From 2a31049201e9c1ff9f515eb9d144ae392f4b4e5a Mon Sep 17 00:00:00 2001 From: Vadim Zeitlin Date: Fri, 7 Jan 2000 20:35:34 +0000 Subject: [PATCH] added test mode to wxLongLongWx which allowed to find the bug in operator*=() which was breaking wxDateTime - now seems to work git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@5297 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775 --- include/wx/longlong.h | 91 +++++++-- samples/console/console.cpp | 191 +++++++++++++++++-- src/common/longlong.cpp | 367 ++++++++++++++++++++---------------- 3 files changed, 466 insertions(+), 183 deletions(-) diff --git a/include/wx/longlong.h b/include/wx/longlong.h index b2b617a804..d2f1ed26de 100644 --- a/include/wx/longlong.h +++ b/include/wx/longlong.h @@ -25,7 +25,15 @@ #include // for LONG_MAX -// #define wxUSE_LONGLONG_WX 1 // for testing (VZ) +// define this to compile wxLongLongWx in "test" mode: the results of all +// calculations will be compared with the real results taken from +// wxLongLongNative +#define wxLONGLONG_TEST_MODE + +#ifdef wxLONGLONG_TEST_MODE + #define wxUSE_LONGLONG_WX 1 + #define wxUSE_LONGLONG_NATIVE 1 +#endif // wxLONGLONG_TEST_MODE // ---------------------------------------------------------------------------- // decide upon which class we will use @@ -73,8 +81,12 @@ // to disable automatic testing (useful for the test program which defines // both classes) but by default we only use one class #if (defined(wxUSE_LONGLONG_WX) && wxUSE_LONGLONG_WX) || !defined(wxLongLong_t) - #undef wxUSE_LONGLONG_NATIVE - #define wxUSE_LONGLONG_NATIVE 0 + // don't use both classes unless wxUSE_LONGLONG_NATIVE was explicitly set: + // this is useful in test programs nad only there + #ifndef wxUSE_LONGLONG_NATIVE + #define wxUSE_LONGLONG_NATIVE 0 + #endif + class WXDLLEXPORT wxLongLongWx; typedef wxLongLongWx wxLongLong; #else @@ -307,13 +319,32 @@ class WXDLLEXPORT wxLongLongWx public: // ctors // default ctor initializes to 0 - wxLongLongWx() { m_lo = m_hi = 0; } + wxLongLongWx() + { + m_lo = m_hi = 0; + +#ifdef wxLONGLONG_TEST_MODE + m_ll = 0; + + Check(); +#endif // wxLONGLONG_TEST_MODE + } // from long - wxLongLongWx(long l) - { m_lo = l; m_hi = (l < 0 ? -1l : 0l); } + wxLongLongWx(long l) { *this = l; } // from 2 longs wxLongLongWx(long hi, unsigned long lo) - { m_hi = hi; m_lo = lo; } + { + m_hi = hi; + m_lo = lo; + +#ifdef wxLONGLONG_TEST_MODE + m_ll = hi; + m_ll <<= 32; + m_ll |= lo; + + Check(); +#endif // wxLONGLONG_TEST_MODE + } // default copy ctor is ok in both cases @@ -322,7 +353,18 @@ public: // assignment operators // from long wxLongLongWx& operator=(long l) - { m_lo = l; m_hi = (l < 0 ? -1l : 0l); return *this; } + { + m_lo = l; + m_hi = (l < 0 ? -1l : 0l); + +#ifdef wxLONGLONG_TEST_MODE + m_ll = l; + + Check(); +#endif // wxLONGLONG_TEST_MODE + + return *this; + } // from double wxLongLongWx& Assign(double d); // can't have assignment operator from 2 longs @@ -335,12 +377,25 @@ public: // get absolute value wxLongLongWx Abs() const { return wxLongLongWx(*this).Abs(); } - wxLongLongWx& Abs() { if ( m_hi < 0 ) m_hi = -m_hi; return *this; } + wxLongLongWx& Abs() + { + if ( m_hi < 0 ) + m_hi = -m_hi; + +#ifdef wxLONGLONG_TEST_MODE + if ( m_ll < 0 ) + m_ll = -m_ll; + + Check(); +#endif // wxLONGLONG_TEST_MODE + + return *this; + } // convert to long with range checking in the debug mode (only!) long ToLong() const { - wxASSERT_MSG( m_hi == 0l, + wxASSERT_MSG( (m_hi == 0l) || (m_hi == -1l), _T("wxLongLong to long conversion loss of precision") ); return (long)m_lo; @@ -357,10 +412,11 @@ public: wxLongLongWx& operator++(); // post increment operator - wxLongLongWx& operator++(int); + wxLongLongWx& operator++(int) { return ++(*this); } // negation operator wxLongLongWx operator-() const; + wxLongLongWx& Negate(); // subraction wxLongLongWx operator-(const wxLongLongWx& ll) const; @@ -370,7 +426,7 @@ public: wxLongLongWx& operator--(); // post decrement operator - wxLongLongWx& operator--(int); + wxLongLongWx& operator--(int) { return --(*this); } // shifts // left shift @@ -421,13 +477,22 @@ public: friend ostream& operator<<(ostream&, const wxLongLongWx&); #endif // wxUSE_STD_IOSTREAM - void *asArray(void) const; + void *asArray() const; private: // long is at least 32 bits, so represent our 64bit number as 2 longs long m_hi; // signed bit is in the high part unsigned long m_lo; + +#ifdef wxLONGLONG_TEST_MODE + void Check() + { + wxASSERT( (m_ll >> 32) == m_hi && (unsigned long)m_ll == m_lo ); + } + + wxLongLong_t m_ll; +#endif // wxLONGLONG_TEST_MODE }; #endif // wxUSE_LONGLONG_WX diff --git a/samples/console/console.cpp b/samples/console/console.cpp index e0fc63111a..e3c75ec71d 100644 --- a/samples/console/console.cpp +++ b/samples/console/console.cpp @@ -30,14 +30,14 @@ // what to test? //#define TEST_ARRAYS -#define TEST_CMDLINE +//#define TEST_CMDLINE //#define TEST_DIR //#define TEST_LOG //#define TEST_LONGLONG //#define TEST_MIME //#define TEST_STRINGS //#define TEST_THREADS -//#define TEST_TIME +#define TEST_TIME // ============================================================================ // implementation @@ -219,6 +219,19 @@ static void TestMimeEnum() #include #include +// make a 64 bit number from 4 16 bit ones +#define MAKE_LL(x1, x2, x3, x4) wxLongLong((x1 << 16) | x2, (x3 << 16) | x3) + +// get a random 64 bit number +#define RAND_LL() MAKE_LL(rand(), rand(), rand(), rand()) + +#if wxUSE_LONGLONG_NATIVE +inline bool operator==(const wxLongLongWx& a, const wxLongLongNative& b) + { return a.GetHi() == b.GetHi() && a.GetLo() == b.GetLo(); } +inline bool operator==(const wxLongLongNative& a, const wxLongLongWx& b) + { return a.GetHi() == b.GetHi() && a.GetLo() == b.GetLo(); } +#endif // wxUSE_LONGLONG_NATIVE + static void TestSpeed() { static const long max = 100000000; @@ -263,15 +276,76 @@ static void TestSpeed() } } +static void TestLongLongConversion() +{ + puts("*** Testing wxLongLong conversions ***\n"); + + wxLongLong a; + size_t nTested = 0; + for ( size_t n = 0; n < 100000; n++ ) + { + a = RAND_LL(); + +#if wxUSE_LONGLONG_NATIVE + wxLongLongNative b(a.GetHi(), a.GetLo()); + + wxASSERT_MSG( a == b, "conversions failure" ); +#else + puts("Can't do it without native long long type, test skipped."); + + return; +#endif // wxUSE_LONGLONG_NATIVE + + if ( !