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Some very minor speedups/cleanups.

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This commit is contained in:
William Hart 2014-02-27 12:30:53 +00:00
parent cc92f1ab7e
commit d4adcd7ce6
2 changed files with 36 additions and 11 deletions
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35
mpn/generic/sb_divappr_q.c
View File

@ -108,7 +108,7 @@ mpn_sb_divappr_q (mp_ptr qp,
qn++; qn++;
dp = dp + dn - qn - 1; /* make dp length qn + 1 */ dp = dp + dn - qn - 1; /* make dp length qn + 1 */
for ( ; qn > 0; qn--) for ( ; qn > 1; qn--)
{ {
/* fetch next word */ /* fetch next word */
cy = np[0]; cy = np[0];
@ -139,8 +139,39 @@ mpn_sb_divappr_q (mp_ptr qp,
qp[qn - 1] = q; qp[qn - 1] = q;
dp++; dp++;
} }
if (qn > 0)
{
/* fetch next word */
cy = np[0];
np--;
/* rare case where truncation ruins normalisation */
if (cy > dp[1] || (cy == dp[1] && np[0] >= dp[0]))
{
__divappr_helper(qp, np - 1, dp, 1);
return qh;
}
mpir_divapprox32_preinv2(q, cy, np[0], d1inv);
/* np -= dp*q */
cy -= mpn_submul_1(np - 1, dp, 2, q);
/* correct if remainder is too large */
if (UNLIKELY(cy || np[0] >= dp[1]))
{
if (cy || mpn_cmp(np - 1, dp, 2) >= 0)
{
q++;
cy -= mpn_sub_n(np - 1, np - 1, dp, 2);
}
}
qp[0] = q;
}
np[1] = cy; np[1] = cy;
} }
else else
{ {

12
mpn/generic/tdiv_q.c
View File

@ -167,8 +167,7 @@ mpn_tdiv_q (mp_ptr qp,
} }
else /* divisor is already normalised */ else /* divisor is already normalised */
{ {
if (new_np != np) MPN_COPY (new_np, np, nn);
MPN_COPY (new_np, np, nn);
if (dn == 2) if (dn == 2)
{ {
@ -203,12 +202,7 @@ mpn_tdiv_q (mp_ptr qp,
new_np = scratch; new_np = scratch;
new_nn = 2 * qn + 1; new_nn = 2 * qn + 1;
if (new_np == np)
/* We need {np,nn} to remain untouched until the final adjustment, so
we need to allocate separate space for new_np. */
new_np = TMP_ALLOC_LIMBS (new_nn + 1);
dh = dp[dn - 1]; dh = dp[dn - 1];
if (LIKELY ((dh & GMP_NUMB_HIGHBIT) == 0)) if (LIKELY ((dh & GMP_NUMB_HIGHBIT) == 0))
{ {
@ -286,7 +280,7 @@ mpn_tdiv_q (mp_ptr qp,
} }
MPN_COPY (qp, tp + 1, qn); MPN_COPY (qp, tp + 1, qn);
if (tp[0] <= 4) if (UNLIKELY(tp[0] <= 4))
{ {
mp_size_t rn; mp_size_t rn;