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bary_mul_balance_with_mulfunc: consitify invariant variables

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This commit is contained in:
Nobuyoshi Nakada 2021-10-11 13:28:17 +09:00
parent fdf5798fa1
commit 6fa1af7ee5
Notes: git 2021-10-12 00:45:34 +09:00 
Merged: https://github.com/ruby/ruby/pull/4949
1 changed files with 11 additions and 12 deletions
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23
bignum.c
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@ -1641,11 +1641,13 @@ rb_big_sq_fast(VALUE x)
/* balancing multiplication by slicing larger argument */ /* balancing multiplication by slicing larger argument */
static void static void
bary_mul_balance_with_mulfunc(BDIGIT *zds, size_t zn, const BDIGIT *xds, size_t xn, const BDIGIT *yds, size_t yn, BDIGIT *wds, size_t wn, mulfunc_t *mulfunc) bary_mul_balance_with_mulfunc(BDIGIT *const zds, const size_t zn,
const BDIGIT *const xds, const size_t xn,
const BDIGIT *const yds, const size_t yn,
BDIGIT *wds, size_t wn, mulfunc_t *const mulfunc)
{ {
VALUE work = 0; VALUE work = 0;
size_t yn0 = yn; size_t n;
size_t r, n;
assert(xn + yn <= zn); assert(xn + yn <= zn);
assert(xn <= yn); assert(xn <= yn);
@ -1654,13 +1656,11 @@ bary_mul_balance_with_mulfunc(BDIGIT *zds, size_t zn, const BDIGIT *xds, size_t
BDIGITS_ZERO(zds, xn); BDIGITS_ZERO(zds, xn);
n = 0; n = 0;
while (yn > 0) { while (yn > n) {
BDIGIT *tds; const size_t r = (xn > (yn - n) ? (yn - n) : xn);
size_t tn; const size_t tn = (xn + r);
r = xn > yn ? yn : xn;
tn = xn + r;
if (2 * (xn + r) <= zn - n) { if (2 * (xn + r) <= zn - n) {
tds = zds + n + xn + r; BDIGIT *const tds = zds + n + xn + r;
mulfunc(tds, tn, xds, xn, yds + n, r, wds, wn); mulfunc(tds, tn, xds, xn, yds + n, r, wds, wn);
BDIGITS_ZERO(zds + n + xn, r); BDIGITS_ZERO(zds + n + xn, r);
bary_add(zds + n, tn, bary_add(zds + n, tn,
@ -1668,21 +1668,20 @@ bary_mul_balance_with_mulfunc(BDIGIT *zds, size_t zn, const BDIGIT *xds, size_t
tds, tn); tds, tn);
} }
else { else {
BDIGIT *const tds = zds + n;
if (wn < xn) { if (wn < xn) {
wn = xn; wn = xn;
wds = ALLOCV_N(BDIGIT, work, wn); wds = ALLOCV_N(BDIGIT, work, wn);
} }
tds = zds + n;
MEMCPY(wds, zds + n, BDIGIT, xn); MEMCPY(wds, zds + n, BDIGIT, xn);
mulfunc(tds, tn, xds, xn, yds + n, r, wds+xn, wn-xn); mulfunc(tds, tn, xds, xn, yds + n, r, wds+xn, wn-xn);
bary_add(zds + n, tn, bary_add(zds + n, tn,
zds + n, tn, zds + n, tn,
wds, xn); wds, xn);
} }
yn -= r;
n += r; n += r;
} }
BDIGITS_ZERO(zds+xn+yn0, zn - (xn+yn0)); BDIGITS_ZERO(zds+xn+yn, zn - (xn+yn));
if (work) if (work)
ALLOCV_END(work); ALLOCV_END(work);