mirror of
https://github.com/a2stuff/prodos-path.git
synced 2024-12-26 06:33:47 +00:00
WIP
This commit is contained in:
Joshua Bell
parent
42dc31e40e
commit
ed1277cc4d
171
path.s
171
path.s
@ -8,6 +8,8 @@
|
||||
|
||||
.org $2000
|
||||
|
||||
.include "apple2.inc"
|
||||
.include "apple2.mac"
|
||||
.include "prodos.inc"
|
||||
|
||||
;;; ============================================================
|
||||
@ -20,7 +22,20 @@ 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
|
||||
|
||||
;; TODO: Fail if Applesoft is not in ROM
|
||||
|
||||
;; Save previous external command address
|
||||
lda EXTRNCMD+1
|
||||
@ -28,34 +43,54 @@ COUT := $FDED
|
||||
lda EXTRNCMD+2
|
||||
sta next_command+1
|
||||
|
||||
;; Request a 1-page buffer
|
||||
lda #1
|
||||
;; Request a 2-page buffer
|
||||
lda #2
|
||||
jsr GETBUFR
|
||||
bcc :+
|
||||
lda #$C ; NO BUFFERS AVAILABLE
|
||||
rts
|
||||
:
|
||||
;; A = MSB of new page - update absolute addresses
|
||||
;; (aligned to page boundary so only MSB changes)
|
||||
: 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 relocation_table
|
||||
: ldy relocation_table+1,x
|
||||
lda handler,y
|
||||
clc
|
||||
adc page_delta
|
||||
sta handler,y
|
||||
dex
|
||||
bpl :-
|
||||
|
||||
;; 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
|
||||
|
||||
;; Relocate
|
||||
ldx #0
|
||||
: lda handler,x
|
||||
page_num3 := *+2
|
||||
sta $2100,x ; self-modified
|
||||
inx
|
||||
bne :-
|
||||
|
||||
;; Complete
|
||||
rts
|
||||
|
||||
@ -68,21 +103,19 @@ COUT := $FDED
|
||||
.res $2100 - *, 0
|
||||
|
||||
.proc handler
|
||||
ptr := $06
|
||||
|
||||
;; Check for this command, character by character.
|
||||
ldx #0
|
||||
nxtchr: lda INBUF,x
|
||||
;; TODO: skip leading spaces
|
||||
|
||||
and #$7F ; Convert to ASCII
|
||||
cmp #'a' ; Convert to upper-case
|
||||
bcc :+
|
||||
cmp #'z'+1
|
||||
bcs :+
|
||||
and #$DF
|
||||
nxtchr: lda INBUF,x
|
||||
page_num6 := *+2 ; address needing updating
|
||||
jsr to_upper
|
||||
|
||||
page_num1 := *+2 ; address needing updating
|
||||
: cmp command_string,x
|
||||
bne not_path
|
||||
cmp command_string,x
|
||||
bne check_if_token
|
||||
inx
|
||||
cpx #command_length
|
||||
bne nxtchr
|
||||
@ -115,15 +148,75 @@ nxtchr: lda INBUF,x
|
||||
|
||||
;;; ============================================================
|
||||
|
||||
not_path:
|
||||
check_if_token:
|
||||
;; 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
|
||||
|
||||
;; Not a keyword, so invoke
|
||||
|
||||
not_a_token:
|
||||
;; TODO: Implement me!
|
||||
|
||||
;;; ============================================================
|
||||
not_ours:
|
||||
sec ; Signal failure...
|
||||
next_command := *+1
|
||||
jmp $ffff ; Execute next command in chain
|
||||
|
||||
|
||||
;;; ============================================================
|
||||
;;; ============================================================
|
||||
|
||||
execute:
|
||||
@ -137,10 +230,10 @@ execute:
|
||||
;; Show current path
|
||||
|
||||
ldx #0
|
||||
page_num3 := *+2
|
||||
page_num3 := *+2 ; address needing updating
|
||||
: cpx path_buffer
|
||||
beq done
|
||||
page_num4 := *+2
|
||||
page_num4 := *+2 ; address needing updating
|
||||
lda path_buffer+1,x
|
||||
ora #$80
|
||||
jsr COUT
|
||||
@ -154,7 +247,6 @@ done: clc
|
||||
;;; --------------------------------------------------
|
||||
;; Set path
|
||||
set_path:
|
||||
ptr := $06
|
||||
lda VPATH1
|
||||
sta ptr
|
||||
ldx VPATH1+1
|
||||
@ -164,27 +256,43 @@ set_path:
|
||||
lda (ptr),y
|
||||
tay
|
||||
: lda (ptr),y
|
||||
page_num5 := *+2
|
||||
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:
|
||||
.byte "PATH" ; Command string
|
||||
scrcode "PATH"
|
||||
command_length = *-command_string
|
||||
|
||||
path_buffer:
|
||||
.res 65, 0
|
||||
|
||||
.endproc
|
||||
.assert .sizeof(handler) <= $100, error, "Must fit on one page"
|
||||
.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
|
||||
.byte <handler::page_num1
|
||||
@ -192,3 +300,6 @@ relocation_table:
|
||||
.byte <handler::page_num3
|
||||
.byte <handler::page_num4
|
||||
.byte <handler::page_num5
|
||||
.byte <handler::page_num6
|
||||
.byte <handler::page_num7
|
||||
.byte <handler::page_num8
|
||||
|
||||
Loading…
Reference in New Issue
Block a user