anchor.diff:                                  0)
     (setf (sys.int::memref-unsigned-byte-32 (virtio-gpu-command-address gpu +virtio-gpu-transfer-to-host-2d-x+) 0) x
           (sys.int::memref-unsigned-byte-32 (virtio-gpu-command-address gpu +virtio-gpu-transfer-to-host-2d-y+) 0) y
  -        (sys.int::memref-unsigned-byte-32 (virtio-gpu-command-address gpu +virtio-gpu-transfer-to-host-2d-width+) 0) w
  -        (sys.int::memref-unsigned-byte-32 (virtio-gpu-command-address gpu +virtio-gpu-transfer-to-host-2d-height+) 0) h
  -        (sys.int::memref-unsigned-byte-32 (virtio-gpu-command-address gpu +virtio-gpu-transfer-to-host-2d-offset+) 0) (* (+ x (* y (virtio-gpu-width gpu))) 4)
  -        (sys.int::memref-unsigned-byte-32 (virtio-gpu-command-address gpu +virtio-gpu-transfer-to-host-2d-resource-id+) 0) +virtio-gpu-framebuffer-resource-id+)
  -  (virtio-gpu-issue-command gpu +virtio-gpu-transfer-to-host-2d-size+ 0 in-unsafe-context-p)
  +        (sys.int::memref-unsigned-byte-32 (virtio-gpu-command-address gpu +virtio-gpu-transfer-to-host-2d-width+) 0) width
  +        (sys.int::memref-unsigned-byte-32 (virtio-gpu-command-address gpu +virtio-gpu-transfer-to-host-2d-height+) 0) height
  +        (sys.int::memref-unsigned-byte-32 (virtio-gpu-command-address gpu +virtio-gpu-transfer-to-host-2d-offset+) 0) offset
  +        (sys.int::memref-unsigned-byte-32 (virtio-gpu-command-address gpu +virtio-gpu-transfer-to-host-2d-resource-id+) 0) resource-id)
  +  (let ((resp-type (virtio-gpu-issue-command gpu
  +                                             +virtio-gpu-transfer-to-host-2d-size+
  +                                             0)))
  +    (cond ((eql resp-type +virtio-gpu-resp-ok-nodata+)
  +           (values t nil))
  +          (t
  +           (values nil resp-type)))))
  +
  +(defun virtio-gpu-resource-flush (gpu x y width height resource-id)
     (virtio-gpu-configure-command gpu
                                   +virtio-gpu-cmd-resource-flush+
                                   0
  
positive.code: (defstruct (virtio-gpu
               (:area :wired))
    virtio-device
    irq-handler-function
    (irq-latch (make-latch "Virtio-Block IRQ Notifier"))
    request-phys
    request-virt
    scanout
  
negative.code:     (when (not (virtio-configure-virtqueues device 2))
        (setf (virtio-device-status device) +virtio-status-failed+)
        (return-from virtio-gpu-register nil))
      ;; Configuration complete, go to OK mode.
      (setf (virtio-device-status device) (logior +virtio-status-acknowledge+
                                                  +virtio-status-driver+
  