/*------------------------------------------------------------------*/
static void poly_xpow(poly_t res, u_int32_t shift, u_int32_t n,
poly_t mod, u_int32_t p) {
/* Modular exponentiation of polynomials with
finite-field coefficients, i.e. res = (x-shift) ^ n % mod
with all polynomial coefficients reduced modulo p.
n is assumed nonzero */
poly_t modnorm;
u_int32_t msw;
u_int32_t i, d;
u_int32_t buf[2*NUM_POLY_COEFFS] = {0};
u_int64_t psq;
poly_make_monic(modnorm, mod, p);
d = modnorm->degree;
OP1(0) = shift;
OP1(1) = 1;
for (i = 0; i <= d; i++)
MOD(i) = modnorm->coef[i];
msw = 0x80000000;
while (!(n & msw)) {
msw >>= 1;
}
msw >>= 1;
psq = (u_int64_t)p * (u_int64_t)p;
/* use left-to-right binary exponentiation, not
the right-to-left variety. For factor base generation
the base always has degree less than modnorm, and the
left-to-right method preserves that, saving time during
modular multiplication */
while (msw) {
poly_expo_square(buf, d, p, psq);
if (n & msw) {
poly_expo_modmul(buf, d, shift, p, psq);
}
msw >>= 1;
}
res->degree = d;
for (i = 0; i <= d; i++)
res->coef[i] = OP1(i);
poly_fix_degree(res);
}
int read_opcode(void)
{
uint16_t inst;
if (cpu.PC == MEM_SIZE)
return EOF;
if (cpu.PC == rom_size)
return END_ROM;
inst = (mem[cpu.PC]<<8) | mem[cpu.PC+1];
op1 = OP1(inst);
op2 = OP2(inst);
op3 = OP3(inst);
op4 = OP4(inst);
cpu.PC += 2;
return cpu.PC;
}
/*------------------------------------------------------------------*/
static void poly_expo_square(u_int32_t *buf, u_int32_t dm, u_int32_t p, u_int64_t psq)
{
/* OP1 = OP1 * OP1 mod MOD
OP1 and MOD are both of degree dm */
u_int32_t i;
u_int32_t q;
u_int64_t acc[NUM_POLY_COEFFS];
for (i = 0; i < dm; i++)
acc[i] = (u_int64_t) (OP1(i)) * (u_int64_t)(OP1(dm-1));
for (i = dm - 2; (int32_t)i >= 0; i--) {
q = mp_mod64(acc[dm-1], p);
switch(dm-1) {
case 7: acc[7] = sqr_mac(OP1(7), OP1(i), acc[6],
q, MOD(7), psq);
case 6: acc[6] = sqr_mac(OP1(6), OP1(i), acc[5],
q, MOD(6), psq);
case 5: acc[5] = sqr_mac(OP1(5), OP1(i), acc[4],
q, MOD(5), psq);
case 4: acc[4] = sqr_mac(OP1(4), OP1(i), acc[3],
q, MOD(4), psq);
case 3: acc[3] = sqr_mac(OP1(3), OP1(i), acc[2],
q, MOD(3), psq);
case 2: acc[2] = sqr_mac(OP1(2), OP1(i), acc[1],
q, MOD(2), psq);
case 1: acc[1] = sqr_mac(OP1(1), OP1(i), acc[0],
q, MOD(1), psq);
case 0: acc[0] = sqr_mac0(OP1(0), OP1(i), q, MOD(0), psq);
break;
}
}
for (i = 0; i < dm; i++)
OP1(i) = mp_mod64(acc[i], p);
}
/*------------------------------------------------------------------*/
static void poly_expo_modmul(u_int32_t *buf, u_int32_t dm, u_int32_t shift, u_int32_t p, u_int64_t psq)
{
/* OP1 = OP1 * (x - shift) mod MOD
OP1 and MOD are of degree dm */
u_int32_t q;
u_int32_t zero = 0;
q = OP1(dm-1);
switch(dm-1) {
case 7: OP1(7) = mul_mac(OP1(7), shift, OP1(6), q, MOD(7), p, psq);
case 6: OP1(6) = mul_mac(OP1(6), shift, OP1(5), q, MOD(6), p, psq);
case 5: OP1(5) = mul_mac(OP1(5), shift, OP1(4), q, MOD(5), p, psq);
case 4: OP1(4) = mul_mac(OP1(4), shift, OP1(3), q, MOD(4), p, psq);
case 3: OP1(3) = mul_mac(OP1(3), shift, OP1(2), q, MOD(3), p, psq);
case 2: OP1(2) = mul_mac(OP1(2), shift, OP1(1), q, MOD(2), p, psq);
case 1: OP1(1) = mul_mac(OP1(1), shift, OP1(0), q, MOD(1), p, psq);
case 0: OP1(0) = mul_mac(OP1(0), shift, zero, q, MOD(0), p, psq);
break;
}
}
