feat(v4.0.0): the block words are the kernel's -- v3's way in full
Ruled 2026-10-07. BLOCK, BUFFER, UPDATE, SAVE-BUFFERS and EMPTY-BUFFERS are each one kernel request on port 0, by block number only. The node has a window of four slots in its memory, as a v3 VM has; the kernel copies blocks into it, keeps the record of which block is in which slot, and decides when a block is written (v4/system/blocks.c). The node keeps no record and gives the kernel no address, so a request cannot overwrite the node's code. When a block is written stays FORTH-79's: UPDATE marks it. When the chain of devices changes the slots are let go, as in v3. The window is 512 cells more than the two buffers were; the dictionary space ends that much lower, at 13824. MESH.md 8.5 had said, from the review, that a v3 VM's BLOCK is the kernel's buffer. It is not, and the section now says what was reported, what v3 does, and what was ruled. make -C v4 test, sanitize and hosted-check pass; amd64, aarch64 and riscv64 boot, POST 538 of 538, the same hashes on all six: logs/20261007-092835, -093112, -093456. Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
This commit is contained in:
rajames
co-authored by
Claude Opus 5.5
Claude Opus 5.5
parent
7f4d946d2e
commit
9bfd5071d2
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@@ -4,103 +4,65 @@
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\ EMPTY-BUFFERS LIST LOAD SCR BLK, and v3's FLUSH THRU and --> . Part of the
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\ compiler capsule; rests on everything before it.
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\
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\ STORAGE IS THE KERNEL'S (docs/v4.0.0/MESH.md section 8, ENGINE.md 3.3). A
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\ node only ever asks for a block by number, and it asks its kernel: with
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\ the number and the word address of 256 cells on the data stack it writes
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\ the request to port 0, where its kernel is, and when the write has been
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\ served the status is on the stack in their place -- 0 it worked, 2 it was
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\ refused, 3 there is no such block.
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\
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\ THE BUFFERS. There are two, of 256 cells each, so two blocks can be in
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\ memory at once -- one can be copied to another. A buffer is given to the
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\ block that asks for one, turn about; if it held a block that was UPDATEd,
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\ that block is written first. BLOCK and BUFFER give a byte address, as PAD
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\ and TIB are: what C@ CMOVE and TYPE take.
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\ STORAGE IS THE KERNEL'S (docs/v4.0.0/MESH.md section 8, ENGINE.md 3.3), as
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\ it is for a v3 VM. A node only ever asks for a block by number, and it
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\ asks its kernel: it writes a request to port 0, where its kernel is, and
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\ when the write has been served the answer is on the data stack. The
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\ node has a window in its memory, four slots of 256 cells; the kernel
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\ keeps the record of which block is in which slot, does the copying, and
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\ decides when a block is written. The requests (v4/include/v4/blocks.h):
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\ BLOCK# ( n -- waddr status ) the slot holding block n
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\ BUFFER# ( n -- waddr status ) a slot for block n, not read
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\ UPDATE# ( -- status ) the block last asked for is changed
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\ SAVE-BUFFERS# ( -- status ) every changed block is written
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\ EMPTY-BUFFERS# ( -- ) every slot is let go
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\ The status is 0, or 2 storage refused (error 17), or 3 there is no such
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\ block (error 13). BLOCK and BUFFER give a byte address, as PAD and TIB
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\ are: what C@ CMOVE and TYPE take.
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\
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\ Constants the loader supplies:
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\ BLOCK-READ# BLOCK-WRITE# the numbers of the kernel's two requests
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\ BUF0 BUF1 word addresses of the two buffers
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\ (B) word address of six cells: (B)+0 the block in buffer 0, or 0
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\ (B)+1 whether it has been UPDATEd (B)+2 (B)+3 the same for
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\ buffer 1 (B)+4 which buffer was asked for last, 0 or 2
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\ (B)+5 the block number while a buffer is found for it
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\ BLOCK# BUFFER# UPDATE# SAVE-BUFFERS# EMPTY-BUFFERS# the requests' numbers
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\ SCR word address of the variable: the block LIST showed last
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\ BLK (SRC) (SRC-HOOK) see input.v4
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header SCR inline : SCR' SCR ;
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header BLK inline : BLK' BLK ;
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\ ( i -- addr ) the word address of buffer i, where i is 0 or 2
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: (BUF) if Z drop BUF1 ; Z: drop BUF0 ;
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\ ( command i -- ) read buffer i's block from storage, command 1, or
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\ write it, command 2: a request of this node's kernel ( n waddr -- status ).
