On 01/29/2013 12:06 PM, Blue Swirl wrote:
+static const Test test_u_data[] = {
+ { 1, 1, 0, 1 },
+ { 10000, 10000, 0, 100000000 },
+ { -1ull, 2, 1, -2ull },
Shouldn't '1' be '-1'? How can this test pass?
This is 0xffff_ffff_ffff_ffff * 2 = 0x1_ffff_ffff_ffff_fffe
with the knowledge that -1 = 0xf...f and -2 = 0xf...e.
+ { -1ull, -1ull, -2ull, 1 },
This looks buggy too.
See above.
+ { -10, -10, 0, 100 },
+ { 10000, 10000, 0, 100000000 },
+ { -1, 2, -1, -2 },
+ { 0x1122334455667788ll, 0x1122334455667788ull,
Spurious 'll', also below.
Why spurious?
+static void test_u(void)
+{
+ int i;
+
+ for (i = 0; i < ARRAY_SIZE(test_u_data); ++i) {
+ uint64_t rl, rh;
+ mulu64(&rl, &rh, test_u_data[i].a, test_u_data[i].b);
+ g_assert_cmpuint(rl, ==, test_u_data[i].rl);
This could explain why the test passes: g_assert_cmpuint() uses
unsigned ints so there is truncation from uint64_t.
Does it? It sure doesn't look like it:
#define g_assert_cmpuint(n1, cmp, n2) do { guint64 __n1 = (n1), __n2 = (n2); \
if (__n1 cmp __n2) ; else \
g_assertion_message_cmpnum
(G_LOG_DOMAIN, __FILE__, __LINE__, G_STRFUNC, \
#n1 " " #cmp " " #n2, __n1,
#cmp, __n2, 'i'); } while (0)
I see guint64 in there, thus no truncation.
+static void test_s(void)
+{
+ int i;
+
+ for (i = 0; i < ARRAY_SIZE(test_u_data); ++i) {
test_s_data
Good catch. I wasn't running all of the test_s data points.
r~
