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WIP - bignum2 simplify

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This commit is contained in:
Justin Ethier 2022-06-09 19:14:06 -07:00
parent e7c50161b5
commit a956c6fd41
2 changed files with 32 additions and 31 deletions
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1
include/cyclone/types.h
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@ -854,6 +854,7 @@ typedef struct {
#define C_bignum_digits(n) (&(((bignum2_type *)n)->sign) + 1)
#define C_bignum_size(n) (((bignum2_type *)n)->num_digits)
#define C_bignum_sign(n) (((bignum2_type *)n)->sign)
#define C_bignum_negativep(n) (((bignum2_type *)n)->sign == 1)
// TODO: covert applicable definitions below -
// #ifdef C_SIXTY_FOUR

62
runtime.c
View file

@ -2451,37 +2451,37 @@ int bignum2_num_digits(bignum2_type *bn, int radix)
* in scratch space, we mark it as reclaimable. This means any
* references to the original bignum are invalid after simplification!
*/
//C_regparm C_word C_fcall C_bignum_simplify(C_word big)
//{
// C_uword *start = C_bignum_digits(big),
// *last_digit = start + C_bignum_size(big) - 1,
// *scan = last_digit, tmp;
// int length;
//
// while (scan >= start && *scan == 0)
// scan--;
// length = scan - start + 1;
//
// switch(length) {
// case 0:
// if (C_in_scratchspacep(C_internal_bignum_vector(big)))
// C_mutate_scratch_slot(NULL, C_internal_bignum_vector(big));
// return C_fix(0);
// case 1:
// tmp = *start;
// if (C_bignum_negativep(big) ?
// !(tmp & C_INT_SIGN_BIT) && C_fitsinfixnump(-(C_word)tmp) :
// C_ufitsinfixnump(tmp)) {
// if (C_in_scratchspacep(C_internal_bignum_vector(big)))
// C_mutate_scratch_slot(NULL, C_internal_bignum_vector(big));
// return C_bignum_negativep(big) ? C_fix(-(C_word)tmp) : C_fix(tmp);
// }
// /* FALLTHROUGH */
// default:
// if (scan < last_digit) C_bignum_mutate_size(big, length);
// return big;
// }
//}
object C_bignum_simplify(object big)
{
uint32_t *start = C_bignum_digits(big),
*last_digit = start + C_bignum_size(big) - 1,
*scan = last_digit, tmp;
int length;
while (scan >= start && *scan == 0)
scan--;
length = scan - start + 1;
switch(length) {
case 0:
//if (C_in_scratchspacep(C_internal_bignum_vector(big)))
// C_mutate_scratch_slot(NULL, C_internal_bignum_vector(big));
return obj_int2obj(0);
case 1:
tmp = *start;
if (C_bignum_negativep(big) ?
!(tmp & C_INT_SIGN_BIT) && C_fitsinfixnump(-(C_word)tmp) :
C_ufitsinfixnump(tmp)) {
if (C_in_scratchspacep(C_internal_bignum_vector(big)))
C_mutate_scratch_slot(NULL, C_internal_bignum_vector(big));
return C_bignum_negativep(big) ? C_fix(-(C_word)tmp) : C_fix(tmp);
}
/* FALLTHROUGH */
default:
if (scan < last_digit) C_bignum_mutate_size(big, length);
return big;
}
}
static uint32_t bignum_digits_destructive_scale_down(uint32_t *start, uint32_t *end, uint32_t denominator)
{