int128.h: Avoid undefined behaviours involving signed arithmetic

Add casts when we're performing arithmetic on the .hi parts of an
Int128, to avoid undefined behaviour.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>
This commit is contained in:
Peter Maydell 2014-03-28 15:12:56 +00:00 committed by Michael Tokarev
parent ee25595f01
commit 423d00c857

View File

@ -53,7 +53,7 @@ static inline Int128 int128_rshift(Int128 a, int n)
if (n >= 64) {
return (Int128) { h, h >> 63 };
} else {
return (Int128) { (a.lo >> n) | (a.hi << (64 - n)), h };
return (Int128) { (a.lo >> n) | ((uint64_t)a.hi << (64 - n)), h };
}
}
@ -78,7 +78,7 @@ static inline Int128 int128_neg(Int128 a)
static inline Int128 int128_sub(Int128 a, Int128 b)
{
return (Int128){ a.lo - b.lo, a.hi - b.hi - (a.lo < b.lo) };
return (Int128){ a.lo - b.lo, (uint64_t)a.hi - b.hi - (a.lo < b.lo) };
}
static inline bool int128_nonneg(Int128 a)