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Added testpow2 test, and use improved version. Issue #184.

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This commit is contained in:
Branimir Karadžić
2018-05-30 12:58:47 -07:00
parent 7a10c90e1a
commit e930ad8fa1
2 changed files with 18 additions and 6 deletions
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10
include/bx/inline/uint32_t.inl
View File

@@ -453,12 +453,10 @@ namespace bx
inline uint32_t uint32_testpow2(uint32_t _a) inline uint32_t uint32_testpow2(uint32_t _a)
{ {
const uint32_t tmp0 = uint32_not(_a); const uint32_t tmp0 = uint32_dec(_a);
const uint32_t tmp1 = uint32_inc(tmp0); const uint32_t tmp1 = uint32_xor(_a, tmp0);
const uint32_t tmp2 = uint32_and(_a, tmp1); const uint32_t tmp2 = uint32_srl(tmp1, 1);
const uint32_t tmp3 = uint32_cmpeq(tmp2, _a); const uint32_t result = uint32_cmpeq(tmp2, tmp0);
const uint32_t tmp4 = uint32_cmpneq(_a, 0);
const uint32_t result = uint32_and(tmp3, tmp4);
return result; return result;
} }

14
tests/uint32_test.cpp
View File

@@ -69,3 +69,17 @@ TEST_CASE("halfTo/FromFloat", "")
REQUIRE(orig == hff); REQUIRE(orig == hff);
} }
} }
TEST_CASE("uint32_testpow2", "")
{
uint32_t shift = 0;
for (uint32_t ii = 0; ii < UINT32_MAX; ++ii)
{
if (bx::uint32_testpow2(ii) )
{
REQUIRE(ii == 1 << shift);
++shift;
}
}
}