anchor.diff:  (defun scavenge-full-save-thread (thread)
     ;; Thread has stopped due to an interrupt.
     ;; Examine it, then perform normal stack scavenging.
  -  (when *gc-debug-scavenge-stack* (gc-log "Scav full-save thread..."))
  +  (when *gc-debug-scavenge-stack* (gc-log "Scav full-save thread..." thread))
     (let* ((return-address (mezzano.supervisor:thread-state-rip thread))
            (frame-pointer (mezzano.supervisor:thread-frame-pointer thread))
            (stack-pointer (mezzano.supervisor:thread-stack-pointer thread))
  
positive.code: (defun scavenge-regular-stack-frame (frame-pointer stack-pointer framep
                                       layout-address layout-length
                                       incoming-arguments pushed-values)
    ;; Scan stack slots.
    (dotimes (slot layout-length)
      (multiple-value-bind (offset bit)
  
negative.code:          (scavenge-regular-stack-frame frame-pointer stack-pointer framep
                                         layout-address layout-length
                                         incoming-arguments pushed-values)
           (cond (framep
                  (psetf return-address (memref-unsigned-byte-64 frame-pointer 1)
                         stack-pointer (+ frame-pointer 16)
                         frame-pointer (memref-unsigned-byte-64 frame-pointer 0)))
                 (t
                  ;; No frame, carefully pick out the new values.
                  (gc-log "Unwinding through no-frame function")
                  ;; Frame pointer remains unchanged.
                  ;; Return address should be above the layout variables.
                  (setf return-address (memref-unsigned-byte-64 stack-pointer layout-length))
                  ;; Stack pointer needs the return address popped off,
                  ;; and any layout variables.
                  (setf stack-pointer (+ stack-pointer (* (1+ layout-length) 8)))))))))
  
  (defun scavenge-thread-data-registers (thread)
    (scavengef (mezzano.supervisor:thread-state-r8-value thread))
  