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Don't use zz_t's fields #309

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skirpichev wants to merge 2 commits into from
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Don't use zz_t's fields #309

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252bc2e
Don't use zz_t's digits in zz_mpmath_normalize()
skirpichev Dec 31, 2025
f5db324
Don't use zz_t's fields in zz_truediv()
skirpichev Dec 31, 2025
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72 changes: 26 additions & 46 deletions gmp.c
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Original file line number Diff line number Diff line change
Expand Up @@ -1193,8 +1193,7 @@ zz_truediv(const zz_t *u, const zz_t *v, double *res)
}

int shift = (int)(vbits - ubits);
int n = shift, whole = n / bits_per_digit;
zz_t a, b;
zz_t a, b, c;

if (zz_init(&a) || zz_init(&b) || zz_abs(u, &a) || zz_abs(v, &b)) {
/* LCOV_EXCL_START */
Expand All @@ -1204,60 +1203,41 @@ zz_truediv(const zz_t *u, const zz_t *v, double *res)
return ZZ_MEM;
/* LCOV_EXCL_STOP */
}
if (shift < 0) {
const zz_t *t = u;

u = v;
v = t;
n = -n;
whole = -whole;
}
/* -shift - 1 -shift
find shift satisfying 2 <= |a/b| < 2 */
n %= bits_per_digit;
for (zz_size_t i = v->size; i--;) {
zz_digit_t du, dv = v->digits[i];

if (i >= whole) {
if (i - whole < u->size) {
du = u->digits[i - whole] << n;
}
else {
du = 0;
}
if (n && i > whole) {
du |= u->digits[i - whole - 1] >> (bits_per_digit - n);
}
}
else {
du = 0;
}
if (du < dv) {
if (shift < 0) {
shift--;
}
break;
if (zz_init(&c) || zz_pos(&b, &c)) {
/* LCOV_EXCL_START */
tmp_clear2:
zz_clear(&c);
goto tmp_clear;
/* LCOV_EXCL_STOP */
}
if (shift <= 0) {
if (shift && zz_mul_2exp(&b, (zz_bitcnt_t)-shift, &c)) {
goto tmp_clear2; /* LCOV_EXCL_LINE */
}
if (zz_cmp(&a, &c) != ZZ_LT) {
shift--;
}
}
else {
if (zz_mul_2exp(&a, (zz_bitcnt_t)shift, &c)) {
goto tmp_clear2; /* LCOV_EXCL_LINE */
}
if (du > dv) {
if (shift >= 0) {
shift--;
}
break;
if (zz_cmp(&c, &b) != ZZ_LT) {
shift--;
}
}
zz_clear(&c);
shift += DBL_MANT_DIG;
if (shift > 0 && zz_mul_2exp(&a, (uint64_t)shift, &a)) {
if (shift > 0 && zz_mul_2exp(&a, (zz_bitcnt_t)shift, &a)) {
goto tmp_clear; /* LCOV_EXCL_LINE */
}
if (shift < 0 && zz_mul_2exp(&b, (uint64_t)-shift, &b)) {
if (shift < 0 && zz_mul_2exp(&b, (zz_bitcnt_t)-shift, &b)) {
goto tmp_clear; /* LCOV_EXCL_LINE */
}
if (zz_divnear(&a, &b, &a, NULL)) {
/* LCOV_EXCL_START */
zz_clear(&a);
zz_clear(&b);
return ZZ_MEM;
/* LCOV_EXCL_STOP */
goto tmp_clear; /* LCOV_EXCL_LINE */
}
zz_clear(&b);
(void)zz_get(&a, res);
Expand Down Expand Up @@ -2511,7 +2491,7 @@ zz_mpmath_normalize(zz_bitcnt_t prec, zz_rnd rnd, bool *negative,
if (zz_quo_2exp(man, shift - 1, man)) {
return ZZ_MEM; /* LCOV_EXCL_LINE */
}
t = zz_isodd(man) && (man->digits[0]&2 || t);
t = zz_isodd(man) && (zz_lsbpos(man) == 1 || t);
if (zz_quo_2exp(man, 1, man)) {
return ZZ_MEM; /* LCOV_EXCL_LINE */
}
Expand Down