mirror of https://github.com/mgcaret/of816.git
193 lines
3.4 KiB
Forth
193 lines
3.4 KiB
Forth
\ GoSXB ROM Filesystem
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\ Since the GoSXB has the ability to have unbanked ROM, this is much easier than a stock
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\ WDC board
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\ This ROMfs supports:
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\ * up to 255 files
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\ * name lengths up to 255 bytes,
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\ * include/included for forth text
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\ * load/loaded for FCode
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\ * AUTOSTART file automatically executed
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\ future: optionally have file access words such as open-file, read-file, and friends
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start1 hex
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." GoSXB ROMfs by M.G. ... "
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s" vocabulary ROMfs also ROMfs definitions" eval
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headerless
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\ header structure
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struct
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4 field >magic
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1 field >nentries
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0 field >catalog
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drop \ no need for struct size, catalog is variable
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\ file entry structure
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struct
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4 field >offset \ relative to >magic, if 0: no more and rest of struct invalid
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4 field >size
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1 field >namelen
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0 field >name
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constant $entry-hdr-size
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defer parse-word
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s" parse-word" $find drop to parse-word
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headers
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\ romfs location
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0 value $$romfs-addr
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[ifdef] file-access-words
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0 value $$romfs-tab
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[endif]
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\ temp vars for file I/O and such
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0 value $curentry
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: $romfs-first
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$$romfs-addr >catalog to $curentry
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;
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: $romfs-next
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$curentry dup >namelen c@ $entry-hdr-size + + to $curentry
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;
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: $romfs-entname ( -- addr len )
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$curentry >name $curentry >namelen c@
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;
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: $romfs-nfiles ( -- count )
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$$romfs-addr dup if
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>nentries c@
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then
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;
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\ scan a 65816 bank for ROMfs, every $1000 bytes
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: $romfs-find-bank ( bank -- )
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d# 16 << \ convert bank addr to upper byte
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ffff 0 do dup i + \ address to probe (middle byte)
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dup @ 5346474D = \ compare with magic
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if to $$romfs-addr leave else drop then
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1000 +loop
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drop
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;
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\ scan banks $20-$2F for ROMfs
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: $romfs-find ( -- )
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30 20 do $$romfs-addr if leave else i $romfs-find-bank then loop
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[ifdef] file-access-words
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$$romfs-addr if
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$romfs-nfiles 2* cells dup alloc-mem dup to $$romfs-tab swap erase
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then
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[endif]
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;
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[ifdef] file-access-words
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\ return address or throw exception
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: $romfs-addr ( -- addr )
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$$romfs-addr ?dup 0= if d# -37 throw then
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;
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[endif]
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external
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: romfs-list ( -- )
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$romfs-nfiles dup if
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$romfs-first
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0 do
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$romfs-entname type cr
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$romfs-next
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loop
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else
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drop
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then
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;
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: romfs-lookup ( addr len -- addr2 len2 | false )
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$romfs-nfiles dup if
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>r true -rot r>
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$romfs-first
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0 do
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dup $curentry >namelen c@ = if
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2dup $curentry >name swap comp
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0= if
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2drop drop false
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$curentry >offset @ $$romfs-addr +
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$curentry >size @
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leave
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then
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then
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$romfs-next
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loop
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rot if
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\ either
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\ 2drop
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\ or
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type ." not found!" cr
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false
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then
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else
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nip nip
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then
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;
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external
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\ See if file exists, if so, eval as text or load as FCode depending on first
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\ byte
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: ?romfs-run ( addr u -- ... )
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romfs-lookup
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dup if
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over 1+ c@ 8 = if
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\ is probably FCode
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drop 1 1 byte-load
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else
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\ is hopefully text
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eval
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then
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else
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drop \ hope it wasn't zero bytes long...
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then
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;
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: included ( c-addr u -- ... )
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romfs-lookup dup if
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eval
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else
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d# -69 throw
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then
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;
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: include ( "< >name" -- ...)
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parse-word included
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;
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: fc-loaded ( c-addr u -- ... )
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romfs-lookup dup if
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drop 1 byte-load
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else
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d# -69 throw
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then
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;
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: fc-load ( "< >name" -- ... )
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parse-word fc-loaded
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;
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headers
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$romfs-find
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s" previous definitions" eval
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." loaded!" cr
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$$romfs-addr ?dup if ." ROMfs at " u. cr then
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s" AUTOEXEC" ?romfs-run
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fcode-end
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