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split function for BLS12-381 to ec::local
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@herumi
herumi committed Apr 26, 2024
1 parent 1e2e12f commit 2740a2b
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Showing 3 changed files with 39 additions and 52 deletions.
31 changes: 5 additions & 26 deletions include/mcl/bn.hpp
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Original file line number Diff line number Diff line change
Expand Up @@ -726,34 +726,13 @@ struct GLV1 : mcl::GLV1T<G1, Fr> {
}
static inline void optimizedSplitForBLS12_381(mpz_class u[2], const mpz_class& x)
{
assert(sizeof(Unit) == 8);
/*
z = -0xd201000000010000
L = z^2-1 = 0xac45a4010001a40200000000ffffffff
r = L^2+L+1 = 0x73eda753299d7d483339d80809a1d80553bda402fffe5bfeffffffff00000001
s=255
v = 0xbe35f678f00fd56eb1fb72917b67f718
*/
mpz_class& a = u[0];
mpz_class& b = u[1];
static const uint64_t Lv[] = { 0x00000000ffffffff, 0xac45a4010001a402 };
static const uint64_t vv[] = { 0xb1fb72917b67f718, 0xbe35f678f00fd56e };
static const size_t n = 128 / mcl::UnitBitSize;
Unit t[n*3];
// n = 128 bit
// t[n*3] = x[n*2] * vv[n]
mcl::bint::mulNM(t, gmp::getUnit(x), n*2, (const Unit*)vv, n);
// t[n] <- t[n*3]
mcl::bint::shrT<n+1>(t, t+n*2-1, mcl::UnitBitSize-1); // >>255
Unit xa[n*2], a[2], b[2];
mcl::gmp::getArray(xa, n*2, x);
ec::local::optimizedSplitRawForBLS12_381(a, b, xa);
bool dummy;
gmp::setArray(&dummy, b, t, n);
Unit t2[n*2];
// t2[n*2] = t[n] * Lv[n]
// Do not overlap I/O buffers on pre-Broadwell CPUs.
mcl::bint::mulT<n>(t2, t, (const Unit*)Lv);
// t[n] = x[n*2] - t2[n*2]
mcl::bint::subT<n>(t, gmp::getUnit(x), t2);
gmp::setArray(&dummy, a, t, n);
gmp::setArray(&dummy, u[0], a, n);
gmp::setArray(&dummy, u[1], b, n);
(void)dummy;
}
};
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29 changes: 29 additions & 0 deletions include/mcl/ec.hpp
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Original file line number Diff line number Diff line change
Expand Up @@ -242,6 +242,35 @@ void normalizeVecT(Eout& Q, Ein& P, size_t n, size_t N = 256)
}
}

inline void optimizedSplitRawForBLS12_381(Unit a[2], Unit b[2], const Unit x[4])
{
assert(sizeof(Unit) == 8);
/*
z = -0xd201000000010000
L = z^2-1 = 0xac45a4010001a40200000000ffffffff
r = L^2+L+1 = 0x73eda753299d7d483339d80809a1d80553bda402fffe5bfeffffffff00000001
s=255
v = 0xbe35f678f00fd56eb1fb72917b67f718
*/
static const uint64_t Lv[] = { 0x00000000ffffffff, 0xac45a4010001a402 };
static const uint64_t vv[] = { 0xb1fb72917b67f718, 0xbe35f678f00fd56e };
static const size_t n = 128 / mcl::UnitBitSize;
Unit t[n*3];
// n = 128 bit
// t[n*3] = x[n*2] * vv[n]
mcl::bint::mulNM(t, x, n*2, vv, n);
// b[n] = t[n*3]>>255
mcl::bint::shrT<n+1>(t, t+n*2-1, mcl::UnitBitSize-1); // >>255
b[0] = t[0];
b[1] = t[1];
Unit t2[n*2];
// t2[n*2] = t[n] * Lv[n]
// Do not overlap I/O buffers on pre-Broadwell CPUs.
mcl::bint::mulT<n>(t2, t, Lv);
// a[n] = x[n*2] - t2[n*2]
mcl::bint::subT<n>(a, x, t2);
}

