/* init a new mp_int */
int mp_init (mp_int * a)
{
#ifdef __UHC_BUILDS_RTS__
// all allocation is assumed to be done outside library
mp_zero(a) ;
printf( "WARNING: mp_init (%p used=%x alc=%x)\n", a, USED(a), ALLOC(a) ) ;
// prLTM(a,"mp_init") ;
#else
int i;
/* allocate memory required and clear it */
SET_DIGITS(a, OPT_CAST(mp_digit) XMALLOC (sizeof (mp_digit) * MP_PREC));
if (DIGITS(a) == NULL) {
return MP_MEM;
}
/* set the digits to zero */
for (i = 0; i < MP_PREC; i++) {
SET_DIGIT(a,i,0);
}
/* set the used to zero, allocated digits to the default precision
* and sign to positive */
SET_USED(a,0);
SET_ALLOC(a,MP_PREC);
SET_SIGN(a,MP_ZPOS);
#endif
return MP_OKAY;
}
void *malloc(ssize_t size_)
{
void *at = mem_ptr;
uint32_t size = (uint32_t)ROUNDUP(size_, BYTES_PER_LONG) + BYTES_PER_LONG;
int looped = 0;
uint32_t expand_size;
void *expanded;
/* Scan the current heap for an opening. */
while (!looped || at < mem_ptr)
{
uint32_t at_size = BLOCK_SIZE(at);
if (!IS_USED(at) && at_size >= size && at_size - size != BYTES_PER_LONG)
{ /* We can use this block. */
void *leftover = at + size;
SET_SIZE(at, size);
SET_USED(at);
SET_SIZE(leftover, at_size - size);
SET_UNUSED(leftover);
mem_ptr = leftover;
return PTR(at);
}
at += at_size;
if (at >= curr_brk)
{
at = orig_brk;
looped = 1;
}
}
/* Expand the heap. */
expand_size = size + BUFFER_SIZE;
expanded = mbrk(curr_brk + expand_size);
if (expanded != at + expand_size)
return NULL;
at = curr_brk;
curr_brk = expanded;
SET_SIZE(at, size);
SET_USED(at);
SET_SIZE(at + size, expand_size - size);
SET_UNUSED(at + size);
return PTR(at);
}
/* b = a/2 */
int mp_div_2(mp_int * a, mp_int * b)
{
int x, res, oldused;
/* copy */
if (ALLOC(b) < USED(a)) {
if ((res = mp_grow (b, USED(a))) != MP_OKAY) {
return res;
}
}
oldused = USED(b);
SET_USED(b,USED(a));
{
register mp_digit r, rr, *tmpa, *tmpb;
/* source alias */
tmpa = DIGITS(a) + USED(b) - 1;
/* dest alias */
tmpb = DIGITS(b) + USED(b) - 1;
/* carry */
r = 0;
for (x = USED(b) - 1; x >= 0; x--) {
/* get the carry for the next iteration */
rr = *tmpa & 1;
/* shift the current digit, add in carry and store */
*tmpb-- = (*tmpa-- >> 1) | (r << (DIGIT_BIT - 1));
/* forward carry to next iteration */
r = rr;
}
/* zero excess digits */
tmpb = DIGITS(b) + USED(b);
for (x = USED(b); x < oldused; x++) {
*tmpb++ = 0;
}
}
SET_SIGN(b,SIGN(a));
mp_clamp (b);
return MP_OKAY;
}
/* Karatsuba squaring, computes b = a*a using three
* half size squarings
*
* See comments of karatsuba_mul for details. It
* is essentially the same algorithm but merely
* tuned to perform recursive squarings.
*/
int mp_karatsuba_sqr (mp_int * a, mp_int * b)
{
mp_int x0, x1, t1, t2, x0x0, x1x1;
int B, err;
err = MP_MEM;
/* min # of digits */
B = USED(a);
/* now divide in two */
B = B >> 1;
/* init copy all the temps */
if (mp_init_size (&x0, B) != MP_OKAY)
goto ERR;
if (mp_init_size (&x1, USED(a) - B) != MP_OKAY)
goto X0;
/* init temps */
if (mp_init_size (&t1, USED(a) * 2) != MP_OKAY)
goto X1;
if (mp_init_size (&t2, USED(a) * 2) != MP_OKAY)
goto T1;
if (mp_init_size (&x0x0, B * 2) != MP_OKAY)
goto T2;
if (mp_init_size (&x1x1, (USED(a) - B) * 2) != MP_OKAY)
goto X0X0;
{
register int x;
register mp_digit *dst, *src;
src = DIGITS(a);
/* now shift the digits */
dst = DIGITS(&x0);
for (x = 0; x < B; x++) {
*dst++ = *src++;
}
dst = DIGITS(&x1);
for (x = B; x < USED(a); x++) {
*dst++ = *src++;
}
}
SET_USED(&x0,B);
SET_USED(&x1,USED(a) - B);
mp_clamp (&x0);
/* now calc the products x0*x0 and x1*x1 */
if (mp_sqr (&x0, &x0x0) != MP_OKAY)
goto X1X1; /* x0x0 = x0*x0 */
if (mp_sqr (&x1, &x1x1) != MP_OKAY)
goto X1X1; /* x1x1 = x1*x1 */
/* now calc (x1+x0)**2 */
if (s_mp_add (&x1, &x0, &t1) != MP_OKAY)
goto X1X1; /* t1 = x1 - x0 */
if (mp_sqr (&t1, &t1) != MP_OKAY)
goto X1X1; /* t1 = (x1 - x0) * (x1 - x0) */
/* add x0y0 */
if (s_mp_add (&x0x0, &x1x1, &t2) != MP_OKAY)
goto X1X1; /* t2 = x0x0 + x1x1 */
if (s_mp_sub (&t1, &t2, &t1) != MP_OKAY)
goto X1X1; /* t1 = (x1+x0)**2 - (x0x0 + x1x1) */
/* shift by B */
if (mp_lshd (&t1, B) != MP_OKAY)
goto X1X1; /* t1 = (x0x0 + x1x1 - (x1-x0)*(x1-x0))<<B */
if (mp_lshd (&x1x1, B * 2) != MP_OKAY)
goto X1X1; /* x1x1 = x1x1 << 2*B */
if (mp_add (&x0x0, &t1, &t1) != MP_OKAY)
goto X1X1; /* t1 = x0x0 + t1 */
if (mp_add (&t1, &x1x1, b) != MP_OKAY)
goto X1X1; /* t1 = x0x0 + t1 + x1x1 */
err = MP_OKAY;
X1X1:mp_clear (&x1x1);
X0X0:mp_clear (&x0x0);
T2:mp_clear (&t2);
T1:mp_clear (&t1);
X1:mp_clear (&x1);
X0:mp_clear (&x0);
ERR:
return err;
}
