path: root/src/cube_avx2.h

typedef __m256i cube_t;

#define _co2_avx2 _mm256_set_epi64x(0, 0, 0, INT64_C(0x6060606060606060))
#define _cocw_avx2 _mm256_set_epi64x(0, 0, 0, INT64_C(0x2020202020202020))
#define _cp_avx2 _mm256_set_epi64x(0, 0, 0, INT64_C(0x0707070707070707))
#define _ep_avx2 \
    _mm256_set_epi64x(INT64_C(0x0F0F0F0F), INT64_C(0x0F0F0F0F0F0F0F0F), 0, 0)
#define _eo_avx2 \
    _mm256_set_epi64x(INT64_C(0x10101010), INT64_C(0x1010101010101010), 0, 0)

#define static_cube(c_ufr, c_ubl, c_dfl, c_dbr, c_ufl, c_ubr, c_dfr, c_dbl, \
    e_uf, e_ub, e_db, e_df, e_ur, e_ul, e_dl, e_dr, e_fr, e_fl, e_bl, e_br) \
    _mm256_set_epi8(0, 0, 0, 0, e_br, e_bl, e_fl, e_fr, \
        e_dr, e_dl, e_ul, e_ur, e_df, e_db, e_ub, e_uf, \
        0, 0, 0, 0, 0, 0, 0, 0, \
        c_dbl, c_dfr, c_ubr, c_ufl, c_dbr, c_dfl, c_ubl, c_ufr)
#define zero _mm256_set_epi64x(0, 0, 0, 0)
#define solved static_cube( \
    0, 1, 2, 3, 4, 5, 6, 7, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11)

_static void pieces(cube_t *, uint8_t [static 8], uint8_t [static 12]);
_static_inline bool equal(cube_t, cube_t);
_static_inline cube_t invertco(cube_t);
_static_inline cube_t compose_epcpeo(cube_t, cube_t);
_static_inline cube_t compose_edges(cube_t, cube_t);
_static_inline cube_t compose_corners(cube_t, cube_t);
_static_inline cube_t compose(cube_t, cube_t);
_static_inline cube_t inverse(cube_t);

_static_inline int64_t coord_co(cube_t);
_static_inline int64_t coord_csep(cube_t);
_static_inline int64_t coord_cocsep(cube_t);
_static_inline int64_t coord_eo(cube_t);
_static_inline int64_t coord_esep(cube_t);

_static_inline void copy_corners(cube_t *, cube_t);
_static_inline void copy_edges(cube_t *, cube_t);
_static_inline void set_eo(cube_t *, int64_t);
_static_inline cube_t invcoord_esep(int64_t);

_static void
pieces(cube_t *cube, uint8_t c[static 8], uint8_t e[static 12])
{
	uint8_t aux[32];

	_mm256_storeu_si256((__m256i_u *)aux, *cube);
	memcpy(c, aux, 8);
	memcpy(e, aux+16, 12);
}

_static_inline bool
equal(cube_t c1, cube_t c2)
{
	int32_t mask;
	__m256i cmp;

	cmp = _mm256_cmpeq_epi8(c1, c2);
	mask = _mm256_movemask_epi8(cmp);

	return mask == ~0;
}

_static_inline cube_t
invertco(cube_t c)
{
        cube_t co, shleft, shright, summed, newco, cleanco, ret;

        co = _mm256_and_si256(c, _co2_avx2);
        shleft = _mm256_slli_epi32(co, 1);
        shright = _mm256_srli_epi32(co, 1);
        summed = _mm256_or_si256(shleft, shright);
        newco = _mm256_and_si256(summed, _co2_avx2);
        cleanco = _mm256_xor_si256(c, co);
        ret = _mm256_or_si256(cleanco, newco);

        return ret;
}

_static_inline cube_t
compose_epcpeo(cube_t c1, cube_t c2)
{
	cube_t b, s, eo2;

	/* Permute and clean unused bits */
	s = _mm256_shuffle_epi8(c1, c2);
	b = _mm256_set_epi8(
		~0, ~0, ~0, ~0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
		~0, ~0, ~0, ~0, ~0, ~0, ~0, ~0, 0, 0, 0, 0, 0, 0, 0, 0
	);
	s = _mm256_andnot_si256(b, s);

