What use are highscores if they aren't saved?
With this step highscores are saved and loaded from your previously used medium (tape or disk). On startup the currently used medium is stored, save and load is done via bog standard kernal routines.
The additions for this are rather miniscule. Both save and load routines work on a continious piece of memory. Fortunately both highscore names and scores are right next to each other.
For saving note that the auto-delete function in the common floppy drive is borked. Therefore we manually delete the file first and save it afterwards.
The "S0:" in front of the file name is the special code for Scratching the file.
HIGHSCORE_DELETE_FILENAME
!text "S0:HIGHSCORE"
HIGHSCORE_DELETE_FILENAME_END
!zone SaveScores
SaveScores
;delete old save file first
lda #HIGHSCORE_DELETE_FILENAME_END - HIGHSCORE_DELETE_FILENAME
ldx #<HIGHSCORE_DELETE_FILENAME
ldy #>HIGHSCORE_DELETE_FILENAME
jsr KERNAL_SETNAM
lda #$0F ; file number 15
ldx DRIVE_NUMBER
ldy #$0F ; secondary address 15
jsr KERNAL_SETLFS
jsr $FFC0 ; call OPEN
; if carry set, the file could not be opened
bcs .ErrorDelete
ldx #$0F ; filenumber 15
jsr $FFC9 ; call CHKOUT (file 15 now used as output)
.close
lda #$0F ; filenumber 15
jsr $FFC3 ; call CLOSE
ldx #$00 ; filenumber 0
jsr $FFC9 ; call CHKOUT (reset output device)
jmp .SaveNow
.ErrorDelete
;Akkumulator contains BASIC error code
;most likely errors:
;A = $5 (DEVICE NOT PRESENT)
;... error handling for open errors ...
lda #65
sta $cc00
jmp .close
; even if OPEN failed, the file has to be closed
.SaveNow
lda #9
ldx #<HIGHSCORE_FILENAME
ldy #>HIGHSCORE_FILENAME
jsr KERNAL_SETNAM
lda #$00
ldx DRIVE_NUMBER
ldy #$00
jsr KERNAL_SETLFS
lda #<HIGHSCORE_SCORE
sta $C1
lda #>HIGHSCORE_SCORE
sta $C2
ldx #<HIGHSCORE_DATA_END
ldy #>HIGHSCORE_DATA_END
lda #$C1 ; start address located in $C1/$C2
jsr $FFD8 ; call SAVE
;if carry set, a save error has happened;
bcs .SaveError
rts
Loading the score back in means mostly inserting the corresponding load calls:
;--------------------------------------------------
;load high scores
;returns 1 if ok, 0 otherwise
;--------------------------------------------------
!zone LoadScores
LoadScores
;disable kernal messages (do not want to see load error etc.)
lda #$00
jsr KERNAL_SETMSG
;set logical file parameters
lda #15
ldx DRIVE_NUMBER
ldy #0
jsr KERNAL_SETLFS
;set filename
lda #9
ldx #<HIGHSCORE_FILENAME
ldy #>HIGHSCORE_FILENAME
jsr KERNAL_SETNAM
;load to address
lda #$00 ; 0 = load
ldx #<HIGHSCORE_SCORE
ldy #>HIGHSCORE_SCORE
jsr KERNAL_LOAD
bcs .LoadError
;flag whether ok or not is set into the Carry flag
lda #1
rts
.LoadError
lda #0
rts
