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4live
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work around the Diversi-DOS bugs... 

...of which there are many, but it works!
This commit is contained in:
Peter Ferrie 2016-12-02 11:28:29 -08:00
parent b22f6a5dc8
commit 0666fd5af0
1 changed files with 227 additions and 75 deletions
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src/4live.a
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@ -72,19 +72,22 @@
POSRDWRRANGE = 4
WIDTH = 40
HEIGHT = 24
LDRBASE = $2E0
INSTALLBUFFER = $239 ; yes, the overlay overwrites the loader...
LDRBASE = $2E9
INSTALLBUFFER = $23B ; yes, the overlay overwrites the loader...
; see also "warning!" below
SWAPBUFFER = $900 ; (LoadSaveEnd - LoadSaveStart) size
; needed by DiversiDOS, must be page-aligned
; needed by Diversi-DOS, must be page-aligned
; region is preserved across calls
; do not set below $900 if *size* of buffer is not page-aligned
SWAPSIZEALIGNED = 0 ; set to 1 if (LoadSaveEnd - LoadSaveStart) size is page-aligned
; an aligned size reduces code size by a bit but increases memory usage by a lot
*=LDRBASE-4
LdrHeader
!word LDRBASE, LdrEnd - LdrStart
;loader loads to pages 2-3, loads discardable install code also to pages 2-3
;and carries proxy routines including file manager and banked RAM exchange for DiversiDOS
;and carries proxy routines including file manager and banked RAM exchange for Diversi-DOS
LdrStart
;set filename pointer in MLI request packet
@ -228,22 +231,14 @@ BankInRAM1
bit LCBANK1
rts
;write size must be one less than required value because of course it must
WriteFile
lda ReadWriteCmd
lsr ;read has bit 0 set, write does not
bcs ReadFile
;;we are not now writing any page-aligned sizes
;; lda WriteSize
;; bne +
;; dec WriteSize + 1
;;+
dec WriteSize
;read file content into memory
;with swapping of the memory contents in Diversi-DOS,
;in order to preserve the original memory region
ReadFile
jsr ExchangeBanked1
ReadFileNoXchg
WriteFile
jsr DOSMLI
!byte ReadMLI_e - ReadMLI_b
ReadMLI_b
@ -262,16 +257,16 @@ WriteSize
ReadBuffer
WriteBuffer
!word LoadSaveStart ;buffer, self-modified in DiversiDOS
!word LoadSaveStart ;buffer, self-modified in Diversi-DOS
ReadMLI_e
;fall through to ExchangeBanked1
;swap banked dynamic region with spare region also in banked memory
;call again to restore the banked dynamic region
;swap banked memory region with main memory region
;call again to restore the main memory region
;sorry, I couldn't find a simpler way...
ExchangeBanked1
rts ;self-modified to CLC in DiversiDOS environment
rts ;self-modified to CLC in Diversi-DOS environment
;fill banked dynamic region with spaces
@ -284,6 +279,8 @@ ClearVirtualBuffer ;called with carry set
sta OPSRC1L
lda #<LastLine
;can also swap banked dynamic region with spare region also in banked memory
ExchangeBankedSet ;called with A=buffer offset, carry clear
sta OPDST1L
@ -307,7 +304,7 @@ ExchangeBankedPatch
rts
LdrEnd
!if (LdrEnd > $3D0) {
!error "page 3 swap-code too large, ", LdrEnd - $3D0, " bytes too many"
!error "LDRBASE too high, change to ", LdrStart + $3D0 - LdrEnd
} else {
!if (LdrEnd < $3D0) {
!error "LDRBASE too low, change to ", LdrStart + $3D0 - LdrEnd
@ -316,22 +313,23 @@ LdrEnd
;install routine is an overlay that is loaded by loader routine above
;loads editor code and data file into banked RAM either directly for DOS 3.3
;or via RAM exchange for DiversiDOS
;or via RAM exchange for Diversi-DOS
!pseudopc INSTALLBUFFER {
InstallStart
;check for DiversiDOS
;check for Diversi-DOS
pla
eor #$BF
pha
bne + ;regular DOS
sta ReadBuffer
lda #>SWAPBUFFER
sta ReadBuffer + 1
sta InstallReadBuffer + 1
lda #$18 ;CLC
sta ExchangeBanked1
sta ExchangeBanked2
sta ExchangeBanked1
+
;enable reading directly into banked RAM
@ -340,7 +338,11 @@ InstallStart
;read second overlay to banked RAM
jsr ReadEditor
pla
bne +
lda #$90
sta PatchDiversi
+
;open source file and read header if available
jsr LoadSaveHeader
@ -354,7 +356,7 @@ InstallStart
;set to true if no data file found (carry is set)
rol ClearOnFirstKeypress + 1
rol EnableAddPage + 1
rol PreventAddPage + 1 ;tri-state flag because Diversi-DOS
jsr SetTextCoords1
@ -372,7 +374,7 @@ InstallStart
beq +
lda #INVSPACE
sta CharDel + 1
lda #("z" + 1)
lda #$DF
sta CharMap1 + 1
sta CharMap2 + 1
+
@ -380,26 +382,23 @@ InstallStart
ldy #0
beq ++
CharMap1
cmp #0 ;self-modified in Apple II+ environment
bcs +
cmp #"a"
- cmp #$E0
bcc +
and #$DF
CharMap1
and #$FF ;self-modified in Apple II+ environment
+ jsr COUT
++ iny
lda _WelcomeMessage-1,y
bne CharMap1
;;warning! takes advantage of the fact that the hook is at $300!
