.include "zeropage.inc"
.include "ser-kernel.inc"
.include "ser-error.inc"
- .include "plus4.inc"
+ .include "plus4.inc"
; ------------------------------------------------------------------------
.word PUT
.word STATUS
.word IOCTL
- .word IRQ
+ .word IRQ
;----------------------------------------------------------------------------
; I/O definitions
-ACIA = $DE00
+ACIA = $DE00
ACIA_DATA = ACIA+0 ; Data register
ACIA_STATUS = ACIA+1 ; Status register
ACIA_CMD = ACIA+2 ; Command register
;
.bss
-RecvHead: .res 1 ; Head of receive buffer
-RecvTail: .res 1 ; Tail of receive buffer
-RecvFreeCnt: .res 1 ; Number of bytes in receive buffer
-SendHead: .res 1 ; Head of send buffer
-SendTail: .res 1 ; Tail of send buffer
-SendFreeCnt: .res 1 ; Number of bytes in send buffer
+RecvHead: .res 1 ; Head of receive buffer
+RecvTail: .res 1 ; Tail of receive buffer
+RecvFreeCnt: .res 1 ; Number of bytes in receive buffer
+SendHead: .res 1 ; Head of send buffer
+SendTail: .res 1 ; Tail of send buffer
+SendFreeCnt: .res 1 ; Number of bytes in send buffer
-Stopped: .res 1 ; Flow-stopped flag
-RtsOff: .res 1 ;
+Stopped: .res 1 ; Flow-stopped flag
+RtsOff: .res 1 ;
; Send and receive buffers: 256 bytes each
-RecvBuf: .res 256
-SendBuf: .res 256
+RecvBuf: .res 256
+SendBuf: .res 256
.rodata
; Deactivate DTR and disable 6551 interrupts
- lda #%00001010
- sta ACIA_CMD
+ lda #%00001010
+ sta ACIA_CMD
; Done, return an error code
lda #<SER_ERR_OK
tax ; A is zero
- rts
+ rts
;----------------------------------------------------------------------------
; PARAMS routine. A pointer to a ser_params structure is passed in ptr1.
; Check if the handshake setting is valid
- ldy #SER_PARAMS::HANDSHAKE ; Handshake
+ ldy #SER_PARAMS::HANDSHAKE ; Handshake
lda (ptr1),y
- cmp #SER_HS_HW ; This is all we support
- bne InvParam
+ cmp #SER_HS_HW ; This is all we support
+ bne InvParam
; Initialize buffers
- ldx #0
+ ldx #0
stx Stopped
- stx RecvHead
- stx RecvTail
- stx SendHead
- stx SendTail
+ stx RecvHead
+ stx RecvTail
+ stx SendHead
+ stx SendTail
dex ; X = 255
- stx RecvFreeCnt
- stx SendFreeCnt
+ stx RecvFreeCnt
+ stx SendFreeCnt
; Set the value for the control register, which contains stop bits, word
; length and the baud rate.
lda (ptr1),y ; Baudrate index
tay
lda BaudTable,y ; Get 6551 value
- bmi InvBaud ; Branch if rate not supported
+ bmi InvBaud ; Branch if rate not supported
sta tmp1
- ldy #SER_PARAMS::DATABITS ; Databits
+ ldy #SER_PARAMS::DATABITS ; Databits
lda (ptr1),y
tay
lda BitTable,y
ora tmp1
sta tmp1
- ldy #SER_PARAMS::STOPBITS ; Stopbits
+ ldy #SER_PARAMS::STOPBITS ; Stopbits
lda (ptr1),y
tay
lda StopTable,y
ora tmp1
- ora #%00010000 ; Receiver clock source = baudrate
- sta ACIA_CTRL
+ ora #%00010000 ; Receiver clock source = baudrate
+ sta ACIA_CTRL
; Set the value for the command register. We remember the base value in
; RtsOff, since we will have to manipulate ACIA_CMD often.
- ldy #SER_PARAMS::PARITY ; Parity
+ ldy #SER_PARAMS::PARITY ; Parity
lda (ptr1),y
tay
lda ParityTable,y
- ora #%00000001 ; DTR active
- sta RtsOff
- ora #%00001000 ; Enable receive interrupts
- sta ACIA_CMD
+ ora #%00000001 ; DTR active
+ sta RtsOff
+ ora #%00001000 ; Enable receive interrupts
+ sta ACIA_CMD
; Done
lda #<SER_ERR_OK
tax ; A is zero
- rts
+ rts
; Invalid parameter
InvParam:
- lda #<SER_ERR_INIT_FAILED
- ldx #>SER_ERR_INIT_FAILED
- rts
+ lda #<SER_ERR_INIT_FAILED
+ ldx #>SER_ERR_INIT_FAILED
+ rts
; Baud rate not available
; return.
;
-GET: ldx SendFreeCnt ; Send data if necessary
- inx ; X == $FF?
- beq @L1
- lda #$00
- jsr TryToSend
+GET: ldx SendFreeCnt ; Send data if necessary
+ inx ; X == $FF?
