div_u64_rem.c

#include <stdio.h>
typedef unsigned int u32;
typedef unsigned long u64;

static inline u64 div_u64_rem(u64 dividend, u32 divisor, u32 *remainder)
{
    union {
        u64 v64;
        u32 v32[2];
    } d = { dividend };
    u32 upper;

    upper = d.v32[1];
    d.v32[1] = 0;
    if (upper >= divisor) {
        d.v32[1] = upper / divisor;
        upper %= divisor;
    }
    asm ("divl %2" : "=a" (d.v32[0]), "=d" (*remainder) :
        "rm" (divisor), "0" (d.v32[0]), "1" (upper));
    return d.v64;
}

int main() {
    u64 dividend = 101;
    u32 divisor = 17;
    u32 remainder;
    u64 quoitent = div_u64_rem(dividend, divisor, &remainder);
    printf("%lu = %u * %lu + %u\n", dividend, divisor, quoitent, remainder);
    return 0;
}