;;but this cannot be detected as assemble time because of the forward reference
;; !if <GlobalKeyboardHook {
;; lda #<GlobalKeyboardHook
;; }
bne -
lda #<GlobalKeyboardHook
sta KSWL
lda #>GlobalKeyboardHook
sta KSWH
jmp WARMDOS ;DOS will reconnect the vector itself
;read the main code into banked RAM
;uses the memory swapping technique in Diversi-DOS
ReadEditor
jsr ExchangeBanked2
lda #$20 ;JSR
@ -417,10 +416,10 @@ InstallReadMLI_b
InstallReadBuffer
!word $D000 ;buffer
InstallReadMLI_e
;fall through to ExchangeBanked2
;fall through to restore buffer
ExchangeBanked2
rts ;self-modified to CLC (for compatibility) in DiversiDOS environment
rts ;self-modified to CLC (for compatibility) in Diversi-DOS environment
lda #>($D000 - <(BankedCopyStart - BankedCopyEnd))
sta OPDST1H
ldx #>(BankedCopyEnd - BankedCopyStart)
@ -477,11 +476,12 @@ RunFromBankedRAM
;first, scroll the edit buffer onto the screen
;(this also swaps the current screen contents out so we can restore it later)
jsr ScrollEditBufferIn ;returns Y=FF
;do the thing
iny
iny ;Y=0
sty WriteIfDirty2 + 1 ;0=false, non-0=true
;do the thing
@ -520,12 +520,13 @@ ScrollEditBufferIn
ldy #(WIDTH - 1)
- lda (OPDST1L), y
jsr CharMap2
jsr MapCase
sta $0400, y
dey
bpl -
;animation delay
jsr Delay
lda #-WIDTH
@ -566,12 +567,11 @@ AToScr ;called with A=dec value to print
dey
rts
CharMap2
cmp #0 ;self-modified in Apple II+ environment
bcs +
cmp #"a"
MapCase
cmp #$E0
bcc +
and #$DF
CharMap2
and #$FF ;self-modified in Apple II+ environment
+ rts
ScrollEditBufferOut
@ -599,6 +599,7 @@ ScrollEditBufferOut
bpl -
;animation delay
jsr Delay ;returns A=0
tay
@ -683,6 +684,8 @@ CopyRow
Delay
lda #1
;straight from ROM
MyWAIT
sec
-- pha
@ -696,6 +699,8 @@ MyWAIT
MyKEYIN
ldx MyCH + 1
;fetch the character at the current cursor position
ScreenBuff2
lda $34f3, x ;self-modified
sta ToggleChar + 1
@ -761,18 +766,21 @@ EditorMode
+ cpx #(IgnoreDirty - KeyTable_b)
;save result in carry
;the first keypress that clears the screen is also a trigger that the first page is dirty
;we require this trigger to allow us to work around a bug in Diversi-DOS
ClearOnFirstKeypress
ldy #0 ;self-modified
beq +
dec ClearOnFirstKeypress + 1
php ;save carry (don't care about the rest)
pha
jsr ClearScreen
jsr ClearScreen ;returns Y=FF
sty PreventAddPage + 1 ;trigger first write
pla
plp ;restore carry
+ bcc DispatchCommand
sta WriteIfDirty2 + 1
sta EnableAddPage + 1
sta WriteIfDirty2 + 1 ;remember if page was modified in the general case
DispatchCommand
jsr $34f3 ;self-modified, currently both bytes
@ -807,16 +815,16 @@ ScreenBuff4
ldx #0
MyCV
ldy #"Q" ;self-modified
iny
iny ;move to next line on horizontal typed wraparound
cpy #(HEIGHT - 1)
bne MyBASCALC
dey
bne MyBASCALC ;always
ldy #0 ;move to top left on vertical typed wraparound
beq MyBASCALC ;always
HandleKeyLineLeft
dec MyCH + 1
bpl DispatchReturn
lda #(WIDTH - 1)
lda #(WIDTH - 1) ;wrap to same line on horizontal arrow wraparound
SetColumn
sta MyCH + 1
@ -827,7 +835,7 @@ HandleKeyLineRight
lda MyCH + 1
eor #WIDTH ;zero on match
bne DispatchReturn
beq SetColumn ;always
beq SetColumn ;always, wrap to same line on horizontal arrow wraparound
HandleKeyLineUp
ldy MyCV + 1
@ -861,7 +869,7 @@ HandleKeyClearScreen
HandleKeyReturn
lda #0
sta MyCH + 1
sta MyCH + 1 ;move to left of next line on return
;fall through
HandleKeyLineDown
@ -888,7 +896,7 @@ HandleKeyImportScreen ;called with carry set
ldx #(HEIGHT - 2)
-- jsr SetTextCalc
ldy #(WIDTH - 1)
lda #$A0
lda #SPACE
- bcc + ;ClearScreen path
lda (OPSRC1L), y
+ sta (OPSRC2L), y
@ -912,10 +920,26 @@ PageReturn
