a2d/desktop/invoker.s

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2018-01-07 19:45:52 +00:00
.setcpu "6502"
.include "apple2.inc"
.include "../inc/apple2.inc"
.include "../inc/prodos.inc"
;;; ==================================================
;;; Segment loaded into MAIN $290-$3EF
;;; ==================================================
;;; Used to invoke other programs (system, binary, BASIC)
.proc invoker
.org $290
PREFIX := $220
FILENAME := $280 ; File to invoke, set by caller
start:
jmp begin
;;; ==================================================
default_start_address := $2000
.proc set_prefix_params
params: .byte 1
path: .addr PREFIX
.endproc
prefix_length:
.byte 0
.proc open_params
params: .byte 3
path: .addr FILENAME
buffer: .addr $800
ref_num:.byte 1
.endproc
.proc read_params
params: .byte 4
ref_num:.byte 0
buffer: .addr default_start_address
request:.word $9F00
trans: .word 0
.endproc
.proc close_params
params: .byte 1
ref_nun:.byte 0
.endproc
.proc get_info_params
params: .byte $A
path: .addr FILENAME
access: .byte 0
type: .byte 0
auxtype:.word 0
storage:.byte 0
blocks: .word 0
mod_date: .word 0
mod_time: .word 0
create_date: .word 0
create_time: .word 0
.endproc
.res 3
bs_path:
PASCAL_STRING "BASIC.SYSTEM"
.proc quit_params
params: .byte 4
.byte $EE ; nonstandard ???
.word FILENAME ; nonstandard ???
.byte 0
.word 0
.endproc
;;; ==================================================
set_prefix:
MLI_CALL SET_PREFIX, set_prefix_params
beq :+
pla
pla
jmp exit
: rts
;;; ==================================================
open: MLI_CALL OPEN, open_params
rts
;;; ==================================================
begin: lda ROMIN2
lda #<default_start_address
sta jmp_addr
lda #>default_start_address
sta jmp_addr+1
;; clear system memory bitmap
ldx #BITMAP_SIZE-2
lda #0
: sta BITMAP,x
dex
bne :-
jsr set_prefix
lda PREFIX
sta prefix_length
MLI_CALL GET_FILE_INFO, get_info_params
beq :+
jmp exit
: lda get_info_params::type
cmp #FT_S16
bne not_s16
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jsr update_bitmap
jmp quit_call
not_s16:
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cmp #FT_BINARY
bne not_binary
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lda get_info_params::auxtype
sta jmp_addr
sta read_params::buffer
lda get_info_params::auxtype+1
sta jmp_addr+1
sta read_params::buffer+1
cmp #$0C ; If loading at page < $0C
bcs :+
lda #$BB ; ... use a high address buffer ($BB)
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sta open_params::buffer+1
bne load_target ; always
: lda #$08 ; ... otherwise a low address buffer ($08)
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sta open_params::buffer+1
bne load_target ; always
not_binary:
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cmp #FT_BASIC ; BASIC?
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bne load_target
;; Invoke BASIC.SYSTEM as path instead.
lda #<bs_path
sta open_params::path
lda #>bs_path
sta open_params::path+1
;; Try opening BASIC.SYSTEM with current prefix.
check_for_bs:
jsr open
beq found_bs
ldy PREFIX ; Pop a path segment to try
: lda PREFIX,y ; parent directory.
cmp #'/'
beq update_prefix
dey
cpy #1
bne :-
jmp exit
update_prefix: ; Update prefix and try again.
dey
sty PREFIX
jsr set_prefix
jmp check_for_bs
found_bs:
lda prefix_length
sta PREFIX
jmp do_read
load_target:
jsr open
bne exit
do_read:
lda open_params::ref_num
sta read_params::ref_num
MLI_CALL READ, read_params
bne exit
MLI_CALL CLOSE, close_params
bne exit
;; If it's BASIC, set prefix and copy filename to interpreter buffer.
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lda get_info_params::type
cmp #FT_BASIC
bne update_stack
jsr set_prefix
ldy FILENAME
: lda FILENAME,y
sta $2006,y
dey
bpl :-
;; Set return address to the QUIT call below
update_stack:
lda #>(quit_call-1)
pha
lda #<(quit_call-1)
pha
jsr update_bitmap
jmp_addr := *+1
jmp default_start_address
quit_call:
MLI_CALL QUIT, quit_params
;; Update system bitmap
update_bitmap:
lda #%00000001 ; ProDOS global page
sta BITMAP+BITMAP_SIZE-1
lda #%11001111 ; ZP, Stack, Text Page 1
sta BITMAP
rts
exit: rts
;; Pad to $160 bytes
.res $160 - (* - start), 0
.endproc ; invoker