prodos-path/path.s

467 lines
12 KiB
ArmAsm

;;; ============================================================
;;;
;;; PATH
;;;
;;; Build with: ca65 - https://cc65.github.io/doc/ca65.html
;;;
;;; ============================================================
.org $2000
.include "apple2.inc"
.include "apple2.mac"
.include "prodos.inc"
;;; ============================================================
;;;
;;; Installed command memory structure:
;;; * 2 pages - code, path buffer
;;; * 2 pages - I/O buffer
;;; TODO:
;;; * Dynamically allocate I/O buffer
;;; * 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 := $06
;; Save previous external command address
lda EXTRNCMD+1
sta next_command
lda EXTRNCMD+2
sta next_command+1
;; Request a 4-page buffer - two pages for handler,
;; two pages for I/O buffer.
lda #4
jsr GETBUFR
bcc :+
lda #$C ; NO BUFFERS AVAILABLE
rts
: sta new_page ; A = MSB of new page
;; Compute move delta in pages
lda #>handler
sec
sbc new_page
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),y
clc
adc page_delta
sta (ptr),y
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
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 (Name, Slot/Drive)
lda #PBitsFlags::FN1 ; Filename
sta PBITS
lda #PBitsFlags::SD ; Slot & Drive handling
sta PBITS+1
clc ; Success (so far)
rts ; Return to BASIC.SYSTEM
;;; ============================================================
check_if_token:
;; Is a PATH set?
lda path_buffer
beq not_ours
;; Ensure it's alpha
lda INBUF
page_num7 := *+2 ; address needing updating
jsr to_upper
cmp #'A'|$80
bcc not_ours
cmp #('Z'+1)|$80
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
;; 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
;; TODO: skip leading spaces
@loop: lda (ptr),y ; Scan table looking for a high bit set
iny
bne :+
inc ptr+1
: asl
bcc @loop ; 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
.proc get_file_info_params
param_count: .byte $A
pathname: .addr command_path_buffer
access: .byte 0
file_type: .byte 0
aux_type: .word 0
storage_type: .byte 0
blocks_used: .byte 0
mod_date: .word 0
mod_time: .word 0
create_date: .word 0
create_time: .word 0
.endproc
page_num9 := get_file_info_params::pathname+1
.proc open_params
param_count: .byte 3
pathname: .addr command_path_buffer
io_buffer: .addr handler + $200
ref_num: .byte 0
.endproc
page_num10 := open_params::pathname+1
page_num11 := open_params::io_buffer+1
.proc read_params
param_count: .byte 4
ref_num: .byte 0
data_buffer: .addr cmd_load_addr
request_count: .word max_cmd_size
trans_count: .word 0
.endproc
.proc close_params
param_count: .byte 1
ref_num: .byte 0
.endproc
maybe_invoke:
;; Compose path
ldx #0
: lda path_buffer+1,x ; TODO: absolute refs
sta command_path_buffer+1,x ; TODO: absolute refs
inx
cpx path_buffer
bne :-
lda #'/'
sta command_path_buffer+1,x
inx
ldy #0
: lda INBUF,y
cmp #'.'|$80
beq @ok
cmp #'0'
bcc @notok
cmp #'9'+1
bcc @ok
cmp #'A'
bcc @notok
cmp #'Z'+1
bcc @ok
cmp #'a'
bcc @notok
cmp #'z'+1
bcs @notok
@ok: sta command_path_buffer+1,x
inx
iny
bne :-
@notok: stx command_path_buffer
jsr MLI
.byte GET_FILE_INFO
.addr get_file_info_params
beq :+
sec ; no such file - signal it's not us
rts
: lda get_file_info_params::file_type
cmp #$F0 ; CMD
beq :+
sec ; wrong type - ignore it
rts
;; 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
;; Now try to open/read/close and invoke it
jsr MLI
.byte OPEN
.addr open_params
beq :+
lda #8 ; I/O ERROR - TODO: is this used???
sec
rts
: lda open_params::ref_num
sta read_params::ref_num
sta close_params::ref_num
jsr MLI
.byte READ
.addr read_params
beq :+
lda #8 ; I/O ERROR - TODO: is this used???
sec
rts
: jsr MLI
.byte CLOSE
.addr close_params
;; Invoke command
jsr cmd_load_addr
clc ; Success
rts ; Return to BASIC.SYSTEM
;;; ============================================================
;;; ============================================================
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
ldx 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
cmp #'a'|$80
bcc skip
and #CASE_MASK
skip: rts
.endproc
;;; ============================================================
;;; Data
command_string:
scrcode "PATH"
command_length = *-command_string
path_buffer:
.res 65, 0
command_path_buffer:
.res 65, 0
.endproc
.assert .sizeof(handler) <= $200, error, "Must fit on two pages"
handler_end := *-1
next_command := handler::next_command
new_page:
.byte 0
page_delta:
.byte 0
relocation_table:
.byte 5
.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_num9
.addr handler::page_num10
.addr handler::page_num11