tnum_rshift
struct tnum tnum_rshift(struct tnum a, u8 shift);
a = tnum_rshift(a, 1);
return tnum_lshift(tnum_rshift(a, 32), 32);
dst_reg->var_off = tnum_rshift(subreg, umin_val);
dst_reg->var_off = tnum_rshift(dst_reg->var_off, umin_val);