159 lines
3.4 KiB
ArmAsm
159 lines
3.4 KiB
ArmAsm
cmd_load:
|
|
|
|
;; Parse filename
|
|
;; (we can tell the KERNAL where it is in memory directly, since the
|
|
;; KERNAL will be able to peek under ROMs to read it, since it will have
|
|
;; to be able to peek under the ROMs for SAVE and VERIFY).
|
|
;; Parse optional device #
|
|
;; Parse optional secondary address
|
|
|
|
;; XXX - C64 BASIC apparently doesn't clear variables after a LOAD in the
|
|
;; middle of a program. For safety, we do.
|
|
jsr basic_do_clr
|
|
|
|
;; XXX temporary, to set valid device number
|
|
lda #$08
|
|
sta current_device_number
|
|
|
|
;; Set filename and length
|
|
lda #$00
|
|
sta current_filename_length
|
|
|
|
;; Without tape support, LOAD must have a filename
|
|
;; (This also skips any leading spaces)
|
|
jsr basic_end_of_statement_check
|
|
bcc +
|
|
jmp do_MISSING_FILENAME_error
|
|
*
|
|
jsr basic_fetch_and_consume_character
|
|
cmp #$22
|
|
beq +
|
|
jmp do_SYNTAX_ERROR
|
|
*
|
|
;; Filename starts here so set pointer
|
|
lda basic_current_statement_ptr+0
|
|
sta current_filename_ptr+0
|
|
lda basic_current_statement_ptr+1
|
|
sta current_filename_ptr+1
|
|
|
|
;; Now search for end of line or closing quote
|
|
;; so that we know the length of the filename
|
|
getting_filename:
|
|
jsr basic_fetch_and_consume_character
|
|
cmp #$22
|
|
beq got_filename
|
|
cmp #$00
|
|
bne +
|
|
jsr basic_unconsume_character
|
|
|
|
jmp got_filename
|
|
*
|
|
inc current_filename_length
|
|
jmp getting_filename
|
|
|
|
got_filename:
|
|
|
|
;; Try to load an IEC file
|
|
lda #0 ; use supplied load address, not the one from the file
|
|
sta current_secondary_address
|
|
lda #$00 ; LOAD not verify
|
|
ldx #<$0801 ; LOAD address = $0801
|
|
ldy #>$0801
|
|
|
|
jsr $ffd5
|
|
bcc +
|
|
|
|
;; A = KERNAL error code, which also almost match
|
|
;; basic ERROR codes, so we can just copy the
|
|
;; error code to X, decrement, and handle normally
|
|
tax
|
|
dex
|
|
jmp do_basic_error
|
|
|
|
*
|
|
;; $YYXX is the last loaded address, so store it
|
|
stx basic_end_of_text_ptr+0
|
|
sty basic_end_of_text_ptr+1
|
|
|
|
;; Now relink the loaded program, as we cannot trust the line
|
|
;; links supplied. For example, the VICE virtual drive emulation
|
|
;; always supplies $0101 as the address of the next line.
|
|
jsr basic_relink_program
|
|
|
|
;; After LOADing, we either start the program from the beginning,
|
|
;; or go back to the READY prompt if LOAD was called from direct mode.
|
|
|
|
;; Reset to start of program
|
|
lda basic_start_of_text_ptr+0
|
|
sta basic_current_line_ptr+0
|
|
lda basic_start_of_text_ptr+1
|
|
sta basic_current_line_ptr+1
|
|
|
|
;; XXX - should run program if LOAD was used in program mode
|
|
jmp basic_main_loop
|
|
|
|
|
|
basic_relink_program:
|
|
|
|
;; Start by getting pointer to the first line
|
|
lda basic_start_of_text_ptr+0
|
|
sta basic_current_line_ptr+0
|
|
lda basic_start_of_text_ptr+1
|
|
sta basic_current_line_ptr+1
|
|
|
|
basic_relink_loop:
|
|
;; Is the pointer to the end of the program
|
|
ldy #1
|
|
ldx #<basic_current_line_ptr+0
|
|
jsr peek_under_roms
|
|
cmp #$00
|
|
bne +
|
|
|
|
;; End of program
|
|
rts
|
|
*
|
|
;; Now search forward to find the end of the line
|
|
;; Skip forward pointer and line number
|
|
ldy #4
|
|
end_of_line_search:
|
|
ldx #<basic_current_line_ptr+0
|
|
jsr peek_under_roms
|
|
cmp #$00
|
|
beq +
|
|
|
|
;; Not yet end of line
|
|
iny
|
|
bne end_of_line_search
|
|
|
|
;; line too long
|
|
jmp do_STRING_TOO_LONG_error
|
|
|
|
*
|
|
;; Found end of line, so update pointer
|
|
|
|
;; First, skip over the $00 char
|
|
iny
|
|
|
|
;; Now overwrite the pointer (carefully)
|
|
;;
|
|
tya
|
|
clc
|
|
adc basic_current_line_ptr+0
|
|
pha
|
|
php
|
|
ldy #0
|
|
ldx #<basic_current_line_ptr+0
|
|
jsr poke_under_roms
|
|
plp
|
|
lda basic_current_line_ptr+1
|
|
adc #0
|
|
ldy #1
|
|
jsr poke_under_roms
|
|
sta basic_current_line_ptr+1
|
|
pla
|
|
sta basic_current_line_ptr+0
|
|
|
|
|
|
|
|
jmp basic_relink_loop
|