(nTested % 1000) ) + { + putchar('.'); + fflush(stdout); + } + + nTested++; + } + + puts(" done!"); +} + +static void TestMultiplication() +{ + puts("*** Testing wxLongLong multiplication ***\n"); + + wxLongLong a, b; + size_t nTested = 0; + for ( size_t n = 0; n < 100000; n++ ) + { + a = RAND_LL(); + b = RAND_LL(); + +#if wxUSE_LONGLONG_NATIVE + wxLongLongNative aa(a.GetHi(), a.GetLo()); + wxLongLongNative bb(b.GetHi(), b.GetLo()); + + wxASSERT_MSG( a*b == aa*bb, "multiplication failure" ); +#else // !wxUSE_LONGLONG_NATIVE + puts("Can't do it without native long long type, test skipped."); + + return; +#endif // wxUSE_LONGLONG_NATIVE + + if ( !(nTested % 1000) ) + { + putchar('.'); + fflush(stdout); + } + + nTested++; + } + + puts(" done!"); +} + static void TestDivision() { puts("*** Testing wxLongLong division ***\n"); - #define MAKE_LL(x1, x2, x3, x4) wxLongLong((x1 << 16) | x2, (x3 << 16) | x3) - - // seed pseudo random generator - srand((unsigned)time(NULL)); - wxLongLong q, r; size_t nTested = 0; for ( size_t n = 0; n < 100000; n++ ) @@ -285,8 +359,15 @@ static void TestDivision() q = ll / l; r = ll % l; +#if wxUSE_LONGLONG_NATIVE + wxLongLongNative m(ll.GetHi(), ll.GetLo()); + + wxLongLongNative p = m / l, s = m % l; + wxASSERT_MSG( q == p && r == s, "division failure" ); +#else // !wxUSE_LONGLONG_NATIVE // verify the result wxASSERT_MSG( ll == q*l + r, "division failure" ); +#endif // wxUSE_LONGLONG_NATIVE if ( !(nTested % 1000) ) { @@ -298,10 +379,87 @@ static void TestDivision() } puts(" done!"); - - #undef MAKE_LL } +static void TestAddition() +{ + puts("*** Testing wxLongLong addition ***\n"); + + wxLongLong a, b, c; + size_t nTested = 0; + for ( size_t n = 0; n < 100000; n++ ) + { + a = RAND_LL(); + b = RAND_LL(); + c = a + b; + +#if wxUSE_LONGLONG_NATIVE + wxASSERT_MSG( c == wxLongLongNative(a.GetHi(), a.GetLo()) + + wxLongLongNative(b.GetHi(), b.GetLo()), + "addition failure" ); +#else // !wxUSE_LONGLONG_NATIVE + wxASSERT_MSG( c - b == a, "addition failure" ); +#endif // wxUSE_LONGLONG_NATIVE + + if ( !(nTested % 1000) ) + { + putchar('.'); + fflush(stdout); + } + + nTested++; + } + + puts(" done!"); +} + +static void TestBitOperations() +{ + puts("*** Testing wxLongLong bit operation ***\n"); + + wxLongLong a, c; + size_t nTested = 0; + for ( size_t n = 0; n < 100000; n++ ) + { + a = RAND_LL(); + +#if wxUSE_LONGLONG_NATIVE + for ( size_t n = 0; n < 33; n++ ) + { + wxLongLongNative b(a.GetHi(), a.GetLo()); + + b >>= n; + c = a >> n; + + wxASSERT_MSG( b == c, "bit shift failure" ); + + b = wxLongLongNative(a.GetHi(), a.GetLo()) << n; + c = a << n; + + wxASSERT_MSG( b == c, "bit shift failure" ); + } + +#else // !wxUSE_LONGLONG_NATIVE + puts("Can't do it without native long long type, test skipped."); + + return; +#endif // wxUSE_LONGLONG_NATIVE + + if ( !(nTested % 1000) ) + { + putchar('.'); + fflush(stdout); + } + + nTested++; + } + + puts(" done!"); +} + +#undef MAKE_LL +#undef RAND_LL + #endif // TEST_LONGLONG // ---------------------------------------------------------------------------- @@ -1703,10 +1861,21 @@ int main(int argc, char **argv) #endif // TEST_THREADS #ifdef TEST_LONGLONG + // seed pseudo random generator + srand((unsigned)time(NULL)); + if ( 0 ) + { TestSpeed(); - if ( 1 ) + } + TestMultiplication(); + if ( 0 ) + { TestDivision(); + TestAddition(); + TestLongLongConversion(); + TestBitOperations(); + } #endif // TEST_LONGLONG #ifdef TEST_MIME @@ -1714,7 +1883,7 @@ int main(int argc, char **argv) #endif // TEST_MIME #ifdef TEST_TIME - if ( 0 ) + if ( 1 ) { TestTimeSet(); TestTimeStatic(); diff --git a/src/common/longlong.cpp b/src/common/longlong.cpp index 2dd291fb1c..6a0cc8e315 100644 --- a/src/common/longlong.cpp +++ b/src/common/longlong.cpp @@ -41,7 +41,7 @@ // misc // ---------------------------------------------------------------------------- -void *wxLongLongNative::asArray(void) const +void *wxLongLongNative::asArray() const { static unsigned char temp[8]; @@ -89,110 +89,121 @@ ostream& operator<< (ostream& o, const wxLongLongNative& ll) // assignment wxLongLongWx& wxLongLongWx::Assign(double d) { - if ( fabs(d) <= LONG_MAX ) + bool positive = d >= 0; + d = fabs(d); + if ( d <= LONG_MAX ) { - m_hi = d < 0 ? 1 << (8*sizeof(long) - 1) : 0l; + m_hi = 0; m_lo = (long)d; } else { - wxFAIL_MSG(_T("TODO")); +#if 0 + m_lo = (long)d; + d -= m_lo; + d /= 0x1000; + d /= 0x1000; + d /= 0x100; + m_hi = (long)d; +#else + wxFAIL_MSG(_T("TODO")); +#endif } + if ( !positive ) + m_hi = -m_hi; + +#ifdef wxLONGLONG_TEST_MODE + m_ll = (wxLongLong_t)d; + + Check(); +#endif // wxLONGLONG_TEST_MODE + return *this; } wxLongLongWx wxLongLongWx::operator<<(int shift) const { - if (shift == 0) - return *this; + wxLongLongWx ll(*this); + ll <<= shift; - if (shift < 32) - return wxLongLongWx((m_hi << shift) | (m_lo >> (32 - shift)), - m_lo << shift); - else - return wxLongLongWx(m_lo << (shift - 32), - 0); + return ll; } wxLongLongWx& wxLongLongWx::operator<<=(int shift) { - if (shift == 0) - return *this; + if (shift != 0) + { + if (shift < 32) + { + m_hi <<= shift; + m_hi |= m_lo >> (32 - shift); + m_lo <<= shift; + } + else + { + m_hi = m_lo << (shift - 32); + m_lo = 0; + } + } - if (shift < 32) - { - m_hi <<= shift; - m_hi |= m_lo >> (32 - shift); - m_lo <<= shift; - } - else - { - m_hi = m_lo << (shift - 32); - m_lo = 0; - } +#ifdef wxLONGLONG_TEST_MODE + m_ll <<= shift; + + Check(); +#endif // wxLONGLONG_TEST_MODE return *this; } wxLongLongWx wxLongLongWx::operator>>(int shift) const { - if (shift == 0) - return *this; + wxLongLongWx ll(*this); + ll >>= shift; - if (shift < 32) - return wxLongLongWx(m_hi >> shift, - (m_lo >> shift) | (m_hi << (32 - shift))); - else - return wxLongLongWx((m_hi < 0 ? -1l : 0), - m_hi >> (shift - 32)); + return ll; } wxLongLongWx& wxLongLongWx::operator>>=(int shift) { - if (shift == 0) - return *this; + if (shift != 0) + { + if (shift < 32) + { + m_lo >>= shift; + m_lo |= m_hi << (32 - shift); + m_hi >>= shift; + } + else + { + m_lo = m_hi >> (shift - 32); + m_hi = (m_hi < 0 ? -1L : 0); + } + } - if (shift < 32) - { - m_lo >>= shift; - m_lo |= m_hi << (32 - shift); - m_hi >>= shift; - } - else - { - m_lo = m_hi >> (shift - 32); - m_hi = (m_hi < 0 ? -1L : 0); - } +#ifdef wxLONGLONG_TEST_MODE + m_ll >>= shift; + + Check(); +#endif // wxLONGLONG_TEST_MODE return *this; } wxLongLongWx wxLongLongWx::operator+(const wxLongLongWx& ll) const { - wxLongLongWx temp; + wxLongLongWx res(*this); + res += ll; - temp.m_lo = m_lo + ll.m_lo; - temp.m_hi = m_hi + ll.m_hi; - if ((temp.m_lo < m_lo) || (temp.m_lo < ll.m_lo)) - temp.m_hi++; - - return