ofw/fcode/byteload.fth

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\ Hypervisor Software File: byteload.fth
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purpose: Implements byte-load interface to FCode interpreter
copyright: Copyright 1990-2001 Sun Microsystems, Inc.  All Rights Reserved

headerless
: compile-byte  ( adr immediate? -- )
   state @ 0=  or  if  execute  else  compile,  then
;

\ Interpret FCode beginning at "adr", with successive FCode bytes
\ separated by "stride" address units.  "stride" is usually 1,
\ but may be otherwise; for example, if "stride" is 4, then the
\ FCode interpreter will fetch every fourth byte (e.g. a byte-wide
\ FCode PROM on a 32-bit justified bus).

: (byte-load)  ( adr stride -- )

   ['] compile-byte is do-byte-compile

   depth 2-  >r		\ Save stack depth

   \ Interpret byte sequence
   ['] byte-interpret catch ?dup  if  throw  then

   depth  r> - 	?dup  if
      ??cr ." Warning: Fcode sequence resulted in "
      ." a net stack depth change of "  .d  cr
      nullstring throw
   then
;

headers
: byte-load ( adr stride -- )
   new-token-tables >r
   ['] (byte-load)  catch  ?dup  if    ( adr stride err# )
      .error                           ( adr stride )
      2drop
   then
   r> old-token-tables
;
\ Support for FCode-encoded dropin drivers

: execute-buffer  ( adr len -- )
   over c@  dup  h# f0 h# f3 between  swap h# fd =  or  if
      drop  1 byte-load  exit
   then

   execute-buffer
;