Subj : Re: Closing a file in Assembly on the VIC-20
To : Tilmann Hentze
From : Silver Dream !
Date : Wed Jun 30 2021 10:49 am
On 17.06.2021 13:29, Tilmann Hentze wrote:
>> main
>> lda #$07 ; Length of file name
>> ldx #<filename ; Low byte of file name location
>> ldy #>filename ; High byte of file name location
>> jsr SETNAM ; Set the name
>
>> lda #$08 ; Logical file number
>> ldx #$08 ; Device number
>> ldy #$01 ; Secondary address - $01 because saving
>> jsr SETLFS ; Set above parameters
>
> I'd switch the two previous blocks around, so that you first set up the
> channel and then set the file name.
Shouldn't make any difference. The order of the two preparatory calls is
interchangeable.
>> lda #<flash ; Low byte of start of memory block to save
>> sta $C1
>> lda #>flash ; High byte of start of memory block to save
>> sta $C2
>
>> lda #$C1 ; Pointer to location of start address
>> ldx #<(flashend+1) ; Low byte of (end of memory block + 1)
>> ldy #>(flashend+1) ; High byte of (end of memory block + 1)
>
> The high byte should probaly only increment, when the low byte is $ff.
I am not sure what are you trying to say here. This takes LO/HI bytes of
an address. Assembler takes care of both being correct.
>
>> jsr SAVE ; Perform save
>
>> lda #$08 ; Logical file number
>> jsr CLOSE ; Close the file
One needs to CLOSE() (or CLALL() in some cases) files that were
previously OPEN(). Not needed for SAVE().
