diff options
| author | Ben Avison <bavison@riscosopen.org> | 2015-08-14 14:54:03 +0100 |
|---|---|---|
| committer | Ben Avison <bavison@riscosopen.org> | 2015-10-15 15:15:10 +0100 |
| commit | f709107ae2b731d23d594961cd4fac52d2df1c64 (patch) | |
| tree | bcc29e770e7276ca80353736b937526849b812f0 | |
| parent | 70680f7c4f07e1b2c96a28be1f03be6a447d0b60 (diff) | |
Resolve implementation-defined behaviour for division rounded to -infinity
The previous implementations of DIV and MOD relied upon the built-in / and %
operators performing round-to-zero. This is true for C99, but rounding is
implementation-defined for C89 when divisor and/or dividend is negative, and
I believe Pixman is still supposed to support C89.
| -rw-r--r-- | pixman/pixman-private.h | 8 |
1 files changed, 4 insertions, 4 deletions
diff --git a/pixman/pixman-private.h b/pixman/pixman-private.h index b933943..cd2d084 100644 --- a/pixman/pixman-private.h +++ b/pixman/pixman-private.h @@ -891,12 +891,12 @@ pixman_list_move_to_front (pixman_list_t *list, pixman_link_t *link) #endif /* Integer division that rounds towards -infinity */ -#define DIV(a, b) \ - ((((a) < 0) == ((b) < 0)) ? (a) / (b) : \ - ((a) - (b) + 1 - (((b) < 0) << 1)) / (b)) +#define DIV(a, b) \ + ((a) / (b) - ((a) % (b) != 0 && ((a) % (b) < 0) != ((b) < 0) ? 1 : 0)) /* Modulus that produces the remainder wrt. DIV */ -#define MOD(a, b) ((a) < 0 ? ((b) - ((-(a) - 1) % (b))) - 1 : (a) % (b)) +#define MOD(a, b) \ + ((a) % (b) + ((a) % (b) != 0 && ((a) % (b) < 0) != ((b) < 0) ? (b) : 0)) #define CLIP(v, low, high) ((v) < (low) ? (low) : ((v) > (high) ? (high) : (v))) |