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try new gcd

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Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>
This commit is contained in:
Nikolaj Bjorner 2018-06-06 17:42:44 -07:00
parent add8d26807
commit 8ab428b660
1 changed files with 87 additions and 33 deletions
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120
src/util/mpz.cpp
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@ -45,43 +45,97 @@ Revision History:
#define LEHMER_GCD
#endif
template<typename T>
static T gcd_core(T u, T v) {
if (u == 0)
return v;
if (v == 0)
return u;
int k;
for (k = 0; ((u | v) & 1) == 0; ++k) {
u >>= 1;
v >>= 1;
}
while ((u & 1) == 0)
u >>= 1;
#if 1
#include <immintrin.h>
#define _trailing_zeros32(x) _tzcnt_u32(x)
#ifdef _AMD64_
#define _trailing_zeros64(x) _tzcnt_u64(x)
#else
inline uint64 _trailing_zeros64(uint64 x) {
uint64 r = 0;
for (; 0 == (x & 1) && r < 64; ++r, x >>= 1);
return r;
}
#endif
#else
inline unsigned _trailing_zeros32(unsigned x) {
unsigned r = 0;
for (; 0 == (x & 1) && r < 32; ++r, x >>= 1);
return r;
}
#endif
#define _bit_min(x, y) (y + ((x - y) & ((int)(x - y) >> 31)))
#define _bit_max(x, y) (x - ((x - y) & ((int)(x - y) >> 31)))
unsigned u_gcd(unsigned u, unsigned v) {
if (u == 0) return v;
if (v == 0) return u;
unsigned shift = _trailing_zeros32(u | v);
u >>= _trailing_zeros32(u);
v >>= _trailing_zeros32(v);
if (u == 1 || v == 1) return 1 << shift;
if (u == v) return u << shift;
do {
while ((v & 1) == 0)
v >>= 1;
if (u < v) {
v -= u;
}
else {
T diff = u - v;
u = v;
v = diff;
}
v >>= 1;
} while (v != 0);
return u << k;
#if 1
unsigned diff = u - v;
unsigned mdiff = diff & (unsigned)((int)diff >> 31);
u = v + mdiff; // min
v = diff - 2 * mdiff; // if v <= u: u - v, if v > u: v - u = u - v - 2 * (u - v)
#endif
#if 0
unsigned t = _bit_max(u, v);
u = _bit_min(u, v);
v = t;
v -= u;
#endif
#if 0
unsigned t = std::max(u, v);
u = std::min(u,v);
v = t;
v -= u;
#endif
#if 0
if (u > v) std::swap(u, v);
v -= u;
#endif
#if 0
unsigned d1 = u - v;
unsigned d2 = v - u;
unsigned md21 = d2 & (unsigned)((int)d1 >> 31);
unsigned md12 = d1 & (unsigned)((int)d2 >> 31);
u = _bit_min(u, v);
v = md12 | md21;
#endif
v >>= _trailing_zeros32(v);
}
while (v != 0);
return u << shift;
}
uint64 u64_gcd(uint64 u, uint64 v) {
if (u == 0) return v;
if (v == 0) return u;
if (u == 1 || v == 1) return 1;
uint64 shift = _trailing_zeros64(u | v);
u >>= _trailing_zeros64(u);
do {
v >>= _trailing_zeros64(v);
if (u > v) std::swap(u, v);
v -= u;
}
while (v != 0);
return u << shift;
}
unsigned u_gcd(unsigned u, unsigned v) { return gcd_core(u, v); }
uint64_t u64_gcd(uint64_t u, uint64_t v) { return gcd_core(u, v); }
template<bool SYNCH>
mpz_manager<SYNCH>::mpz_manager():