#include <linux/module.h>

/*
 * Verification test for div64_u64.
 */

#ifndef abs64
#define abs64(x) ({			\
	s64 __x = (x);			\
	(__x < 0) ? -__x : __x;		\
})
#endif

int div64_u64_test(void)
{
	u64 uu, vu, qu, ru;
	int n, i, j, errors = 0;
	const u64 tabu[] = {
	    0, 1, 2, 3, 4, 5, 6, 7, 8, 9,
	    10, 11, 12, 13, 14, 15, 16, 1000, 2003,
	    32765, 32766, 32767, 32768, 32769, 32760,
	    65533, 65534, 65535, 65536, 65537, 65538,
	    0x7ffffffeULL, 0x7fffffffULL, 0x80000000ULL, 0x80000001ULL,
	    0x7000000000000000ULL, 0x7000000080000000ULL, 0x7000000080000001ULL,
	    0x7fffffffffffffffULL, 0x7fffffff8fffffffULL, 0x7fffffff8ffffff1ULL,
	    0x7fffffff00000000ULL, 0x7fffffff80000000ULL, 0x7fffffff00000001ULL,
	    0x8000000000000000ULL, 0x8000000080000000ULL, 0x8000000080000001ULL,
	    0xc000000000000000ULL, 0xc000000080000000ULL, 0xc000000080000001ULL,
	    0xfffffffffffffffdULL, 0xfffffffffffffffeULL, 0xffffffffffffffffULL,
	};

	printk("%s", "Testing unsigned 64-bit division.\n");
	n = sizeof(tabu) / sizeof(tabu[0]);
	for (i = 0; i < n; i++) {
		for (j = 1; j < n; j++) {
			uu = tabu[i];
			vu = tabu[j];
			qu = div64_u64(uu, vu);
			ru = uu - qu * vu;
			if (qu > uu || ru >= vu) {
				printk("%016llx/%016llx != %016llx "
				   "rem %016llx\n", uu, vu, qu, ru);
				errors++;
			}
		}
	}

	if (errors) {
		printk("Failed %d/%d tests\n", errors, n * (n - 1));
	} else {
		printk("Passed all %d tests\n", n * (n - 1));
	}

	return 0;
}

void div64_u64_exit(void) { }

module_init(div64_u64_test);
module_exit(div64_u64_exit);