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remove 32-bit limits that show up in division calculations

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(could cause overflow during certain pricing calculations)


git-svn-id: svn+ssh://svn.gnucash.org/repo/gnucash/trunk@10098 57a11ea4-9604-0410-9ed3-97b8803252fd
This commit is contained in:
Linas Vepstas 2004-06-26 16:16:56 +00:00
parent dacfb55687
commit d5668d57df
1 changed files with 15 additions and 18 deletions
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33
src/engine/gnc-numeric.c
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@ -146,16 +146,14 @@ div128 (gncint128 n, gint64 d)
quotient.lo = lo + n.lo/d;
/* Deal with low remainder bits.
* There's probably a more efficient way of doing this.
* XXX This algo breaks if the value of teh denominator
* is larger than 2 billion.
* Is there a more efficient way of doing this?
*/
guint64 rnd = quotient.lo;
rnd *= d;
rnd &= 0x7fffffff;
rnd = (n.lo & 0x7fffffff) - rnd;
rnd &= 0x7fffffff;
rnd /= d;
gncint128 mu = mult128 (quotient.lo, d);
gint64 nn = 0x7fffffffffffffffULL & n.lo;
gint64 rr = 0x7fffffffffffffffULL & mu.lo;
gint64 rnd = nn - rr;
rnd /= d;
/* ?? will this ever overflow ? */
qlo = quotient.lo;
@ -171,21 +169,20 @@ div128 (gncint128 n, gint64 d)
return quotient;
}
/** Return the remainder of a signed 128-bit number modulo a signed 64-bit,
* XXX the current algo only works for divisor values less than 1<<31
* (2 billion)
/** Return the remainder of a signed 128-bit number modulo
* a signed 64-bit. I beleive that ths algo is overflow-free,
* but should be audited some more ...
*/
static inline gint64
rem128 (gncint128 n, gint64 d)
{
gncint128 quotient = div128 (n,d);
guint64 rnd = quotient.lo;
rnd *= d;
rnd &= 0x7fffffff;
rnd = (n.lo & 0x7fffffff) - rnd;
rnd &= 0x7fffffff;
return rnd;
gncint128 mu = mult128 (quotient.lo, d);
gint64 nn = 0x7fffffffffffffffULL & n.lo;
gint64 rr = 0x7fffffffffffffffULL & mu.lo;
return nn - rr;
}
/** Return the ratio n/d reduced so that there are no common factors. */