static void select(out GroupElementPreComp t, int pos, sbyte b) { GroupElementPreComp minust; byte bnegative = negative(b); byte babs = (byte)(b - (((-bnegative) & b) << 1)); ge_precomp_0(out t); var table = LookupTables.Base[pos]; cmov(ref t, ref table[0], equal(babs, 1)); cmov(ref t, ref table[1], equal(babs, 2)); cmov(ref t, ref table[2], equal(babs, 3)); cmov(ref t, ref table[3], equal(babs, 4)); cmov(ref t, ref table[4], equal(babs, 5)); cmov(ref t, ref table[5], equal(babs, 6)); cmov(ref t, ref table[6], equal(babs, 7)); cmov(ref t, ref table[7], equal(babs, 8)); minust.yplusx = t.yminusx; minust.yminusx = t.yplusx; FieldOperations.fe_neg(out minust.xy2d, ref t.xy2d); cmov(ref t, ref minust, bnegative); }
/* * r = p - q */ internal static void ge_msub(out GroupElementP1P1 r, ref GroupElementP3 p, ref GroupElementPreComp q) { FieldElement t0; /* qhasm: enter ge_msub */ /* qhasm: fe X1 */ /* qhasm: fe Y1 */ /* qhasm: fe Z1 */ /* qhasm: fe T1 */ /* qhasm: fe ypx2 */ /* qhasm: fe ymx2 */ /* qhasm: fe xy2d2 */ /* qhasm: fe X3 */ /* qhasm: fe Y3 */ /* qhasm: fe Z3 */ /* qhasm: fe T3 */ /* qhasm: fe YpX1 */ /* qhasm: fe YmX1 */ /* qhasm: fe A */ /* qhasm: fe B */ /* qhasm: fe C */ /* qhasm: fe D */ /* qhasm: YpX1 = Y1+X1 */ /* asm 1: fe_add(>YpX1=fe#1,<Y1=fe#12,<X1=fe#11); */ /* asm 2: fe_add(>YpX1=r.X,<Y1=p.Y,<X1=p.X); */ FieldOperations.fe_add(out r.X, ref p.Y, ref p.X); /* qhasm: YmX1 = Y1-X1 */ /* asm 1: fe_sub(>YmX1=fe#2,<Y1=fe#12,<X1=fe#11); */ /* asm 2: fe_sub(>YmX1=r.Y,<Y1=p.Y,<X1=p.X); */ FieldOperations.fe_sub(out r.Y, ref p.Y, ref p.X); /* qhasm: A = YpX1*ymx2 */ /* asm 1: fe_mul(>A=fe#3,<YpX1=fe#1,<ymx2=fe#16); */ /* asm 2: fe_mul(>A=r.Z,<YpX1=r.X,<ymx2=q.yminusx); */ FieldOperations.fe_mul(out r.Z, ref r.X, ref q.yminusx); /* qhasm: B = YmX1*ypx2 */ /* asm 1: fe_mul(>B=fe#2,<YmX1=fe#2,<ypx2=fe#15); */ /* asm 2: fe_mul(>B=r.Y,<YmX1=r.Y,<ypx2=q.yplusx); */ FieldOperations.fe_mul(out r.Y, ref r.Y, ref q.yplusx); /* qhasm: C = xy2d2*T1 */ /* asm 1: fe_mul(>C=fe#4,<xy2d2=fe#17,<T1=fe#14); */ /* asm 2: fe_mul(>C=r.T,<xy2d2=q.xy2d,<T1=p.T); */ FieldOperations.fe_mul(out r.T, ref q.xy2d, ref p.T); /* qhasm: D = 2*Z1 */ /* asm 1: fe_add(>D=fe#5,<Z1=fe#13,<Z1=fe#13); */ /* asm 2: fe_add(>D=t0,<Z1=p.Z,<Z1=p.Z); */ FieldOperations.fe_add(out t0, ref p.Z, ref p.Z); /* qhasm: X3 = A-B */ /* asm 1: fe_sub(>X3=fe#1,<A=fe#3,<B=fe#2); */ /* asm 2: fe_sub(>X3=r.X,<A=r.Z,<B=r.Y); */ FieldOperations.fe_sub(out r.X, ref r.Z, ref r.Y); /* qhasm: Y3 = A+B */ /* asm 1: fe_add(>Y3=fe#2,<A=fe#3,<B=fe#2); */ /* asm 2: fe_add(>Y3=r.Y,<A=r.Z,<B=r.Y); */ FieldOperations.fe_add(out r.Y, ref r.Z, ref r.Y); /* qhasm: Z3 = D-C */ /* asm 1: fe_sub(>Z3=fe#3,<D=fe#5,<C=fe#4); */ /* asm 2: fe_sub(>Z3=r.Z,<D=t0,<C=r.T); */ FieldOperations.fe_sub(out r.Z, ref t0, ref r.T); /* qhasm: T3 = D+C */ /* asm 1: fe_add(>T3=fe#4,<D=fe#5,<C=fe#4); */ /* asm 2: fe_add(>T3=r.T,<D=t0,<C=r.T); */ FieldOperations.fe_add(out r.T, ref t0, ref r.T); /* qhasm: return */ }
internal static void ge_precomp_0(out GroupElementPreComp h) { FieldOperations.fe_1(out h.yplusx); FieldOperations.fe_1(out h.yminusx); FieldOperations.fe_0(out h.xy2d); }
static void cmov(ref GroupElementPreComp t, ref GroupElementPreComp u, byte b) { FieldOperations.fe_cmov(ref t.yplusx, ref u.yplusx, b); FieldOperations.fe_cmov(ref t.yminusx, ref u.yminusx, b); FieldOperations.fe_cmov(ref t.xy2d, ref u.xy2d, b); }