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\ Hypervisor Software File: receive.fth
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id: @(#)receive.fth 2.10 02/08/22
purpose: Interface between IP protocol layer and network driver
copyright: Copyright 1990-2002 Sun Microsystems, Inc.  All Rights Reserved
copyright: Use is subject to license terms.

\ Interface between IP protocol layer and network driver

headerless

0 instance value ethernet-max
instance variable *buffer
0 *buffer !
instance variable buffer-use-cnt    \ Number of modules using *buffer

: bufadr,len  ( -- adr len )  *buffer @  ethernet-max   ;

: reserve-buffer ( -- )
   *buffer @ 0=  if
      " max-frame-size" get-inherited-property 0=  if
         decode-int nip nip
      else
         d# 1518	\ 6 srcadr + 6 dstadr + 2 type + 1500 data + 4 crc	
      then  to ethernet-max
      ethernet-max alloc-mem *buffer !
   then
   1 buffer-use-cnt +!
;

: release-buffer  ( -- )
   -1 buffer-use-cnt +!
   buffer-use-cnt @ 0=  if
      bufadr,len  free-mem
      0 *buffer !
   then
;

\ non-zero if something good came in, <= ethernet-max
: receive  ( -- len )
   bufadr,len  " read" $call-parent  ( -2 | actual-len )
   0 max
;

\ len' is number of bytes sent
: transmit  ( len -- len' )  *buffer @  swap  " write" $call-parent  ;

headers