Corrected issue with particular sequences of zeros.

No more known division issues.

2 files changed, 48 insertions, 20 deletions

diff --git a/src/config.h b/src/config.h
new file mode 100644
index 0000000..00fb067
--- /dev/null
+++ b/src/config.h
@@ -0,0 +1,8 @@
+#ifndef CONFIG_H

+#define CONFIG_H

+

+#define DEBUG_DIVIDE false

+#define DBS( s, x ) if( DEBUG_ ##s ) { x; } (void)0

+

+

+#endif

diff --git a/src/number.cpp b/src/number.cpp
index 9a7da17..328cb58 100644
--- a/src/number.cpp
+++ b/src/number.cpp
@@ -1,8 +1,20 @@
+#include "config.h"

 #include "number.h"

 

 #include <bu/sio.h>

 #include <math.h>

 

+// Enjoy the majisty of my magic floating point literal!

+// This tells us how many bits we'll need per digit to represent a particular

+// radix.  You can figure out how many digits any number will take up in any

+// radix with the following:

+//

+// ceiling(ln( num ) / ln( radix ))

+//

+// As long as the base of the logs are the same it doesn't matter what the base

+// is, it cancels out, so we don't have to be particular.  But we're always

+// looking for the largest number in a radix to be stored in binary, so the

+// denominator is always the same, so I precomputed it.

 #define RadixToBits( x ) ((int)(log((x))*0xb.8aa3b295c17fp-3+1.0))

 

 Number::Number( int iScale, int iRadix ) :

@@ -392,27 +404,27 @@ void Number::set( int32_t iNum )
 

 void Number::divide( const Number &rhs, Number &q, Number &r ) const

 {

-//    Bu::println("divide: %1 / %2").arg( *this ).arg( rhs );

+    DBS( DIVIDE, Bu::println("divide: %1 / %2").arg( *this ).arg( rhs ) );

 

     // iNumShift is how many digits we've shifted the entire equation,

     // effectively multiplying the numerator and divisor by iRadix*iNumShift

     int iNumShift = rhs.getEffectiveScale();

-//    Bu::println("iNumShift = %1").arg( iNumShift );

+    DBS( DIVIDE, Bu::println("iNumShift = %1").arg( iNumShift ) );

 

     // Setup our divisor, this is important, it should be an integer to make

     // things easy, and it won't change once we create it.

     Number nDiv( 0, iRadix );

     for( int j = -iNumShift; j < rhs.aInt.getSize(); j++ )

     {

-//        Bu::println("  -> '%1'").arg( rhs.digit( j ) );

+        DBS( DIVIDE, Bu::println("  -> '%1'").arg( rhs.digit( j ) ) );

         nDiv.aInt.append( rhs.digit( j ) );

     }

-//    Bu::println("New divisor: %1").arg( nDiv );

+    DBS( DIVIDE, Bu::println("New divisor: %1").arg( nDiv ) );

 

     // Anchor is the position in the output the new digit will appear.

     // This also tells us where the ones place will be in our new numerator.

     int iAnchor = (aInt.getSize()+iNumShift)-nDiv.aInt.getSize();

-//    Bu::println("Anchor: %1").arg( iAnchor );

+    DBS( DIVIDE, Bu::println("Anchor: %1").arg( iAnchor ) );

     

     // Setup our output variables

     q.iRadix = r.iRadix = iRadix;

@@ -433,22 +445,30 @@ void Number::divide( const Number &rhs, Number &q, Number &r ) const
     for( int j = iAnchor-iNumShift;

         nNum.aInt.getSize() < nDiv.aInt.getSize(); j++ )

     {

-//        Bu::println("  ->[%1] '%2'").arg( j ).arg( digit(j) );

+        DBS( DIVIDE, Bu::println("  ->[%1] '%2'").arg( j ).arg( digit(j) ) );

         nNum.aInt.append( digit( j ) );

     }

-//    Bu::println("New numerator: %1").arg( nNum );

+    DBS( DIVIDE, Bu::println("New numerator: %1").arg( nNum ) );

     while( iAnchor >= -iScale && (!nNum.isZero() || iAnchor > 0)) // division loop

     {

         // As long as the numerator is smaller than the divisor we keep

         // including new digits.

