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Text File  |  1992-04-07  |  27KB  |  1 lines
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    HOW TO USE THE RAMDISK                            bp 17Aug86                                                                Die Ramdisk ist im Prinzip ein erweiterter Buffermechanismus,   der Buffer außerhalb des Forth-Systems verwaltet. Die Organi-   sation ist analog, mit der Ausnahme, daß es kein Updateflag     gibt, geänderte Blöcke also sofort auf die Diskette zurückge-   schrieben werden. Die Benutzung ist völlig transparent, am      Anfang muß nur einmal INITRAMDISK aufgerufen werden.                                                                            Die Struktur der Buffer wird auf Screen 3 dargestellt.                                                                          Die Ramdisk allokiert ihren Speicher mit MALLOC.                                                                                                                                                                                                                                                                                \ loadscreen for more buffers                         bp 17Aug86                                                                \needs 2over                    include double.scr                                                                              Onlyforth                                                                                                                       \needs 4dup                     : 4dup    2over 2over ;         \needs 4drop                    : 4drop   2drop 2drop ;         \needs user'                    : user'   ' >body c@ ;          \needs d>                       : d>      2swap d< ;                                                                            2 $B +thru                                                                                                                        1 +load    \ patch ramdisk into system                                                                                                                                                        \ patch ramdisk into System                           bp 17Aug86                                                                | : ((close  ( fcb -- fcb ...)   \ word for patch (CLOSE !!         dup flushramfile  [ Dos ' (close    >body @ , ]  ;                                                                          | : (empty-buffers   ( -- ...)   \ word for patching EMPTY-BUFFE    emptyramdisk      [ ' empty-buffers >body @ , ]  ;                                                                                                                                          ' ramdiskr/w is r/w                                             ' ((close          Dos ' (close     >body !                     ' (empty-buffers   ' empty-buffers  >body !                                                                                     save                                                            initramdisk                                                                                                                     \ Variables and Constants                             bp 10Aug86                                                                2Variable ramprev     0. ramprev 2!   \ points to first buffer  2Variable ramfirst    0. ramfirst 2!  \ start of buffer area    2Variable ramsize     0. ramsize 2!   \ length of buffer area                                                                   $408 Constant b/rambuf                                                                                                          | Code link>file   ( d1 -- d2 )   .l 4 SP ) addq                                                  Label >next  Next  end-code   | Code link>block       .l 6 SP ) addq  >next bra  end-code     | Code link>data        .l 8 SP ) addq  >next bra  end-code                                \\                                   structure of a buffer:                                          | link to next buffer | file | block | data .... |              +0                    +4     +6       +8           +1032        \ search for a buffer                                 bp 24Aug86\ D0:blk   D1:file   A0:bufadr  A1:Vorgaenger                   Label thisbuffer?                                                  4 A0 D) D1 cmp   0= IF  6 A0 D) D0 cmp   THEN  rts                                                                           Code rambuf?  ( blk file -- dadr tf \ blk file )                   2 SP D) D0 move   SP ) D1 move                                  .l ramprev r#) A0 move .w  thisbuffer? bsr                      0= IF   Label blockfound  .l 8. # A0 adda  A0 SP ) move .w                   true # SP -) move  Next  THEN                      BEGIN  .l A0 A1 move   A1 ) A0 move   0. # A0 cmpa   .w                0= IF   false # SP -) move  Next   THEN                         thisbuffer? bsr   0= UNTIL                               .l A0 ) A1 ) move                                                  ramprev r#) A0 ) move   A0 ramprev r#) move  .w              blockfound bra   end-code                                    \ read and write buffers                              b28sep86we                                                                | : readrambuf    ( adr daddr -- )   \ copy from daddr to adr        rot >absaddr  b/blk  lcmove ;                                                                                              | : writerambuf   ( adr daddr --)    \ copy from adr to daddr        rot >absaddr 2swap b/blk lcmove ;                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                          \ search for empty buffer                             bp 10Aug86                                                                \ : takerambuf    ( -- daddr )       \ get last buffer          \    ramprev  2@                                                \    BEGIN  2dup link>file l@  1+   ( empty buffer ? )          \    WHILE  2dup l2@ or             ( last buffer ? )           \    WHILE  l2@   REPEAT ;                                                                                                      | Code takerambuf  ( -- daddr )                                      .l  ramprev r#) A0 move                                      Label takeloop    .w -1  4 A0 D) cmpi                                0<> IF  .l A0 ) tst 0<>                                                IF   A0 ) A0 move  takeloop bra  THEN THEN          A0 SP -) move  Next  end-code                                                                                                                                                                 \ allocate a buffer                                   bp 24Aug86                                                                | 2Variable (daddr                                                                                                              \ | : markrambuf    ( blk file daddr  -- daddr )                \     2dup (daddr 2!  link>file l!  (daddr 2@ link>block l!     \     (daddr 2@ ;                                                                                                               | Code markrambuf   ( blk file daddr  -- daddr )  .l               SP )+ A0 move        .w  SP )+ 4 A0 D) move                     SP )+ 6 A0 D) move   .l A0 SP -) move        Next  end-code                                                                  | : makerambuf    ( adr blk file -- )  \ create a buffer            BEGIN  rambuf? 0= WHILE 2dup  takerambuf markrambuf                                     2drop  REPEAT       writerambuf ;