; TRAIN · one step · w := w + (target - y) · pure ASM
; LINEAR BGS->BGF->SDF · atoms EZZIE PHI THERMO on BGF · free rides · no duo
; edi=w esi=target edx=y
; eax = (w + (target-y))|1 · r8 = (target-y)|1 error
; training training · field-native · NOT multi-layer net
        mov     eax, esi
        sub     eax, edx
        mov     r8d, eax
        or      r8d, 1
        add     eax, edi
        or      eax, 1
        ret