mirror of
https://github.com/forth-ev/VolksForth.git
synced 2024-11-25 10:30:57 +00:00
191 lines
5.2 KiB
Forth
191 lines
5.2 KiB
Forth
\ *** Block No. 94, Hexblock 5e
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\ buffer mechanism 20Oct86 07Oct87
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User isfile 0 isfile ! \ addr of file control block
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Variable fromfile 0 fromfile !
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Variable prev 0 prev ! \ Listhead
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| Variable buffers 0 buffers ! \ Semaphor
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$408 Constant b/buf \ physikalische Groesse
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$400 Constant b/blk
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\ \\ Struktur eines Buffers: 0 : link
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\ 2 : file
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\ 4 : blocknummer
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\ 6 : statusflags
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\ 8 : Data ... 1 Kb ...
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\ Statusflag bits : 15 1 -> updated
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\ file : -1 -> empty buffer, 0 -> no fcb, direct access
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\ else addr of fcb ( system dependent )
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\ *** Block No. 95, Hexblock 5f
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\ search for blocks in memory 30Jun86
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| Variable pred
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\ DE:blk BC:file HL:bufadr
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Label thisbuffer? ( Zero = this buffer )
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H push H inx H inx M A mov C cmp 0=
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?[ H inx M A mov B cmp 0= ?[ H inx M A mov E cmp
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0= ?[ H inx M A mov D cmp ]? ]? ]? H pop ret
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Code (core? ( blk file -- adr\blk file )
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IP H mvx Ipsave shld
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user' offset D lxi UP lhld D dad
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M E mov H inx M D mov
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B pop H pop H push B push D dad xchg
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prev lhld
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thisbuffer? call 0= ?[
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\ *** Block No. 96, Hexblock 60
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\ search for blocks in memory 30Jun86
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Label blockfound
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D pop D pop 8 D lxi D dad H push ' exit @ jmp ]?
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[[ pred shld
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M A mov H inx M H mov A L mov
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H ora 0= ?[ IPsave lhld H IP mvx Next ]?
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thisbuffer? call 0= ?]
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xchg pred lhld D ldax A M mov
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H inx D inx D ldax A M mov D dcx
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prev lhld xchg E M mov H inx D M mov
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H dcx prev shld
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blockfound jmp end-code
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\ *** Block No. 97, Hexblock 61
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\ (core? 29Jun86
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\ \\
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\
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\ | : this? ( blk file bufadr -- flag )
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\ dup 4+ @ swap 2+ @ d= ;
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\
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\ | : (core? ( blk file -- dataaddr / blk file )
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\ BEGIN over offset @ + over prev @ this?
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\ IF rdrop 2drop prev @ 8 + exit THEN
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\ 2dup >r offset @ + >r prev @
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\ BEGIN dup @ ?dup 0= IF rdrop rdrop drop exit THEN
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\ dup r> r> 2dup >r >r rot this? 0=
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\ WHILE nip REPEAT
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\ dup @ rot ! prev @ over ! prev ! rdrop rdrop
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\ REPEAT ;
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\ *** Block No. 98, Hexblock 62
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\ (diskerr 29Jul86 07Oct87
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: (diskerr
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." error! r to retry " key $FF and
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capital Ascii R = not Abort" aborted" ;
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Defer diskerr
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' (diskerr Is diskerr
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Defer r/w
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\ *** Block No. 99, Hexblock 63
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\ backup emptybuf readblk 20Oct86
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| : backup ( bufaddr -- ) dup 6+ @ 0<
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IF 2+ dup @ 1+ \ buffer empty if file = -1
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IF input push output push standardi/o
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BEGIN dup 6+ over 2+ @ 2 pick @ 0 r/w
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WHILE ." write " diskerr
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REPEAT THEN 4+ dup @ $7FFF and over ! THEN drop ;
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: emptybuf ( bufaddr -- ) 2+ dup on 4+ off ;
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| : readblk ( blk file addr -- blk file addr )
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dup emptybuf
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input push output push standardi/o >r
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BEGIN over offset @ + over r@ 8 + -rot 1 r/w
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WHILE ." read " diskerr REPEAT r> ;
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\ *** Block No. 100, Hexblock 64
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\ take mark updates? core? 10Mar86 19Nov87
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| : take ( -- bufaddr) prev
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BEGIN dup @ WHILE @ dup 2+ @ -1 = UNTIL
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buffers lock dup backup ;
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| : mark ( blk file bufaddr -- blk file )
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2+ >r 2dup r@ ! offset @ + r@ 2+ ! r> 4+ off
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buffers unlock ;
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| : updates? ( -- bufaddr / flag)
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prev BEGIN @ dup WHILE dup 6+ @ 0< UNTIL ;
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: core? ( blk file -- addr /false ) (core? 2drop false ;
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\ *** Block No. 101, Hexblock 65
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\ block & buffer manipulation 20Oct86 18Nov87
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: (buffer ( blk file -- addr )
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BEGIN (core? take mark REPEAT ;
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: (block ( blk file -- addr )
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BEGIN (core? take readblk mark REPEAT ;
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Code isfile@ ( -- addr ) user' isfile D lxi
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UP lhld D dad fetch jmp end-code
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: buffer ( blk -- addr ) isfile@ (buffer ;
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: block ( blk -- addr ) isfile@ (block ;
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\ : isfile@ ( -- addr ) isfile @ ;
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\ *** Block No. 102, Hexblock 66
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\ block & buffer manipulation 05Oct87
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: update $80 prev @ 6+ 1+ ( Byte-Order! ) c! ;
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Defer save-dos-buffers
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: save-buffers ( -- ) buffers lock
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BEGIN updates? ?dup WHILE backup REPEAT save-dos-buffers
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buffers unlock ;
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: empty-buffers ( -- ) buffers lock prev
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BEGIN @ ?dup WHILE dup emptybuf REPEAT buffers unlock ;
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: flush save-buffers empty-buffers ;
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\ *** Block No. 103, Hexblock 67
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\ Allocating buffers 10Oct87
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$10000 Constant limit Variable first
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: allotbuffer ( -- )
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first @ r0 @ - b/buf 2+ u< ?exit
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b/buf negate first +! first @ dup emptybuf
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prev @ over ! prev ! ;
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: freebuffer ( -- ) first @ limit b/buf - u<
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IF first @ backup prev
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BEGIN dup @ first @ - WHILE @ REPEAT
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first @ @ swap ! b/buf first +! THEN ;
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: all-buffers BEGIN first @ allotbuffer first @ = UNTIL ;
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| : init-buffers prev off limit first ! all-buffers ;
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