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Internal mul256 implementation

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This commit is contained in:
Paweł Bylica 2015-01-19 13:53:31 +01:00
parent 003ba383c3
commit de186f1ed1
1 changed files with 52 additions and 4 deletions
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56
libevmjit/Arith256.cpp
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@ -118,6 +118,56 @@ namespace
else
return (u256)(c_end + _u);
}
using uint128 = __uint128_t;
// uint128 add(uint128 a, uint128 b) { return a + b; }
// uint128 mul(uint128 a, uint128 b) { return a * b; }
//
// uint128 mulq(uint64_t x, uint64_t y)
// {
// return (uint128)x * (uint128)y;
// }
//
// uint128 addc(uint64_t x, uint64_t y)
// {
// return (uint128)x * (uint128)y;
// }
struct uint256
{
uint64_t lo;
uint64_t mid;
uint128 hi;
};
// uint256 add(uint256 x, uint256 y)
// {
// auto lo = (uint128) x.lo + y.lo;
// auto mid = (uint128) x.mid + y.mid + (lo >> 64);
// return {lo, mid, x.hi + y.hi + (mid >> 64)};
// }
uint256 mul(uint256 x, uint256 y)
{
auto t1 = (uint128) x.lo * y.lo;
auto t2 = (uint128) x.lo * y.mid;
auto t3 = x.lo * y.hi;
auto t4 = (uint128) x.mid * y.lo;
auto t5 = (uint128) x.mid * y.mid;
auto t6 = x.mid * y.hi;
auto t7 = x.hi * y.lo;
auto t8 = x.hi * y.mid;
auto lo = (uint64_t) t1;
auto m1 = (t1 >> 64) + (uint64_t) t2;
auto m2 = (uint64_t) m1;
auto mid = (uint128) m2 + (uint64_t) t4;
auto hi = (t2 >> 64) + t3 + (t4 >> 64) + t5 + (t6 << 64) + t7
+ (t8 << 64) + (m1 >> 64) + (mid >> 64);
return {lo, (uint64_t)mid, hi};
}
}
}
@ -130,11 +180,9 @@ extern "C"
using namespace dev::eth::jit;
EXPORT void arith_mul(i256* _arg1, i256* _arg2, i256* o_result)
EXPORT void arith_mul(uint256* _arg1, uint256* _arg2, uint256* o_result)
{
auto arg1 = llvm2eth(*_arg1);
auto arg2 = llvm2eth(*_arg2);
*o_result = eth2llvm(arg1 * arg2);
*o_result = mul(*_arg1, *_arg2);
}
EXPORT void arith_div(i256* _arg1, i256* _arg2, i256* o_result)