	/* Change EO */
	eo2 = _mm256_and_si256(c2, _eo_avx2);
	s = _mm256_xor_si256(s, eo2);

	return s;
}

_static_inline cube_t
compose_edges(cube_t c1, cube_t c2)
{
	return compose_epcpeo(c1, c2);
}

_static_inline cube_t
compose_corners(cube_t c1, cube_t c2)
{
	/*
	 * We do a full compose. Minor optimizations are possible, like
	 * saving one instruction by not doing EO, but it should not
	 * be significant.
	 */
	return compose(c1, c2);
}

_static_inline cube_t
compose(cube_t c1, cube_t c2)
{
	cube_t s, co1, co2, aux, auy1, auy2, auz1, auz2;

	s = compose_epcpeo(c1, c2);

	/* Change CO */
	co1 = _mm256_and_si256(s, _co2_avx2);
	co2 = _mm256_and_si256(c2, _co2_avx2);
	aux = _mm256_add_epi8(co1, co2);
	auy1 = _mm256_add_epi8(aux, _cocw_avx2);
	auy2 = _mm256_srli_epi32(auy1, 2);
	auz1 = _mm256_add_epi8(aux, auy2);
	auz2 = _mm256_and_si256(auz1, _co2_avx2);

	/* Put together */
	s = _mm256_andnot_si256(_co2_avx2, s);
	s = _mm256_or_si256(s, auz2);

	return s;
}

_static_inline cube_t
cleanaftershuffle(cube_t c)
{
	__m256i b;

	b = _mm256_set_epi8(
		~0, ~0, ~0, ~0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
		~0, ~0, ~0, ~0, ~0, ~0, ~0, ~0, 0, 0, 0, 0, 0, 0, 0, 0
	);

	return _mm256_andnot_si256(b, c);
}

_static_inline cube_t
inverse(cube_t c)
{
	/* Method taken from Andrew Skalski's vcube[1]. The addition sequence
	 * was generated using [2].
	 * [1] https://github.com/Voltara/vcube
	 * [2] http://wwwhomes.uni-bielefeld.de/achim/addition_chain.html
	 */
	cube_t v3, vi, vo, vp, ret;

	v3 = _mm256_shuffle_epi8(c, c);
	v3 = _mm256_shuffle_epi8(v3, c);
	vi = _mm256_shuffle_epi8(v3, v3);
	vi = _mm256_shuffle_epi8(vi, vi);
	vi = _mm256_shuffle_epi8(vi, vi);
	vi = _mm256_shuffle_epi8(vi, v3);
	vi = _mm256_shuffle_epi8(vi, vi);
	vi = _mm256_shuffle_epi8(vi, vi);
	vi = _mm256_shuffle_epi8(vi, vi);
	vi = _mm256_shuffle_epi8(vi, vi);
	vi = _mm256_shuffle_epi8(vi, c);
	vi = _mm256_shuffle_epi8(vi, vi);
	vi = _mm256_shuffle_epi8(vi, vi);
	vi = _mm256_shuffle_epi8(vi, vi);
	vi = _mm256_shuffle_epi8(vi, vi);
	vi = _mm256_shuffle_epi8(vi, vi);
	vi = _mm256_shuffle_epi8(vi, v3);
	vi = _mm256_shuffle_epi8(vi, vi);
	vi = _mm256_shuffle_epi8(vi, c);

	vo = _mm256_and_si256(c, _mm256_or_si256(_eo_avx2, _co2_avx2));
	vo = _mm256_shuffle_epi8(vo, vi);
	vp = _mm256_andnot_si256(_mm256_or_si256(_eo_avx2, _co2_avx2), vi);
	ret = _mm256_or_si256(vp, vo);
	ret = cleanaftershuffle(ret);
	
	return invertco(ret);
}

_static_inline int64_t
coord_co(cube_t c)
{
	cube_t co;
	int64_t mem[4], ret, i, p;

	co = _mm256_and_si256(c, _co2_avx2);
	_mm256_storeu_si256((__m256i *)mem, co);

	mem[0] >>= 5;
	for (i = 0, ret = 0, p = 1; i < 7; i++, mem[0] >>= 8, p *= 3)
		ret += (mem[0] & 3) * p;

	return ret;
}

_static_inline int64_t
coord_csep(cube_t c)
{
	cube_t cp, shifted;
	int64_t mask;

	cp = _mm256_and_si256(c, _cp_avx2);
	shifted = _mm256_slli_epi32(cp, 5);
	mask = _mm256_movemask_epi8(shifted);

	return mask & 0x7F;
}

_static_inline int64_t
coord_cocsep(cube_t c)
{
	return (coord_co(c) << 7) + coord_csep(c);
}