} // mcl::ec::local

// [X:Y:Z] as Proj = (X/Z, Y/Z) as Affine = [XZ:YZ^2:Z] as Jacobi
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31 changes: 5 additions & 26 deletions src/msm_avx.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -471,27 +471,6 @@ inline Vec getUnitAt(const Vec *x, size_t xN, size_t bitPos)
return vor(vpsrlq(x[q], r), vpsllq(x[q+1], bitSize - r));
}

inline void split(Unit a[2], Unit b[2], const Unit x[4])
{
/*
z = -0xd201000000010000
L = z^2-1 = 0xac45a4010001a40200000000ffffffff
r = L^2+L+1 = 0x73eda753299d7d483339d80809a1d80553bda402fffe5bfeffffffff00000001
s=255
v = 0xbe35f678f00fd56eb1fb72917b67f718
*/
static const uint64_t Lv[] = { 0x00000000ffffffff, 0xac45a4010001a402 };
static const uint64_t vv[] = { 0xb1fb72917b67f718, 0xbe35f678f00fd56e };
static const size_t n = 128 / mcl::UnitBitSize;
Unit t[n*3];
mcl::bint::mulNM(t, x, n*2, vv, n);
mcl::bint::shrT<n+1>(t, t+n*2-1, mcl::UnitBitSize-1); // >>255
b[0] = t[0];
b[1] = t[1];
mcl::bint::mulT<n>(t, t, Lv);
mcl::bint::subT<n>(a, x, t);
}

class Montgomery {
Unit v_[N];
public:
Expand Down Expand Up @@ -1120,7 +1099,7 @@ struct EcM {
static void mulGLV(EcM& Q, const EcM& _P, const Vec y[4])
{
EcM P = _P;
if (!isProj) mcl::ec::ProjToJacobi(P, _P);
// if (!isProj) mcl::ec::ProjToJacobi(P, _P);
Vec a[2], b[2];
EcM tbl1[tblN], tbl2[tblN];
makeTable<isProj, mixed>(tbl1, P);
Expand All @@ -1134,7 +1113,7 @@ struct EcM {
for (size_t i = 0; i < M; i++) {
Unit buf[4] = { src[i+M*0], src[i+M*1], src[i+M*2], src[i+M*3] };
Unit aa[2], bb[2];
split(aa, bb, buf);
mcl::ec::local::optimizedSplitRawForBLS12_381(aa, bb, buf);
pa[i+M*0] = aa[0]; pa[i+M*1] = aa[1];
pb[i+M*0] = bb[0]; pb[i+M*1] = bb[1];
}
Expand Down Expand Up @@ -1167,7 +1146,7 @@ struct EcM {
mul(T, T, b, 2);
add(Q, Q, T);
#endif
if (!isProj) mcl::ec::JacobiToProj(Q, Q);
// if (!isProj) mcl::ec::JacobiToProj(Q, Q);
}
static void mulGLVbn(mcl::msm::G1A _Q[8], mcl::msm::G1A _P[8], const Vec y[4])
{
Expand Down Expand Up @@ -1356,7 +1335,7 @@ void mulVecAVX512(Unit *_P, Unit *_x, const Unit *_y, size_t n)
Unit ya[4];
fr->fromMont(ya, y[i*8+j].v);
Unit a[2], b[2];
split(a, b, ya);
mcl::ec::local::optimizedSplitRawForBLS12_381(a, b, ya);
py[j+0] = a[0];
py[j+8] = a[1];
py[j+16] = b[0];
Expand Down Expand Up @@ -1393,7 +1372,7 @@ void mulEachAVX512(Unit *_x, const Unit *_y, size_t n)
const bool mixed = true;
mcl::msm::G1A *x = (mcl::msm::G1A*)_x;
const mcl::msm::FrA *y = (const mcl::msm::FrA*)_y;
g_param.normalizeVecG1(x, x, n);
if (!isProj) g_param.normalizeVecG1(x, x, n);
for (size_t i = 0; i < n; i += 8) {
EcM P;
Vec yv[4];
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