Something

  __asm__ __volatile__(
    "XOR %%EDX,%%EDX\n\t"	//start with index 0 AND clear carry!
    "XOR %%ECX,%%ECX\n\t"
    "MOVL $6, %%ECX\n\t"
    "MOVL $6, %%EBX\n\t"
    "addition_loop_01:\n\t"
    "MOVL (%%EDI, %%EDX, 4), %%EAX\n\t"
    "ADCL 6(%%EDI), %%EAX\n\t"
    "MOVL %%EAX, (%%EDI, %%EDX, 4)\n\t"
    "INC %%EDX\n\t"
    "INC %%EBX\n\t"
    "LOOP addition_loop_01\n\t"
);