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Fixed error in new comment.

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Tim Peters 2002-08-13 20:42:00 +00:00
parent d6974a54ab
commit cba6e96929
1 changed files with 3 additions and 4 deletions
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7
Objects/longobject.c
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@ -1786,12 +1786,11 @@ least 2*shift+2 digits, and there's not obviously enough room for the
extra two bits. We need a sharper analysis in this case. The major extra two bits. We need a sharper analysis in this case. The major
laziness was in the "the same is true of ah+al" clause: ah+al can't actually laziness was in the "the same is true of ah+al" clause: ah+al can't actually
have shift+1 digits + 1 bit unless bsize is odd and asize == bsize. In that have shift+1 digits + 1 bit unless bsize is odd and asize == bsize. In that
case, we actually have (2*shift+1)*2 - shift = 3*shift + 2 allocated digits case, we actually have (2*shift+1)*2 - shift = 3*shift+2 allocated digits
remaining, and that's obviously plenty to hold 2*shift + 2 digits + 2 bits. remaining, and that's obviously plenty to hold 2*shift+2 digits + 2 bits.
Else (bsize is odd and asize < bsize) ah and al each have at most shift digits, Else (bsize is odd and asize < bsize) ah and al each have at most shift digits,
so ah+al has at most shift digits + 1 bit, and (ah+al)*(bh+bl) has at most so ah+al has at most shift digits + 1 bit, and (ah+al)*(bh+bl) has at most
2*shift+1 digits + 2 bits, and again 2*shift+2 digits + 2 bits is 2*shift+1 digits + 2 bits, and again 2*shift+2 digits is enough to hold it.
enough to hold it.
*/ */
/* b has at least twice the digits of a, and a is big enough that Karatsuba /* b has at least twice the digits of a, and a is big enough that Karatsuba