; NET MEM · TX+RX from pointers · local NIC stats shape
; LINEAR BGS->BGF->SDF · atoms EZZIE PHI THERMO on BGF · free rides · no duo
; rdi=tx_ptr rsi=rx_ptr
; eax = SDF ([tx]-[rx])|1 · r8 free ([tx]^[rx])|1
        mov     eax, [rdi]
        mov     r8d, eax
        mov     ecx, [rsi]
        xor     r8d, ecx
        or      r8d, 1
        sub     eax, ecx
        or      eax, 1
        ret