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Copy comment about inner loop from powerpc mpa.c to the default one

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Siddhesh Poyarekar 2013-02-20 18:56:20 +05:30
parent 92945b5261
commit 20cd7fb3ae
4 changed files with 20 additions and 2 deletions
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8
ChangeLog
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@ -1,3 +1,11 @@
2013-02-20 Siddhesh Poyarekar <siddhesh@redhat.com>
* sysdeps/ieee754/dbl-64/mpa.c (__sqr): Copy over comment from
powerpc mpa.c.
* sysdeps/powerpc/powerpc32/power4/fpu/mpa.c (__mul): Fix
comment formatting.
* sysdeps/powerpc/powerpc64/power4/fpu/mpa.c (__mul): Likewise.
2013-02-19 Joseph Myers <joseph@codesourcery.com> 2013-02-19 Joseph Myers <joseph@codesourcery.com>
[BZ #13550] [BZ #13550]

10
sysdeps/ieee754/dbl-64/mpa.c
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@ -749,6 +749,15 @@ __sqr (const mp_no *x, mp_no *y, int p)
if (k % 2 == 0) if (k % 2 == 0)
yk += X[lim] * X[lim]; yk += X[lim] * X[lim];
/* In __mul, this loop (and the one within the next while loop) run
between a range to calculate the mantissa as follows:
Z[k] = X[k] * Y[n] + X[k+1] * Y[n-1] ... + X[n-1] * Y[k+1]
+ X[n] * Y[k]
For X == Y, we can get away with summing halfway and doubling the
result. For cases where the range size is even, the mid-point needs
to be added separately (above). */
for (i = k - p, j = p; i < j; i++, j--) for (i = k - p, j = p; i < j; i++, j--)
yk2 += X[i] * X[j]; yk2 += X[i] * X[j];
@ -769,6 +778,7 @@ __sqr (const mp_no *x, mp_no *y, int p)
if (k % 2 == 0) if (k % 2 == 0)
yk += X[lim] * X[lim]; yk += X[lim] * X[lim];
/* Likewise for this loop. */
for (i = 1, j = k - 1; i < j; i++, j--) for (i = 1, j = k - 1; i < j; i++, j--)
yk2 += X[i] * X[j]; yk2 += X[i] * X[j];