temp; + return res; } wxLongLongWx wxLongLongWx::operator+(long l) const { - wxLongLongWx temp; + wxLongLongWx res(*this); + res += l; - temp.m_lo = m_lo + l; - - if (l < 0) - temp.m_hi += -1l; - - if ((temp.m_lo < m_lo) || (temp.m_lo < (unsigned long)l)) - temp.m_hi++; - - return temp; + return res; } wxLongLongWx& wxLongLongWx::operator+=(const wxLongLongWx& ll) @@ -205,6 +216,12 @@ wxLongLongWx& wxLongLongWx::operator+=(const wxLongLongWx& ll) if ((m_lo < previous) || (m_lo < ll.m_lo)) m_hi++; +#ifdef wxLONGLONG_TEST_MODE + m_ll += ll.m_ll; + + Check(); +#endif // wxLONGLONG_TEST_MODE + return *this; } @@ -219,6 +236,12 @@ wxLongLongWx& wxLongLongWx::operator+=(long l) if ((m_lo < previous) || (m_lo < (unsigned long)l)) m_hi++; +#ifdef wxLONGLONG_TEST_MODE + m_ll += l; + + Check(); +#endif // wxLONGLONG_TEST_MODE + return *this; } @@ -229,15 +252,11 @@ wxLongLongWx& wxLongLongWx::operator++() if (m_lo == 0) m_hi++; - return *this; -} +#ifdef wxLONGLONG_TEST_MODE + m_ll++; -// post increment -wxLongLongWx& wxLongLongWx::operator++(int) -{ - m_lo++; - if (m_lo == 0) - m_hi++; + Check(); +#endif // wxLONGLONG_TEST_MODE return *this; } @@ -245,28 +264,38 @@ wxLongLongWx& wxLongLongWx::operator++(int) // negation wxLongLongWx wxLongLongWx::operator-() const { - wxLongLongWx temp(~m_hi, ~m_lo); + wxLongLongWx res(*this); + res.Negate(); - temp.m_lo++; - if (temp.m_lo == 0) - temp.m_hi++; + return res; +} - return temp; +wxLongLongWx& wxLongLongWx::Negate() +{ + m_hi = ~m_hi; + m_lo = ~m_lo; + + m_lo++; + if ( m_lo == 0 ) + m_hi++; + +#ifdef wxLONGLONG_TEST_MODE + m_ll = -m_ll; + + Check(); +#endif // wxLONGLONG_TEST_MODE + + return *this; } // subtraction wxLongLongWx wxLongLongWx::operator-(const wxLongLongWx& ll) const { - wxLongLongWx temp; + wxLongLongWx res(*this); + res -= ll; - temp.m_lo = m_lo - ll.m_lo; - temp.m_hi = m_hi - ll.m_hi; - - if (m_lo < ll.m_lo) - temp.m_hi--; - - return temp; + return res; } wxLongLongWx& wxLongLongWx::operator-=(const wxLongLongWx& ll) @@ -279,6 +308,12 @@ wxLongLongWx& wxLongLongWx::operator-=(const wxLongLongWx& ll) if (previous < ll.m_lo) m_hi--; +#ifdef wxLONGLONG_TEST_MODE + m_ll -= ll.m_ll; + + Check(); +#endif // wxLONGLONG_TEST_MODE + return *this; } @@ -289,15 +324,11 @@ wxLongLongWx& wxLongLongWx::operator--() if (m_lo == 0xFFFFFFFF) m_hi--; - return *this; -} +#ifdef wxLONGLONG_TEST_MODE + m_ll--; -// post decrement -wxLongLongWx& wxLongLongWx::operator--(int) -{ - m_lo--; - if (m_lo == 0xFFFFFFFF) - m_hi--; + Check(); +#endif // wxLONGLONG_TEST_MODE return *this; } @@ -346,6 +377,12 @@ wxLongLongWx& wxLongLongWx::operator&=(const wxLongLongWx& ll) m_lo &= ll.m_lo; m_hi &= ll.m_hi; +#ifdef wxLONGLONG_TEST_MODE + m_ll &= ll.m_ll; + + Check(); +#endif // wxLONGLONG_TEST_MODE + return *this; } @@ -354,6 +391,12 @@ wxLongLongWx& wxLongLongWx::operator|=(const wxLongLongWx& ll) m_lo |= ll.m_lo; m_hi |= ll.m_hi; +#ifdef wxLONGLONG_TEST_MODE + m_ll |= ll.m_ll; + + Check(); +#endif // wxLONGLONG_TEST_MODE + return *this; } @@ -362,6 +405,12 @@ wxLongLongWx& wxLongLongWx::operator^=(const wxLongLongWx& ll) m_lo ^= ll.m_lo; m_hi ^= ll.m_hi; +#ifdef wxLONGLONG_TEST_MODE + m_ll ^= ll.m_ll; + + Check(); +#endif // wxLONGLONG_TEST_MODE + return *this; } @@ -374,38 +423,41 @@ wxLongLongWx wxLongLongWx::operator~() const wxLongLongWx wxLongLongWx::operator*(const wxLongLongWx& ll) const { - wxLongLongWx t(m_hi, m_lo); - wxLongLongWx q(ll.m_hi, ll.m_lo); - wxLongLongWx p; - int counter = 0; + wxLongLongWx res(*this); + res *= ll; - do - { - if ((q.m_lo & 1) != 0) - p += t; - q >>= 1; - t <<= 1; - counter++; - } - while ((counter < 64) && ((q.m_hi != 0) || (q.m_lo != 0))); - return p; + return res; } wxLongLongWx& wxLongLongWx::operator*=(const wxLongLongWx& ll) { wxLongLongWx t(m_hi, m_lo); wxLongLongWx q(ll.m_hi, ll.m_lo); - int counter = 0; + m_hi = m_lo = 0; + +#ifdef wxLONGLONG_TEST_MODE + wxLongLong_t llOld = m_ll; + m_ll = 0; +#endif // wxLONGLONG_TEST_MODE + + int counter = 0; do { if ((q.m_lo & 1) != 0) - *this += t; + *this += t; q >>= 1; t <<= 1; counter++; - } - while ((counter < 64) && ((q.m_hi != 0) || (q.m_lo != 0))); + } + while ((counter < 64) && ((q.m_hi != 0) || (q.m_lo != 0))); + +#ifdef wxLONGLONG_TEST_MODE + m_ll = llOld * ll.m_ll; + + Check(); +#endif // wxLONGLONG_TEST_MODE + return *this; } @@ -443,21 +495,6 @@ void wxLongLongWx::Divide(const wxLongLongWx& divisorIn, quotient = 0l; remainder = 0l; - // check for some particular cases - if ( divisor > dividend ) - { - remainder = dividend; - - return; - } - - if ( divisor == dividend ) - { - quotient = 1l; - - return; - } - // always do unsigned division and adjust the signs later: in C integer // division, the sign of the remainder is the same as the sign of the // dividend, while the sign of the quotient is the product of the signs of @@ -479,47 +516,59 @@ void wxLongLongWx::Divide(const wxLongLongWx& divisorIn, divisor = -divisor; } - // here: dividend > divisor and both are positibe: do unsigned division - size_t nBits = 64u; - wxLongLongWx d; - - #define IS_MSB_SET(ll) ((ll.m_hi) & (1 << (8*sizeof(long) - 1))) - - while ( remainder < divisor ) + // check for some particular cases + if ( divisor > dividend ) { - remainder <<= 1; - if ( IS_MSB_SET(dividend) ) - { - remainder |= 1; - } - - d = dividend; - dividend <<= 1; - - nBits--; + remainder = dividend; } - - // undo the last loop iteration - dividend = d; - remainder >>= 1; - nBits++; - - for ( size_t i = 0; i < nBits; i++ ) + else if ( divisor == dividend ) { - remainder <<= 1; - if ( IS_MSB_SET(dividend) ) + quotient = 1l; + } + else + { + // here: dividend > divisor and both are positibe: do unsigned division + size_t nBits = 64u; + wxLongLongWx d; + + #define IS_MSB_SET(ll) ((ll.m_hi) & (1 << (8*sizeof(long) - 1))) + + while ( remainder < divisor ) { - remainder |= 1; + remainder <<= 1; + if ( IS_MSB_SET(dividend) ) + { + remainder |= 1; + } + + d = dividend; + dividend <<= 1; + + nBits--; } - wxLongLongWx t = remainder - divisor; - dividend <<= 1; - quotient <<= 1; - if ( !IS_MSB_SET(t) ) - { - quotient |= 1; + // undo the last loop iteration + dividend = d; + remainder >>= 1; + nBits++; - remainder = t; + for ( size_t i = 0; i < nBits; i++ ) + { + remainder <<= 1; + if ( IS_MSB_SET(dividend) ) + { + remainder |= 1; + } + + wxLongLongWx t = remainder - divisor; + dividend <<= 1; + quotient <<= 1; + if ( !IS_MSB_SET(t) ) + { + quotient |= 1; + + remainder = t; + } } }