changed: Big::AboutEqual()
it lacks the case when either 'this' or 'ss2' is zero git-svn-id: svn://ttmath.org/publicrep/ttmath/trunk@205 e52654a7-88a9-db11-a3e9-0013d4bc506e
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@ -19,9 +19,6 @@ Version 0.9.0 prerelease (2009.10.03):
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* added: multithread support for Big<> class
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you should compile with TTMATH_MULTITHREADS
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and use TTMATH_MULTITHREADS_HELPER macro somewhere in your *.cpp file
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* added: Big::AboutEqual(const Big<exp,man> & ss2, int nBitsToIgnore)
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Big::AboutEqualWithoutSign(const Big<exp,man> & ss2, int nBitsToIgnore)
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the last nBitsToIgnore bits from mantissas will be skipped when comparing
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* added: x86_64 asm code for Microsoft Visual compiler
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file: ttmathuint_x86_64_msvc.asm
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(this file should be compiled first because MS VC doesn't support inline assembler in x86_64 mode)
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@ -4169,19 +4169,65 @@ public:
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// two last bits are different
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if( a.AboutEqualWithoutSign(b, 2) ) // the result is true
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std::cout << "true" << std::endl;
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*/
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bool AboutEqualWithoutSign(const Big<exp,man> & ss2, uint nBitsToIgnore) const
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{
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/* not finished, should be added testing then exponents are different about one */
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// there is no sense to ignore the whole mantissas
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TTMATH_ASSERT( nBitsToIgnore < man*TTMATH_BITS_PER_UINT )
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***warning broken*** doesn't work if 'this' or 'ss2' is zero
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*/
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bool AboutEqualWithoutSign(const Big<exp,man> & ss2, uint ignore_bits = 4) const
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{
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TTMATH_ASSERT( ignore_bits < man*TTMATH_BITS_PER_UINT )
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if( IsZero() && ss2.IsZero() )
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return true;
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uint words = nBitsToIgnore / TTMATH_BITS_PER_UINT;
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uint bits = nBitsToIgnore % TTMATH_BITS_PER_UINT;
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if( exponent == ss2.exponent )
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return AboutEqualExpEqual(mantissa, ss2.mantissa, ignore_bits);
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UInt<exp> exp_diff;
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exp_diff = exponent;
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exp_diff.Sub(ss2.exponent);
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if( exp_diff == 1 )
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{
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// exponent is > ss2.exponent
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UInt<man> man_diff(mantissa);
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UInt<man> man_temp(ss2.mantissa);
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man_temp.Rcr(1, 0);
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man_diff.Sub(man_temp);
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return AboutEqualZero(man_diff, ignore_bits);
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}
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else
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if( exp_diff == -1 )
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{
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// exponent is < ss2.exponent
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UInt<man> man_diff(ss2.mantissa);
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UInt<man> man_temp(mantissa);
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man_temp.Rcr(1, 0);
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man_diff.Sub(man_temp);
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return AboutEqualZero(man_diff, ignore_bits);
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}
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// exp_diff is different from zero, one or minus one
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return false;
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}
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private:
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/*!
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an auxiliary method for calculating AboutEqualWithoutSign()
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we're using it when exponent is equal ss2.exponent
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*/
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bool AboutEqualExpEqual(const UInt<man> & man1, const UInt<man> & man2, uint ignore_bits) const
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{
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uint words = ignore_bits / TTMATH_BITS_PER_UINT;
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uint bits = ignore_bits % TTMATH_BITS_PER_UINT;
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uint i;
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if( bits == 0 )
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@ -4193,48 +4239,55 @@ public:
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i = words + 1;
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uint mask = TTMATH_UINT_MAX_VALUE << bits;
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if( (mantissa.table[words] & mask) != (ss2.mantissa.table[words] & mask) )
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if( (man1.table[words] & mask) != (man2.table[words] & mask) )
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return false;
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}
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for( ; i<man ; ++i )
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{
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if( mantissa.table[i] != ss2.mantissa.table[i] )
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if( man1.table[i] != man2.table[i] )
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return false;
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}
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if( exponent != ss2.exponent )
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return false;
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return true;
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}
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/*!
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this method compares this and ss2 by ingoring some nBitsToIgnore last bits from mantissas
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if nBitsToIgnore is 0 then the method is equivalent to operator==() operator
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(we don't check the NaN flag)
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this method is similar to AboutEqualWithoutSign but the signs are checked now
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sample:
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Big<1,1> a, b;
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a = "456.6789";
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b = "456.678901";
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// binary a: 111001000.10101101110011000101111
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// binary b: 111001000.10101101110011000110111
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// five last bits are different
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if( a.AboutEqual(b, 5) ) // the result is true
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std::cout << "true" << std::endl;
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an auxiliary method for calculating AboutEqualWithoutSign()
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*/
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bool AboutEqual(const Big<exp,man> & ss2, uint nBitsToIgnore) const
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bool AboutEqualZero(const UInt<man> & man_diff, uint ignore_bits) const
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{
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if( IsSign() != ss2.IsSign() )
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return false;
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uint words = ignore_bits / TTMATH_BITS_PER_UINT;
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uint bits = ignore_bits % TTMATH_BITS_PER_UINT;
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uint i;
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return AboutEqualWithoutSign(ss2, nBitsToIgnore);
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if( bits == 0 )
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{
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i = words;
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}
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else
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{
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i = words + 1;
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uint mask = TTMATH_UINT_MAX_VALUE << bits;
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if( (man_diff.table[words] & mask) != 0 )
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return false;
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}
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for( ; i<man ; ++i )
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{
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if( man_diff.table[i] != 0 )
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return false;
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}
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return true;
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}
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public:
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bool operator<(const Big<exp,man> & ss2) const
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{
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if( IsSign() && !ss2.IsSign() )
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