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30656: prevent SIGFPE in division by -1 by multiplying instead

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This commit is contained in:
Peter Stephenson 2012-09-06 18:22:30 +00:00
parent 1f5ef83f0f
commit 361e171672
2 changed files with 29 additions and 4 deletions
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26
Src/math.c
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@ -1053,14 +1053,34 @@ op(int what)
return;
if (c.type == MN_FLOAT)
c.u.d = a.u.d / b.u.d;
else
c.u.l = a.u.l / b.u.l;
else {
/*
* Avoid exception when dividing the smallest
* negative integer by -1. Always treat it the
* same as multiplication. This still doesn't give
* numerically the right answer in two's complement,
* but treating both these in the same way seems
* reasonable.
*/
if (b.u.l == -1)
c.u.l = - a.u.l;
else
c.u.l = a.u.l / b.u.l;
}
break;
case MOD:
case MODEQ:
if (!notzero(b))
return;
c.u.l = a.u.l % b.u.l;
/*
* Avoid exception as above.
* Any integer mod -1 is the same as any integer mod 1
* i.e. zero.
*/
if (b.u.l == -1)
c.u.l = 0;
else
c.u.l = a.u.l % b.u.l;
break;
case PLUS:
case PLUSEQ: