diff options
Diffstat (limited to 'Objects/intobject.c')
| -rw-r--r-- | Objects/intobject.c | 10 |
1 files changed, 8 insertions, 2 deletions
diff --git a/Objects/intobject.c b/Objects/intobject.c index c7137df40b..b94e3e9887 100644 --- a/Objects/intobject.c +++ b/Objects/intobject.c @@ -564,8 +564,14 @@ i_divmod(register long x, register long y, "integer division or modulo by zero"); return DIVMOD_ERROR; } - /* (-sys.maxint-1)/-1 is the only overflow case. */ - if (y == -1 && x < 0 && x == -x) + /* (-sys.maxint-1)/-1 is the only overflow case. x is the most + * negative long iff x < 0 and, on a 2's-complement box, x == -x. + * However, -x is undefined (by C) if x /is/ the most negative long + * (it's a signed overflow case), and some compilers care. So we cast + * x to unsigned long first. However, then other compilers warn about + * applying unary minus to an unsigned operand. Hence the weird "0-". + */ + if (y == -1 && x < 0 && (unsigned long)x == 0-(unsigned long)x) return DIVMOD_OVERFLOW; xdivy = x / y; xmody = x - xdivy * y; |