;then select that page
HandleKeyAddPage
EnableAddPage
PreventAddPage
lda #0 ;self-modified
beq PageReturn ;no add until page 1 is written to disk
lda Pages + 1
beq + ;page 1 exists already, go directly to add
bpl PageReturn ;page 1 doesn't exist and nothing to write
;Diversi-DOS (not DOS 3.3) has a critical bug when writing to a newly-created file
;if the first write occurs beyond the first sector, then no preceding entries are created in the TS list!
;instead, it leaves the entries blank, causing read errors when attempting to read earlier content
;the disk space is also not reclaimed when deleting the file because the TS list looks empty
;to work around this, we detect when we are writing to the file for the first time,
;and just force the write to occur before the page is added
jsr WriteIfDirty2 ;page 1 is ready to write for the first time
;the problem is that the wrong screen was active at the time that we wrote the initial content
;so we have to perform a second write after the screen is scrolled properly
;performance is bad, but fortunately it's a one-time thing
inc WriteIfDirty2 + 1 ;force it to write again
+ lda Pages + 1
cmp #(99 - 1) ;maximum 99 pages
beq PageReturn
jsr ExchangeVirtualBuffer
@ -980,8 +1004,14 @@ HandleKeyPrevPage
;update header to specify new page count and current page
+++ jsr LoadSaveHeader
jsr CloseFile ;work around DiversiDOS bug
jsr OpenDataFile ;by close and reopen to flush the write
;Diversi-DOS has a critical bug when reading from a just-written sector
;IT RETURNS THE ORIGINAL DATA UNLESS YOU CLOSE THE FILE AND RE-OPEN IT
;so that's what we do
jsr CloseFile
jsr OpenDataFile
dec ReadWriteCmd ;lda #CMDREAD / sta ReadWriteCmd
lda ReadBuffer
pha
@ -1021,6 +1051,8 @@ HandleKeyPrevPage
tax
jsr SetTextCoords2
;fall through to restore buffer
;copy virtual buffer to another virtual buffer
;hack existing buffer copy to redirect target,
;since it copies exactly the size that we want
@ -1028,7 +1060,7 @@ HandleKeyPrevPage
ExchangeVirtualBuffer
lda #>(TEMPBUFFER - <(LoadSaveStart - LastLine))
sta ExchangeBankedPatch + 1
clc ;enable full path even if not DiversiDOS
clc ;enable full path even if not Diversi-DOS
jsr ExchangeBanked1 + 1
lda #>(SWAPBUFFER - <(LoadSaveStart - LastLine))
sta ExchangeBankedPatch + 1
@ -1040,6 +1072,8 @@ SetPrevPage
lda Pages + 1
rts
;turn everything to inverse or normal
HandleKeyHighlight
ldx MyCV + 1
jsr SetTextCalc
@ -1065,7 +1099,7 @@ HandleKeyHighlight
;control range to normal range
cmp #$A0
cmp #SPACE
bcs +
ora #$40
@ -1235,7 +1269,7 @@ SeekReadWrite ;also writes, called with X=page to read
sta SaveCH
lda MyCV + 1
sta SaveCV
jsr WriteFile ;also ReadFile
jsr WriteFileBuff ;also used by ReadFile
CloseFile
jsr DOSMLI
@ -1248,6 +1282,7 @@ OpenReturn
rts
;open the file, load/save the page count and current page
;leaves the file open for additional accesses
LoadSaveHeader
jsr OpenDataFile
@ -1262,8 +1297,124 @@ LoadSaveHeader
sta SaveCH
lda CurPage + 1
sta SaveCV
WriteFileBuff
lda ReadWriteCmd
lsr ;read has bit 0 set, write does not
bcs JumpFileIO
PatchDiversi
bcs InitDiversiWrite ;self-modified to BCC if Diversi-DOS
;write size must be one less than required value because of course it must
AdjustWriteSize
lda WriteSize
bne +
dec WriteSize + 1
+ dec WriteSize
JumpFileIO
jmp WriteFile ;also ReadFile
;Diversi-DOS (not DOS 3.3) has a critical bug when writing within a sector
;the bug is that it does not read the original sector and then replace the data before writing
;instead, it uses the last-read sector to supply the content to replace!
