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Diffstat (limited to 'externals/g3dlite/G3D.lib/source/uint128.cpp')
-rw-r--r-- | externals/g3dlite/G3D.lib/source/uint128.cpp | 155 |
1 files changed, 0 insertions, 155 deletions
diff --git a/externals/g3dlite/G3D.lib/source/uint128.cpp b/externals/g3dlite/G3D.lib/source/uint128.cpp deleted file mode 100644 index 450009a5cff..00000000000 --- a/externals/g3dlite/G3D.lib/source/uint128.cpp +++ /dev/null @@ -1,155 +0,0 @@ -/** - @file uint128.cpp - - @maintainer Morgan McGuire, matrix@graphics3d.com - @author Kyle Whitson - - @created 2008-07-17 - @edited 2008-07-17 - */ - -#include "G3D/uint128.h" - -namespace G3D { - -/** Adds two 64-bit integers, placing the result and the overflow into 64-bit integers.*/ -static void addAndCarry(const uint64& _a, const uint64& _b, uint64& carry, uint64& result) { - - // Break each number into 4 32-bit chunks. Since we are using uints, right-shifting will fill with zeros. - // This eliminates the need to and with 0xFFFFFFFF. - uint32 a [2] = {_a & 0xFFFFFFFF, _a >> 32}; - uint32 b [2] = {_b & 0xFFFFFFFF, _b >> 32}; - - uint64 tmp = uint64(a[0]) + b[0]; - - result = tmp & 0xFFFFFFFF; - uint32 c = tmp >> 32; - - tmp = uint64(c) + a[1] + b[1]; - result += tmp << 32; - carry = (tmp >> 32); -} - -/** Multiplies two unsigned 64-bit integers, placing the result into one 64-bit int and the overflow into another.*/ -void multiplyAndCarry(const uint64& _a, const uint64& _b, uint64& carry, uint64& result) { - - // Break each number into 4 32-bit chunks. Since we are using uints, right-shifting will fill with zeros. - // This eliminates the need to and with 0xFFFFFFFF. - uint32 a [2] = {_a & 0xFFFFFFFF, _a >> 32}; - uint32 b [2] = {_b & 0xFFFFFFFF, _b >> 32}; - - uint64 prod [2][2]; - for(int i = 0; i < 2; ++i) { - for(int j = 0; j < 2; ++j) { - prod[i][j] = uint64(a[i]) * b[j]; - } - } - - // The product of the low bits of a and b will always fit into the result - result = prod[0][0]; - - // The product of the high bits of a and b will never fit into the result - carry = prod[1][1]; - - // The high 32 bits of prod[0][1] and prod[1][0] will never fit into the result - carry += prod[0][1] >> 32; - carry += prod[1][0] >> 32; - - uint64 tmp; - addAndCarry(result, (prod[0][1] << 32), tmp, result); - carry += tmp; - addAndCarry(result, (prod[1][0] << 32), tmp, result); - carry += tmp; -} - - -uint128::uint128(const uint64& hi, const uint64& lo) : hi(hi), lo(lo) { -} - -uint128::uint128(const uint64& lo) : hi(0), lo(lo) { -} - -uint128& uint128::operator+=(const uint128& x) { - - G3D::uint64 carry; - addAndCarry(lo, x.lo, carry, lo); - - // Adding the carry will change hi. Save the old hi bits in case this == x. - const uint64 xHi = x.hi; - hi += carry; - hi += xHi; - return *this; -} - -uint128& uint128::operator*=(const uint128& x) { - - // The low bits will get overwritten when doing the multiply, so back up both (in case &x == this) - const uint64 oldLo = lo; - const uint64 oldXLo = x.lo; - - G3D::uint64 carry; - multiplyAndCarry(oldLo, oldXLo, carry, lo); - - // Overflow doesn't matter here because the result is going into hi - any overflow will exceed the capacity of a 128-bit number - // Note: hi * x.hi will always overflow, since (x * 2^64) * (y * 2^64) = x*y*(2^128). The largest number expressable in 128 bits is - // 2^128 - 1. - hi = carry + (oldLo * x.hi) + (hi * oldXLo); - - return *this; -} - -uint128& uint128::operator^=(const uint128& x) { - hi ^= x.hi; - lo ^= x.lo; - return *this; -} - -uint128& uint128::operator&=(const uint128& x) { - hi &= x.hi; - lo &= x.lo; - return *this; -} - -uint128& uint128::operator|=(const uint128& x) { - hi |= x.hi; - lo |= x.lo; - return *this; -} - -bool uint128::operator==(const uint128& x) { - return (hi == x.hi) && (lo == x.lo); -} - -uint128& uint128::operator>>=(const int x) { - - //Before shifting, mask out the bits that will be shifted out of hi. - //Put a 1 in the first bit that will not be lost in the shift, then subtract 1 to get the mask. - uint64 mask = ((uint64)1L << x) - 1; - uint64 tmp = hi & mask; - hi >>= x; - - //Shift lo and add the bits shifted down from hi - lo = (lo >> x) + (tmp << (64 - x)); - - return *this; -} - -uint128& uint128::operator<<=(const int x) { - - //Before shifting, mask out the bits that will be shifted out of lo. - //Put a 1 in the last bit that will be lost in the shift, then subtract 1 to get the logical inverse of the mask. - //A bitwise NOT will then produce the correct mask. - uint64 mask = ~((((uint64)1L) << (64 - x)) - 1); - uint64 tmp = lo & mask; - lo <<= x; - - //Shift hi and add the bits shifted up from lo - hi = (hi << x) + (tmp >> (64 - x)); - - return *this; -} - -uint128 uint128::operator&(const uint128& x) { - return uint128(hi & x.hi, lo & x.lo); -} -} |