Apple-2-SW
/
prodos-path
mirror of https://github.com/a2stuff/prodos-path.git
1
0
Fork 0
Code Issues Projects Releases Wiki Activity
prodos-path/path.s

476 lines
12 KiB
ArmAsm
Raw Blame History

;;; ============================================================
;;;
;;; PATH
;;;
;;; Build with: ca65 - https://cc65.github.io/doc/ca65.html
;;;
;;; ============================================================
.org $2000
.include "apple2.inc"
.include "prodos.inc"
;;; ============================================================
;;;
;;; Installed command memory structure:
;;; * 3 pages - code, path buffers
;;; TODO:
;;; * Support multi-segment path (e.g. /hd/bin:/hd/extras/bin)
;;; * Fail install if on an Integer BASIC machine
;;; * Skip leading spaces
;;; ============================================================
cmd_load_addr := $4000
max_cmd_size = $2000
;;; ============================================================
;;; Monitor ROM routines/locations
INBUF := $200 ; GETLN input buffer
CROUT := $FD8E
COUT := $FDED
MOVE := $FE2C ; call with Y=0
MOVE_SRC := $3C
MOVE_END := $3E
MOVE_DST := $42
TOKEN_NAME_TABLE := $D0D0
CASE_MASK = $DF
;;; ============================================================
;;; Install the new command
.proc installer
ptr := $06
;; Save previous external command address
lda EXTRNCMD+1
sta next_command
lda EXTRNCMD+2
sta next_command+1
;; Request a buffer for handler.
lda #handler_pages
jsr GETBUFR
bcc :+
lda #$C ; NO BUFFERS AVAILABLE
rts
: sta new_page ; A = MSB of new page
;; Reserve buffer permanently.
;; ProDOS Technical Note #9: Buffer Management Using BASIC.SYSTEM
lda RSHIMEM
sec
sbc #handler_pages
sta RSHIMEM
;; Compute move delta in pages
lda new_page
sec
sbc #>handler
sta page_delta
;; Relocatable routine is aligned to page boundary so only MSB changes
ldx #0
: txa
asl
tay
lda relocation_table+1,y
sta ptr
lda relocation_table+2,y
sta ptr+1
lda (ptr)
clc
adc page_delta
sta (ptr)
inx
cpx relocation_table
bne :-
;; Relocate
lda #<handler
sta MOVE_SRC
lda #>handler
sta MOVE_SRC+1
lda #<handler_end
sta MOVE_END
lda #>handler_end
sta MOVE_END+1
lda #0
sta MOVE_DST
lda new_page
sta MOVE_DST+1
ldy #0
jsr MOVE
;; Install new address in external command address
lda new_page
sta EXTRNCMD+2
lda #0
sta EXTRNCMD+1
;; Complete
rts
.endproc
;;; ============================================================
;;; Command Handler
;;; ============================================================
;; Align handler to page boundary for easier
;; relocation
.res $2100 - *, 0
.proc handler
ptr := $06
;; Check for this command, character by character.
ldx #0
;; TODO: skip leading spaces
nxtchr: lda INBUF,x
page_num6 := *+2 ; address needing updating
jsr to_upper_ascii
page_num1 := *+2 ; address needing updating
cmp command_string,x
bne check_if_token
inx
cpx #command_length
bne nxtchr
;; A match - indicate end of command string for BI's parser.
lda #command_length-1
sta XLEN
;; Point BI's parser at the command execution routine.
lda #<execute
sta XTRNADDR
page_num2 := *+1 ; address needing updating
lda #>execute
sta XTRNADDR+1
;; Mark command as external (zero).
lda #0
sta XCNUM
;; Set accepted parameter flags (optional name)
lda #PBitsFlags::FNOPT | PBitsFlags::FN1
sta PBITS
lda #0
sta PBITS+1
clc ; Success (so far)
rts ; Return to BASIC.SYSTEM
;;; ============================================================
check_if_token:
;; Is a PATH set?
page_num18 := *+2 ; address needing updating
lda path_buffer
beq not_ours
;; TODO: skip leading spaces
;; Ensure it's alpha
lda INBUF
page_num7 := *+2 ; address needing updating
jsr to_upper_ascii
cmp #'A'
bcc not_ours
cmp #'Z'+1
bcs not_ours
;; Check if it's a BASIC token. Based on the AppleSoft BASIC source.
;; Point ptr at TOKEN_NAME_TABLE less one page (will advance below)
lda #<(TOKEN_NAME_TABLE-$100)
sta ptr
lda #>(TOKEN_NAME_TABLE-$100)
sta ptr+1
;; These start at "-1" and are immediately incremented
ldx #$FF ; X = position in input line
ldy #$FF ; (ptr),y offset TOKEN_NAME_TABLE
;; Match loop
mloop: iny ; Advance through token table
bne :+
inc ptr+1
: inx
;; Check for match
next_char:
lda INBUF,x ; Next character
page_num8 := *+2 ; address needing updating
jsr to_upper_ascii
;; NOTE: Does not skip over spaces, unlike BASIC tokenizer
sec ; Compare by subtraction..
sbc (ptr),Y
beq mloop
cmp #$80 ; If only difference was the high bit
beq not_ours ; then it's end-of-token -- and a match!