;to work around this, we detect when we are writing within a sector
;that can be either the write offset is non-zero, and/or the low size is non-zero
;in either case, we perform as expected: read the original sector, replace the content, write the sector
InitDiversiWrite
jsr ExchangeSectorBuffer
lda WriteSize
sta WriteSizeLow + 1
lda WriteSize + 1
sta WriteSizeHigh + 1
lda WriteOffset
sta DiversiWriteBuffer + 1
!if SWAPSIZEALIGNED=0 {
dec WriteBuffer + 1
}
lda #<LoadSaveStart
sta DiversiReadBuffer + 1
lda #>LoadSaveStart
sta DiversiReadBuffer + 2
;disable swapping temporarily
lda #$60 ;RTS
sta ExchangeBanked1
;read the existing sector
FixDiversiWrite
ldx #0
stx ReadSize
stx ReadOffset
inx
stx ReadSize + 1
dec ReadWriteCmd ;lda #CMDREAD / sta ReadWriteCmd
jsr ReadFileNoXchg
inc ReadWriteCmd ;lda #CMDWRITE / sta ReadWriteCmd
;replace existing content
;slow copy operation, but it works
DiversiReadBuffer
lda $34f3 ;self-modified
inc DiversiReadBuffer + 1
bne DiversiWriteBuffer
inc DiversiReadBuffer + 2
DiversiWriteBuffer
sta (SWAPBUFFER - <(LoadSaveStart - LastLine)) and $FF00
;low byte is self-modified
ldx WriteSizeLow + 1
bne +
dec WriteSizeHigh + 1
+ dex
stx WriteSizeLow + 1
txa
ora WriteSizeHigh + 1
beq +
inc DiversiWriteBuffer + 1
bne DiversiReadBuffer
;reaching this path means that we copy an entire sector on next pass
;but it happens only twice currently, which seems to be acceptable
;and it reduces the complexity of the code
+
;write new sector
jsr AdjustWriteSize
inc WriteOffset + 1
WriteSizeLow
lda #"Q" ;self-modified
WriteSizeHigh
ora #"Q" ;self-modified
bne FixDiversiWrite
;re-enable swapping
!if SWAPSIZEALIGNED=0 {
inc WriteBuffer + 1
}
lda #$18 ;CLC
sta ExchangeBanked1
;fall through to restore buffer
ExchangeSectorBuffer
lda #>SECTORBUFFER
sta OPDST1H
lda #0
tax
tay
sta OPSRC1L
jmp ExchangeBankedSet
TextCalcHi
!byte $04, $04, $05, $05, $06, $06, $07, $07
!byte $04, $04, $05, $05, $06, $06, $07, $07
@ -1342,33 +1493,34 @@ SaveCV
;is the design flaw in the scrolling or the reading? you decide.
FirstLine ;lines are stored sequentially, not like text page in memory
!fill WIDTH, $A0
!fill WIDTH, SPACE
SecondLine
!if >SecondLine != >LoadSaveStart {
!error "first two lines of text buffer must not cross a page"
}
!fill WIDTH * 7, $A0
!fill WIDTH * 7, SPACE
!text " 4LIVE by 4am && qkumba "
!fill WIDTH, $A0
!fill WIDTH, SPACE
!text " Revision 03 / Serial number 161123 "
!fill WIDTH * 2, $A0
!fill WIDTH * 2, SPACE
!text " https://github.com/a2-4am/4live "
!fill WIDTH * 9, $A0
!fill WIDTH * 9, SPACE
LoadSaveEnd
!fill (WIDTH - 5), $20
!text "4LIVE"
LastLine
!fill WIDTH, $A0
!fill WIDTH, SPACE
TEMPBUFFER=(*+255) and not 255
!if (TEMPBUFFER>$DC00) {
!error "banked code is too large, ends at ", *, ", ", *-$DC00, " bytes too many"
!if (TEMPBUFFER>$DB00) {
!error "banked code is too large, ends at ", *, ", ", *-$DB00, " bytes too many"
}
SECTORBUFFER=TEMPBUFFER+$400
!if VERBOSE=1 {
!warn "banked code end=", *, ", data end=", TEMPBUFFER+$3FF, ", bytes free=", $DC00-*
!warn "banked code end=", *, ", data end=", SECTORBUFFER+$FF, ", bytes free=", $DB00-*
}
}
BankedCopyEnd