1;
     return result;
 };
+/** Multiply two 32 bit float numbers
+ *
+ */
+float32 mulFloat32(float32 a, float32 b)
+{
+    float32 result;
+    __u64 mant1, mant2;
+    __s32 exp;
+    result.parts.sign = a.parts.sign ^ b.parts.sign;
+    if ((isFloat32NaN(a))||(isFloat32NaN(b))) {
+        /* TODO: fix SigNaNs */
+        if (isFloat32SigNaN(a)) {
+            result.parts.mantisa = a.parts.mantisa;
+            result.parts.exp = a.parts.exp;
+            return result;
+        };
+        if (isFloat32SigNaN(b)) { /* TODO: fix SigNaN */
+            result.parts.mantisa = b.parts.mantisa;
+            result.parts.exp = b.parts.exp;
+            return result;
+        };
+        /* set NaN as result */
+        result.parts.mantisa = 0x1;
+        result.parts.exp = 0xFF;
+        return result;
+    };
+    if (isFloat32Infinity(a)) {
+        if (isFloat32Zero(b)) {
+            /* FIXME: zero * infinity */
+            result.parts.mantisa = 0x1;
+            result.parts.exp = 0xFF;
+            return result;
+        }
+        result.parts.mantisa = a.parts.mantisa;
+        result.parts.exp = a.parts.exp;
+        return result;
+    }
+    if (isFloat32Infinity(b)) {
+        if (isFloat32Zero(a)) {
+            /* FIXME: zero * infinity */
+            result.parts.mantisa = 0x1;
+            result.parts.exp = 0xFF;
+            return result;
+        }
+        result.parts.mantisa = b.parts.mantisa;
+        result.parts.exp = b.parts.exp;
+        return result;
+    }
+    /* exp is signed so we can easy detect underflow */
+    exp = a.parts.exp + b.parts.exp;
+    exp -= FLOAT32_BIAS;
+    if (exp >= 0xFF ) {
+        /* FIXME: overflow */
+        /* set infinity as result */
+        result.parts.mantisa = 0x0;
+        result.parts.exp = 0xFF;
+        return result;
+    };
+    if (exp < 0) {
+        /* FIXME: underflow */
+        /* return signed zero */
+        result.parts.mantisa = 0x0;
+        result.parts.exp = 0x0;
+        return result;
+    };
+    mant1 = a.parts.mantisa;
+    if (a.parts.exp>0) {
+        mant1 |= 0x800000;
+    } else {
+        ++exp;
+    };
+    mant2 = b.parts.mantisa;
+    if (b.parts.exp>0) {
+        mant2 |= 0x800000;
+    } else {
+        ++exp;
+    };
+    mant1 <<= 1; /* one bit space for rounding */
+    mant1 = mant1 * mant2;
+/* round and return */
+    while ((exp < 0xFF )&&(mant1 > 0x1FFFFFF )) { /* 0xFFFFFF is 23 bits of mantisa + one more for hidden bit (all shifted 1 bit left)*/
+        ++exp;
+        mant1 >>= 1;
+    };
+    /* rounding */
+    //++mant1; /* FIXME: not works - without it is ok */
+    mant1 >>= 1; /* shift off rounding space */
+    if ((exp < 0xFF )&&(mant1 > 0xFFFFFF )) {
+        ++exp;
+        mant1 >>= 1;
+    };
+    if (exp >= 0xFF ) {
+        /* TODO: fix overflow */
+        /* return infinity*/
+        result.parts.exp = 0xFF;
+        result.parts.mantisa = 0x0;
+        return result;
+    }
+    exp -= FLOAT32_MANTISA_SIZE;
+    if (exp <= FLOAT32_MANTISA_SIZE) {
+        /* denormalized number */
+        mant1 >>= 1; /* denormalize */
+        while ((mant1 > 0) && (exp < 0)) {
+            mant1 >>= 1;
+            ++exp;
+        };
+        if (mant1 == 0) {
+            /* FIXME : underflow */
+        result.parts.exp = 0;
+        result.parts.mantisa = 0;
+        return result;
+        };
+    };
+    result.parts.exp = exp;
+    result.parts.mantisa = mant1 & 0x7FFFFF;
+    return result;
+};

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(root)/uspace/trunk/softfloat/generic/arithmetic.c – Rev 661 → 688