tests: kernel/common: avoid using compiler builtin popcount (1f8c53df) · Commits · Wenxi XU / zephyr

Not all arch has native support for __builtin_popcount() on hardware and GCC falls back in using software only implementation. However, with GCC 11, this is no longer included automatically and requires linking explicitly with libgcc.a. This is not trivial as it requires changes some linker magic and a sizable change to most linker scripts. So opt for an easy solution by implementing our own popcount in the test. Signed-off-by:

Daniel Leung <daniel.leung@intel.com>

tests/kernel/common/src/bitarray.c

+17 −2

Original line number	Diff line number	Diff line
		@@ -11,7 +11,6 @@
		#include <tc_util.h>
		#include <sys/bitarray.h>
		#include <sys/util.h>
		#include <toolchain.h>

		#ifdef CONFIG_BIG_ENDIAN
		#define BIT_INDEX(bit) ((3 - ((bit >> 3) & 0x3)) + 4*(bit >> 5))
		@@ -338,13 +337,29 @@ void alloc_and_free_predefined(void)
		"sys_bitarray_free() failed bits comparison");
		}

		static inline size_t count_bits(uint32_t val)
		{
		/* Implements Brian Kernighan’s Algorithm
		* to count bits.
		*/

		size_t cnt = 0;

		while (val != 0) {
		val = val & (val - 1);
		cnt++;
		}

		return cnt;
		}

		size_t get_bitarray_popcnt(sys_bitarray_t *ba)
		{
		size_t popcnt = 0;
		unsigned int idx;

		for (idx = 0; idx < ba->num_bundles; idx++) {
		popcnt += popcount(ba->bundles[idx]);
		popcnt += count_bits(ba->bundles[idx]);
		}

		return popcnt;

Admin message