A testcase.

negative_shift_test.c

#include <stdio.h>      /* printf */
#include <inttypes.h>   /* uint32_t */
#include <stdlib.h>     /* atoi */

typedef uint32_t u32;

char* itoab2(u32 val){
        static char buf[33] = {0};
        int i;
        if (val == 0) return (char *)"0";
        for(i=32; val && i; --i) {
                buf[i] = '0' + (val & 1);
                val >>= 1;
        }
        return &buf[i+1];
}

#define prval(a,b) printf("%10s=%#016x\t[0b%s]\n", a, b, itoab2(b));

int main(int argc, char *argv[])
{
        u32 res, mod, fshift, sshift, comp, tshift, test;
        u32 bv = atoi(argv[1]);
        mod = bv % 16;
        prval("divmod", mod);
        fshift = mod << 1;
        prval("1st shift", fshift);
        sshift = 3 << fshift;
        prval("2nd shift", sshift);
        comp = ~sshift;
        prval("complement", comp);
        tshift = 3 << comp;
        prval("3rd shift", tshift);
        res = ~tshift;
        prval("result", res);
        test = (~(3<<(~(3<<((bv%16)<<1)))));
        prval("test", test);
        test = (~(3U<<(~(3U<<((26%16)<<1U)))));
        prval("testU", test);
        return 0;
}