Posted By
Harry Potter
on 2022-06-28
10:10:35
|  Bug in Plus4Cart03/cc65
Hi! I already have two Plus4 cartridge configurations for the Plus4: one for a 16k cartridge and one for a 32k cartridge to treat the upper 16k as hidden data via a port of my Hidden64 library. Now, I am working on a 32k cartridge where the whole 32k is accessible and kernal access is delegated. It has a bug: the first time it is run, it works. The demo is doing everything it's supposed to do. However, when I exit the program, the first piece of text is displayed, but the first key press doesn't register. Following is the crt0.s code:
--------------------------
startup:
;Thi
sei
ldx #$ff
txs
lda $fb
pha
;ldx #$02 ; cartrige 1 lo, kernal
sta $FDD2
jsr $FF84 ; Initialize I/O devices
jsr $FF87 ; RAM Test
pla
sta $FB
jsr $FF8A ; Restore vectors to initial values
jsr $FF81 ; Initialize screen editor
cli
; Switch to second charset
lda #14
jsr $FFD2
; Clear the BSS data
jsr zerobss
;lda #<(__RAM_START__ + __RAM_SIZE__)
lda #$00
sta sp
;lda #>(__RAM_START__ + __RAM_SIZE__)
lda #$80
sta sp+1 ; Set argument stack ptr
lda #$03
sta $FF0C
lda #$FF
sta $FF0D
sta $FDD2 ; Enable the ROM
; If we have IRQ functions, chain our stub into the IRQ vector
; lda #<__INTERRUPTOR_COUNT__
; beq NoIRQ1
; lda IRQVec
; ldx IRQVec+1
; sta IRQInd+1
; stx IRQInd+2
; lda #; ldx #>IRQStub
; sei
; sta IRQVec
; stx IRQVec+1
; cli
; Call module constructors
NoIRQ1:
lda #<__DATA_RUN__
ldx #>__DATA_RUN__
jsr pushax
lda #<__DATA_LOAD__
ldx #>__DATA_LOAD__
jsr pushax
lda #<__DATA_SIZE__
ldx #>__DATA_SIZE__
jsr _memcpy
jsr initlib
; Push arguments and call main
;ra:
; inc $D021
; jmp ra
jsr _main
; Back from main (This is also the _exit entry). Run module destructors
_exit: jsr donelib
; Reset the IRQ vector if we chained it.
; ;pha ; Save the return code on stack
; lda #<__INTERRUPTOR_COUNT__
; beq NoIRQ2
; lda IRQInd+1
; ldx IRQInd+2
; sei
; sta IRQVec
; stx IRQVec+1
; cli
NoIRQ2:
jmp startup
------------------------------
The write.s code:
-----------------------------
;--------------------------------------------------------------------------
; initstdout: Open the stdout and stderr file descriptors for the screen.
.segment "ONCE"
.proc initstdout
lda #STDOUT_FILENO + LFN_OFFS
jsr @L1
lda #STDERR_FILENO + LFN_OFFS
@L1: ldx #CBMDEV_SCREEN
ldy #$FF
sta $FDD2
jsr SETLFS
jsr OPEN ; Will always succeed
sta $FDDA
rts
.endproc
;--------------------------------------------------------------------------
; _write
;.code
.segment "LOWCODE"
.proc _write
jsr rwcommon ; Pop params, check handle
bcs invalidfd ; Invalid handle
; Check if the LFN is valid and the file is open for writing
adc #LFN_OFFS ; Carry is already clear
tax
lda fdtab-LFN_OFFS,x; Get flags for this handle
and #LFN_WRITE ; File open for writing?
beq invalidfd
; Valid lfn. Make it the output file
sta $FDD2
jsr CKOUT
bcc @L2
@error: jmp __mappederrno ; Store into __oserror, map to errno, return -1
; Output the next character from the buffer
@L0: ldy #0
sta $FDDA
lda (ptr1),y
inc ptr1
bne @L1
inc ptr1+1 ; A = *buf++;
@L1: sta $FDD2
jsr BSOUT
; Check the status
pha
jsr READST
lsr a ; Bit zero is write timeout
bne devnotpresent2
pla
bcs @L3
; Count characters written
inc ptr3
bne @L2
inc ptr3+1
; Decrement count
@L2: dec ptr2
bne @L0
dec ptr2+1
bne @L0
; Wrote all chars or disk full. Close the output channel
@L3: jsr CLRCH
; Clear _oserror and return the number of chars written
lda #0
sta __oserror
lda ptr3
ldx ptr3+1
sta $FDDA
rts
; Error entry: Device not present
devnotpresent2:
pla
devnotpresent:
lda #ENODEV
.byte $2C ; Skip next opcode via BIT
; Error entry: The given file descriptor is not valid or not open
invalidfd:
lda #EBADF
jmp __directerrno ; Sets _errno, clears _oserror, returns -1
.endproc
----------------------
and the key press code:
----------------------
.proc _getkey
sta $FDD2
@lp:
jsr $ffe4 ;Call the getin kernal routine to
;get the key-press.
cmp #0 ;Continue until key pressed.
beq @lp
sta $FDDA
ldx #0 ;Clear MSB because I keep seeing
;this done in cc65's source code.
rts ;Return.
.endproc
-------------------------
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