Fcalva/cyclone
1
0
Fork 0
mirror of https://github.com/justinethier/cyclone.git synced 2025-05-19 05:39:17 +02:00
Code Issues Projects Releases Packages Wiki Activity Actions

WIP karatsuba multiplication

Browse source
This commit is contained in:
Justin Ethier 2022-06-29 13:37:37 -04:00
parent 0227424a8c
commit 55af4bacec
1 changed files with 11 additions and 9 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

20
runtime.c
View file

@ -2494,7 +2494,7 @@ object C_bignum_simplify(object big)
/* This is currently only used by Karatsuba multiplication and
* Burnikel-Ziegler division. */
static object bignum_extract_digits(void *data, object n, object x, object start, object end)
static object bignum_extract_digits(void *data, object x, object start, object end)
{
if (obj_is_int(x)) { /* Needed? */
if (obj_obj2int(start) == 0 && (end == boolean_f || obj_obj2int(end) > 0))
@ -2669,7 +2669,8 @@ static void bignum_digits_multiply(object x, object y, object result)
static object
bignum_times_bignum_karatsuba(void *data, object x, object y, int negp)
{
object kab[C_SIZEOF_FIX_BIGNUM*15+C_SIZEOF_BIGNUM(2)*3], *ka = kab, o[18],
//object kab[C_SIZEOF_FIX_BIGNUM*15+C_SIZEOF_BIGNUM(2)*3], *ka = kab,
object o[18],
xhi, xlo, xmid, yhi, ylo, ymid, a, b, c, n, bits;
int i = 0;
@ -2677,13 +2678,13 @@ bignum_times_bignum_karatsuba(void *data, object x, object y, int negp)
// C_stack_check1(return C_SCHEME_FALSE);
//
// /* Split |x| in half: <xhi,xlo> and |y|: <yhi,ylo> with len(ylo)=len(xlo) */
// x = o[i++] = C_s_a_u_i_integer_abs(&ka, 1, x);
// y = o[i++] = C_s_a_u_i_integer_abs(&ka, 1, y);
// x = o[i++] = C_s_a_u_i_integer_abs(1, x);
// y = o[i++] = C_s_a_u_i_integer_abs(1, y);
// n = C_fix(C_bignum_size(y) >> 1);
xhi = o[i++] = bignum_extract_digits(data, &ka, 3, x, n, boolean_f);
xlo = o[i++] = bignum_extract_digits(data, &ka, 3, x, obj_int2obj(0), n);
yhi = o[i++] = bignum_extract_digits(data, &ka, 3, y, n, boolean_f);
ylo = o[i++] = bignum_extract_digits(data, &ka, 3, y, obj_int2obj(0), n);
xhi = o[i++] = bignum_extract_digits(data, x, n, boolean_f);
xlo = o[i++] = bignum_extract_digits(data, x, obj_int2obj(0), n);
yhi = o[i++] = bignum_extract_digits(data, y, n, boolean_f);
ylo = o[i++] = bignum_extract_digits(data, y, obj_int2obj(0), n);
// /* a = xhi * yhi, b = xlo * ylo, c = (xhi - xlo) * (yhi - ylo) */
// a = o[i++] = C_s_a_u_i_integer_times(&ka, 2, xhi, yhi);
@ -2703,9 +2704,10 @@ bignum_times_bignum_karatsuba(void *data, object x, object y, int negp)
// n = o[i++] = C_s_a_u_i_integer_plus(&ka, 2, x, y);
// if (C_truep(negp)) n = o[i++] = C_s_a_u_i_integer_negate(&ka, 1, n);
//
// JAE - no scratch space so believe not needed. Double-check first:
// n = move_buffer_object(ptr, kab, n);
// while(i--) clear_buffer_object(kab, o[i]);
// return n;
return n;
}