-        while( nNum < nDiv )

+        while( nNum.aInt.getSize() < nDiv.aInt.getSize() ||

+               nNum < nDiv )

         {

             iAnchor--;

-            nNum.aInt.insert( 0, digit(iAnchor-iNumShift) );

-//            Bu::println("Numerator too small, new numerator: %1").arg( nNum );

+            int iDig = digit(iAnchor-iNumShift);

+            if( nNum.aInt.getSize() == 0 && iDig == 0 )

+            {

+                if( iAnchor < -iScale )

+                    break;

+                continue;

+            }

+            nNum.aInt.insert( 0, iDig );

+            DBS( DIVIDE, Bu::println("Numerator too small, new numerator: %1").arg( nNum ) );

         }

 

-//        Bu::println("  New anchor: %1 vs iScale = %2").arg( iAnchor ).arg( iScale );

+        DBS( DIVIDE, Bu::println("  New anchor: %1 vs iScale = %2").arg( iAnchor ).arg( iScale ) );

         if( iAnchor < 0 && -1-iAnchor >= iScale )

             break;

         

@@ -456,11 +476,11 @@ void Number::divide( const Number &rhs, Number &q, Number &r ) const
         int iCount = 0;

         for(;nNum >= nDiv; iCount++ )

         {

-//            Bu::print(" ==> step %3: %1 - %2 = ").arg( nNum ).arg( nDiv ).arg( iCount );

+            DBS( DIVIDE, Bu::print(" ==> step %3: %1 - %2 = ").arg( nNum ).arg( nDiv ).arg( iCount ) );

             nNum = nNum - nDiv;

-//            Bu::println("%1").arg( nNum );

+            DBS( DIVIDE, Bu::println("%1").arg( nNum ) );

         }

-//        Bu::println("Total steps: %1").arg( iCount );

+        DBS( DIVIDE, Bu::println("Total steps: %1").arg( iCount ) );

 

         if( iAnchor >= 0 )

         {

@@ -481,15 +501,15 @@ void Number::divide( const Number &rhs, Number &q, Number &r ) const
             r.aInt.append( nNum.aInt[j] );

         int jtop = 0;

         for(; nNum.aInt[jtop] == 0; jtop++ ) { }

-//        Bu::println("Computing remainder fraction from %1 to %2")

-//            .arg( -iAnchor-1 ).arg( jtop );

+        DBS( DIVIDE, Bu::println("Computing remainder fraction from %1 to %2")

+            .arg( -iAnchor-1 ).arg( jtop ) );

         r.aFrac.clear();

         for( int j = -iAnchor-1, k = 0; j >= jtop && k < r.iScale; j--, k++ )

         {

             if( j < nNum.aInt.getSize() )

             {

                 r.aFrac.set( k, nNum.aInt[j] );

-//                Bu::println("setting %1 to %2").arg( k ).arg( nNum.aInt[j] );

+                DBS( DIVIDE, Bu::println("setting %1 to %2").arg( k ).arg( nNum.aInt[j] ) );

             }

         }

     }

@@ -497,9 +517,9 @@ void Number::divide( const Number &rhs, Number &q, Number &r ) const
 //    {

 //        Bu::println("iAnchor: %1").arg( iAnchor );

 //    }

-//    Bu::println("Quotient: %1").arg( q );

-//    Bu::println("Final numerator? %1").arg( nNum );

-//    Bu::println("Remainder? %1").arg( r );  

+    DBS( DIVIDE, Bu::println("Quotient: %1").arg( q ) );

+    DBS( DIVIDE, Bu::println("Final numerator? %1").arg( nNum ) );

+    DBS( DIVIDE, Bu::println("Remainder? %1").arg( r ) );

     

 }