;; Otherwise, advance to next token
next_token:
ldx #0 ; Start next match at start of input line
sloop: lda (ptr),y ; Scan table looking for a high bit set
iny
bne :+
inc ptr+1
: asl
bcc sloop ; High bit clear, keep looking
lda (ptr),y ; End of table?
bne next_char ; Nope, check for a match
beq maybe_invoke
not_ours:
sec ; Signal failure...
next_command := *+1
jmp $ffff ; Execute next command in chain
;;; ============================================================
maybe_invoke:
lda VPATH1
sta ptr
lda VPATH1+1
sta ptr+1
;; Compose path
ldx #0
ldy #1
page_num12 := *+2 ; address needing updating
: lda path_buffer+1,x
inx
sta (ptr),y
iny
page_num14 := *+2 ; address needing updating
cpx path_buffer
bne :-
lda #'/'
sta (ptr),y
iny
ldx #0
: lda INBUF,x
and #$7F
cmp #'.'
beq ok
cmp #'0'
bcc notok
cmp #'9'+1
bcc ok
cmp #'A'
bcc notok
cmp #'Z'+1
bcc ok
cmp #'a'
bcc notok
cmp #'z'+1
bcs notok
ok: sta (ptr),y
iny
inx
cpx #65 ; Maximum path length+1
bcc :-
bcs fail_gfi
notok: dey
tya
ldy #0
sta (ptr),y
;; Check to see if path exists.
lda #$A ; param length
sta SSGINFO
MLI_CALL GET_FILE_INFO, SSGINFO
beq :+
fail_gfi:
sec ; no such file - signal it's not us
rts
;; Check to see if type is CMD.
: lda FIFILID
cmp #$F0 ; CMD
bne fail_gfi ; wrong type - ignore it
;; Tell BASIC.SYSTEM it was handled.
lda #0
sta XCNUM
sta PBITS
sta PBITS+1
lda #$FF ; TODO: Signal how much of input was consumed (all?)
sta XLEN
lda #<XRETURN
sta XTRNADDR
lda #>XRETURN
sta XTRNADDR+1
;; Reserve buffer for I/O
lda #4
jsr GETBUFR
bcc :+
lda #$C ; NO BUFFERS AVAILABLE
rts
: sta OSYSBUF+1
;; Now try to open/read/close and invoke it
MLI_CALL OPEN, SOPEN
bne fail_load
lda OREFNUM
sta RWREFNUM
sta CFREFNUM
lda #<cmd_load_addr
sta RWDATA
lda #>cmd_load_addr
sta RWDATA+1
lda #<max_cmd_size
sta RWCOUNT
lda #>max_cmd_size
sta RWCOUNT+1
MLI_CALL READ, SREAD
bne fail_load
;; CLOSE call trashes lower bytes of INBUF, so stash it.
ldx #$7F
: lda INBUF,x
sta INBUF+$80,x
dex
bpl :-
MLI_CALL CLOSE, SCLOSE
jsr FREEBUFR
;; Restore it.
ldx #$7F
: lda INBUF+$80,x
sta INBUF,x
dex
bpl :-
;; Invoke command
jsr cmd_load_addr
clc ; success
rts ; Return to BASIC.SYSTEM
fail_load:
jsr FREEBUFR
lda #8 ; I/O ERROR - TODO: is this used???
sec
rts
;;; ============================================================
;;; ============================================================
execute:
;; Verify required arguments
lda FBITS
and #PBitsFlags::FN1 ; Filename?
bne set_path
;;; --------------------------------------------------
;; Show current path
ldx #0
page_num3 := *+2 ; address needing updating
: cpx path_buffer
beq done
page_num4 := *+2 ; address needing updating
lda path_buffer+1,x
ora #$80
jsr COUT
inx
bpl :-
jsr CROUT
done: clc
rts
;;; --------------------------------------------------
;; Set path
set_path:
lda VPATH1
sta ptr
lda VPATH1+1
sta ptr+1
ldy #0
lda (ptr),y
tay
: lda (ptr),y
page_num5 := *+2 ; address needing updating
sta path_buffer,y
dey
bpl :-
clc
rts
;;; ============================================================
;;; Helpers
.proc to_upper_ascii
and #$7F
cmp #'a'
bcc skip
and #CASE_MASK
skip: rts
.endproc
;;; ============================================================
;;; Data
command_string:
.byte "PATH"
command_length = *-command_string
path_buffer:
.res 65, 0
.endproc
handler_end := *-1
handler_pages = (.sizeof(handler) + $FF) / $100
next_command := handler::next_command
new_page:
.byte 0
page_delta:
.byte 0
relocation_table:
.byte (table_end - *) / 2
.addr handler::page_num1
.addr handler::page_num2
.addr handler::page_num3
.addr handler::page_num4
.addr handler::page_num5
.addr handler::page_num6
.addr handler::page_num7
.addr handler::page_num8
.addr handler::page_num12
.addr handler::page_num14
.addr handler::page_num18
table_end := *
Reference in New Issue View Git Blame Copy Permalink