_static_inline int64_t
coord_eo(cube_t c)
{
	cube_t eo, shifted;
	int64_t mask;

	eo = _mm256_and_si256(c, _eo_avx2);
	shifted = _mm256_slli_epi32(eo, 3);
	mask = _mm256_movemask_epi8(shifted);

	return mask >> 17;
}

_static_inline int64_t
coord_esep(cube_t c)
{
	cube_t ep;
	int64_t e, mem[4], i, j, jj, k, l, ret1, ret2, bit1, bit2, is1;

	ep = _mm256_and_si256(c, _ep_avx2);
	_mm256_storeu_si256((__m256i *)mem, ep);

	mem[3] <<= 8;
	ret1 = ret2 = 0;
	k = l = 4;
	for (i = 0, j = 0; i < 12; i++, mem[i/8 + 2] >>= 8) {
		e = mem[i/8 + 2];

		bit1 = (e & _esepbit1) >> 2;
		bit2 = (e & _esepbit2) >> 3;
		is1 = (1 - bit2) * bit1;

		ret1 += bit2 * binomial[11-i][k];
		k -= bit2;

		jj = j < 8;
		ret2 += jj * is1 * binomial[7-(j*jj)][l];
		l -= is1;
		j += (1-bit2);
	}

	return ret1 * 70 + ret2;
}

_static_inline void
copy_corners(cube_t *dest, cube_t src)
{
	*dest = _mm256_blend_epi32(*dest, src, 0x0F);
}

_static_inline void
copy_edges(cube_t *dest, cube_t src)
{
	*dest = _mm256_blend_epi32(*dest, src, 0xF0);
}

_static_inline void
set_eo(cube_t *cube, int64_t eo)
{
	int64_t eo12, eotop, eobot;
	__m256i veo;

	eo12 = (eo << 1) + (_mm_popcnt_u64(eo) % 2);
	eotop = (eo12 & (1 << 11)) << 17 |
		(eo12 & (1 << 10)) << 10 |
		(eo12 & (1 << 9)) << 3 |
		(eo12 & (1 << 8)) >> 4;
	eobot = (eo12 & (1 << 7)) << 53 |
		(eo12 & (1 << 6)) << 46 |
		(eo12 & (1 << 5)) << 39 |
		(eo12 & (1 << 4)) << 32 |
		(eo12 & (1 << 3)) << 25 |
		(eo12 & (1 << 2)) << 18 |
		(eo12 & (1 << 1)) << 11 |
		(eo12 & 1) << 4;
	veo = _mm256_set_epi64x(eotop, eobot, 0, 0);

	*cube = _mm256_andnot_si256(_eo_avx2, *cube);
	*cube = _mm256_or_si256(*cube, veo);
}

_static_inline cube_t
invcoord_esep(int64_t esep)
{
	cube_t eee, ret;
	int64_t bit1, bit2, i, j, jj, k, l, s, v, w, is1, set1, set2;
	uint8_t mem[32];
	uint8_t slice[3] = {0};

	set1 = esep % 70;
	set2 = esep / 70;

	for (i = 0, j = 0, k = 4, l = 4; i < 12; i++) {
		v = binomial[11-i][k];
		jj = j < 8;
		w = jj * binomial[7-(j*jj)][l];
		bit2 = set2 >= v;
		bit1 = set1 >= w;
		is1 = (1 - bit2) * bit1;

		set2 -= bit2 * v;
		k -= bit2;
		set1 -= is1 * w;
		l -= is1;
		j += (1-bit2);
		s = 2*bit2 + (1-bit2)*bit1;

		mem[i+16] = (slice[s]++) | (uint8_t)(s << 2);
	}

	ret = solved;
	eee = _mm256_loadu_si256((__m256i_u *)&mem);
	copy_edges(&ret, eee);

	return ret;
}