field *f = c->f;
mp *p, *q, *m, *s, *dx, *dy, *dz;
+ q = F_ADD(f, MP_NEW, a->y, a->z); /* %$y + z$% */
+ dz = F_SQR(f, MP_NEW, q); /* %$(y + z)^2 = y^2 + 2 y z + z^2$% */
p = F_SQR(f, MP_NEW, a->z); /* %$z^2$% */
- q = F_SQR(f, MP_NEW, p); /* %$z^4$% */
+ dz = F_SUB(f, dz, dz, p); /* %$y^2 + 2 y z$% */
+ q = F_SQR(f, q, p); /* %$z^4$% */
p = F_MUL(f, p, q, c->a); /* %$A z^4$% */
m = F_SQR(f, MP_NEW, a->x); /* %$x^2$% */
m = F_TPL(f, m, m); /* %$3 x^2$% */
m = F_ADD(f, m, m, p); /* %$m = 3 x^2 + A z^4$% */
- q = F_DBL(f, q, a->y); /* %$2 y$% */
- dz = F_MUL(f, MP_NEW, q, a->z); /* %$z' = 2 y z$% */
+ p = F_SQR(f, p, a->y); /* %$y^2$% */
+ dz = F_SUB(f, dz, dz, p); /* %$z' = 2 y z$% */
- p = F_SQR(f, p, q); /* %$4 y^2$% */
+ p = F_QDL(f, p, p); /* %$4 y^2$% */
s = F_MUL(f, MP_NEW, p, a->x); /* %$s = 4 x y^2$% */
q = F_SQR(f, q, p); /* %$16 y^4$% */
q = F_HLV(f, q, q); /* %$t = 8 y^4$% */
return (d);
}
+/* #define USE_SQUARE */
+
static ec *ecprojxdbl(ec_curve *c, ec *d, const ec *a)
{
if (EC_ATINF(a) || F_ZEROP(c->f, a->y))
field *f = c->f;
mp *p, *q, *m, *s, *dx, *dy, *dz;
+#ifdef USE_SQUARE
+ q = F_ADD(f, MP_NEW, a->y, a->z); /* %$y + z$% */
+ dz = F_SQR(f, MP_NEW, q); /* %$(y + z)^2 = y^2 + 2 y z + z^2$% */
+#else
+ q = MP_NEW;
+#endif
m = F_SQR(f, MP_NEW, a->z); /* %$z^2$% */
+#ifdef USE_SQUARE
+ dz = F_SUB(f, dz, dz, m); /* %$y^2 + 2 y z$% */
+#endif
p = F_SUB(f, MP_NEW, a->x, m); /* %$x - z^2$% */
- q = F_ADD(f, MP_NEW, a->x, m); /* %$x + z^2$% */
+ q = F_ADD(f, q, a->x, m); /* %$x + z^2$% */
m = F_MUL(f, m, p, q); /* %$x^2 - z^4$% */
m = F_TPL(f, m, m); /* %$m = 3 x^2 - 3 z^4$% */
- q = F_DBL(f, q, a->y); /* %$2 y$% */
- dz = F_MUL(f, MP_NEW, q, a->z); /* %$z' = 2 y z$% */
+#ifdef USE_SQUARE
+ p = F_SQR(f, p, a->y); /* %$y^2$% */
+ dz = F_SUB(f, dz, dz, p); /* %$z' = 2 y z$% */
+ p = F_QDL(f, p, p); /* %$4 y^2$% */
+#else
+ q = F_DBL(f, q, a->y); /* %$2 y% */
+ dz = F_MUL(f, MP_NEW, a->z, q); /* %$z' = 2 y z$% */
+ p = F_SQR(f, p, q); /* %$4 y^2% */
+#endif
- p = F_SQR(f, p, q); /* %$4 y^2$% */
s = F_MUL(f, MP_NEW, p, a->x); /* %$s = 4 x y^2$% */
q = F_SQR(f, q, p); /* %$16 y^4$% */
q = F_HLV(f, q, q); /* %$t = 8 y^4$% */