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\ If it did not work nothing is in the buffer, and it is an error: 17 if
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\ storage refused, 13 if there is no such block.
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: (DEVICE)
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dup push SWAP push \ i R: i command
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dup (B) + a! @ SWAP (BUF) \ n waddr
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pop -1 + if RD drop BLOCK-WRITE# jump ASK
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RD: drop BLOCK-READ#
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ASK: (PORT) b! !b \ status
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pop SWAP \ i status
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if FINE
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push (B) + a! 0 !+ 0 ! pop
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-2 + if E17 drop NODE-ERROR b! 13 !b ;
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\ ( status -- ) a request that did not work is an error
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: (B-ERR)
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if FINE -2 + if E17 drop NODE-ERROR b! 13 !b ;
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E17: drop NODE-ERROR b! 17 !b ;
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FINE: drop drop ;
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FINE: drop ;
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\ ( i -- ) if buffer i's block has been UPDATEd, write it
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: (SAVE)
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dup (B) + 1 + a! @ if CLEAN
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drop 0 ! 2 SWAP jump (DEVICE)
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CLEAN: drop drop ;
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\ ( n -- i flag ) the buffer for block n: the one that has it, flag -1; or
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\ the other of the one asked for last, its old block written if need be and
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\ n's number put on it, flag 0 -- what it holds is not block n yet. A block
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\ number below 1 is an error (code 13).
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: (FIND-BUF)
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-if POS jump BAD
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POS: if BAD
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(B)+5 a! !
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(B) a! @ (B)+5 a! @ xor if HIT0 drop
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(B)+2 a! @ (B)+5 a! @ xor if HIT2 drop
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(B)+4 a! @ 2 xor dup ! \ the other one
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dup (SAVE)
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dup (B) + a! (B)+5 b! @b !+ 0 ! \ its block now, not updated
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0 ;
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HIT0: drop 0 (B)+4 a! ! 0 -1 ;
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HIT2: drop 2 (B)+4 a! ! 2 -1 ;
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BAD: drop NODE-ERROR b! 13 !b 0 -1 ;
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\ ( waddr status -- baddr ) the slot's byte address, or the error
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: (B-GOT)
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if OK SWAP drop jump (B-ERR)
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OK: drop 2* 2* ;
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\ ( n -- baddr ) FORTH-79: the address of a buffer assigned to block n.
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\ What the buffer holds is not read from storage.
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header BUFFER
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: BUFFER (FIND-BUF) drop (BUF) 2* 2* ;
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: BUFFER BUFFER# (PORT) b! !b jump (B-GOT)
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\ ( n -- baddr ) FORTH-79: the address of a buffer that holds block n,
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\ read from storage if it is not already in one.
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header BLOCK
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: BLOCK
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(FIND-BUF) if READ drop (BUF) 2* 2* ;
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READ: drop drop \ which buffer is in (B)+4: nothing waits on the stack
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1 (B)+4 a! @ (DEVICE) (B)+4 a! @ (BUF) 2* 2* ;
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: BLOCK BLOCK# (PORT) b! !b jump (B-GOT)
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\ FORTH-79: mark the block most recently asked for as changed, so that it is
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\ written before its buffer is used for another.
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header UPDATE
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: UPDATE (B)+4 a! @ (B) + a! @+ if NONE drop -1 ! ; NONE: drop ;
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: UPDATE UPDATE# (PORT) b! !b jump (B-ERR)
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\ FORTH-79: write every block that has been UPDATEd.
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header SAVE-BUFFERS
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: SAVE-BUFFERS 0 (SAVE) 2 jump (SAVE)
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: SAVE-BUFFERS SAVE-BUFFERS# (PORT) b! !b jump (B-ERR)
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\ As v3: the same.
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header FLUSH
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: FLUSH jump SAVE-BUFFERS
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\ FORTH-79: forget what is in the buffers; nothing is written.
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header EMPTY-BUFFERS
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: EMPTY-BUFFERS (B) a! 0 !+ 0 !+ 0 !+ 0 ! ;
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: EMPTY-BUFFERS EMPTY-BUFFERS# (PORT) b! !b ;
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\ ---- LIST ----------------------------------------------------------------------
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\ ( n -- ) as v3: a new line, "Block n", then sixteen lines of 64
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