+ beq @L1
+ lda #$00
+ jsr TryToSend
; Check for buffer empty
-@L1: lda RecvFreeCnt ; (25)
- cmp #$ff
- bne @L2
- lda #<SER_ERR_NO_DATA
- ldx #>SER_ERR_NO_DATA
- rts
+@L1: lda RecvFreeCnt ; (25)
+ cmp #$ff
+ bne @L2
+ lda #<SER_ERR_NO_DATA
+ ldx #>SER_ERR_NO_DATA
+ rts
; Check for flow stopped & enough free: release flow control
-@L2: ldx Stopped ; (34)
- beq @L3
- cmp #63
- bcc @L3
- lda #$00
- sta Stopped
- lda RtsOff
- ora #%00001000
- sta ACIA_CMD
+@L2: ldx Stopped ; (34)
+ beq @L3
+ cmp #63
+ bcc @L3
+ lda #$00
+ sta Stopped
+ lda RtsOff
+ ora #%00001000
+ sta ACIA_CMD
; Get byte from buffer
-@L3: ldx RecvHead ; (41)
- lda RecvBuf,x
- inc RecvHead
- inc RecvFreeCnt
- ldx #$00 ; (59)
- sta (ptr1,x)
- txa ; Return code = 0
- rts
+@L3: ldx RecvHead ; (41)
+ lda RecvBuf,x
+ inc RecvHead
+ inc RecvFreeCnt
+ ldx #$00 ; (59)
+ sta (ptr1,x)
+ txa ; Return code = 0
+ rts
;----------------------------------------------------------------------------
; PUT: Output character in A.
; Try to send
- ldx SendFreeCnt
- inx ; X = $ff?
- beq @L2
- pha
- lda #$00
- jsr TryToSend
- pla
+ ldx SendFreeCnt
+ inx ; X = $ff?
+ beq @L2
+ pha
+ lda #$00
+ jsr TryToSend
+ pla
; Put byte into send buffer & send
-@L2: ldx SendFreeCnt
- bne @L3
- lda #<SER_ERR_OVERFLOW ; X is already zero
- rts
-
-@L3: ldx SendTail
- sta SendBuf,x
- inc SendTail
- dec SendFreeCnt
- lda #$ff
- jsr TryToSend
- lda #<SER_ERR_OK
- tax
- rts
+@L2: ldx SendFreeCnt
+ bne @L3
+ lda #<SER_ERR_OVERFLOW ; X is already zero
+ rts
+
+@L3: ldx SendTail
+ sta SendBuf,x
+ inc SendTail
+ dec SendFreeCnt
+ lda #$ff
+ jsr TryToSend
+ lda #<SER_ERR_OK
+ tax
+ rts
;----------------------------------------------------------------------------
; STATUS: Return the status in the variable pointed to by ptr1.
; Must return an error code in a/x.
;
-STATUS: lda ACIA_STATUS
- ldx #0
- sta (ptr1,x)
- txa ; SER_ERR_OK
+STATUS: lda ACIA_STATUS
+ ldx #0
+ sta (ptr1,x)
+ txa ; SER_ERR_OK
rts
;----------------------------------------------------------------------------
IOCTL: lda #<SER_ERR_INV_IOCTL ; We don't support ioclts for now
ldx #>SER_ERR_INV_IOCTL
- rts ; Run into IRQ instead
+ rts ; Run into IRQ instead
;----------------------------------------------------------------------------
; IRQ: Called from the builtin runtime IRQ handler as a subroutine. All
; was handled, otherwise with carry clear.
;
-IRQ: lda ACIA_STATUS ; Check ACIA status for receive interrupt
- and #$08
- beq @L9 ; Jump if no ACIA interrupt (carry still clear)
- lda ACIA_DATA ; Get byte from ACIA
- ldx RecvFreeCnt ; Check if we have free space left
- beq @L1 ; Jump if no space in receive buffer
- ldy RecvTail ; Load buffer pointer
- sta RecvBuf,y ; Store received byte in buffer
- inc RecvTail ; Increment buffer pointer
- dec RecvFreeCnt ; Decrement free space counter
- cpx #33 ; Check for buffer space low
- bcc @L1 ; Assert flow control if buffer space low
+IRQ: lda ACIA_STATUS ; Check ACIA status for receive interrupt
+ and #$08
+ beq @L9 ; Jump if no ACIA interrupt (carry still clear)
+ lda ACIA_DATA ; Get byte from ACIA
+ ldx RecvFreeCnt ; Check if we have free space left
+ beq @L1 ; Jump if no space in receive buffer
+ ldy RecvTail ; Load buffer pointer
+ sta RecvBuf,y ; Store received byte in buffer
+ inc RecvTail ; Increment buffer pointer
+ dec RecvFreeCnt ; Decrement free space counter
+ cpx #33 ; Check for buffer space low
+ bcc @L1 ; Assert flow control if buffer space low
rts ; Return with carry set (interrupt handled)
; Assert flow control if buffer space too low
-@L1: lda RtsOff
- sta ACIA_CMD
- sta Stopped
+@L1: lda RtsOff
+ sta ACIA_CMD
+ sta Stopped
sec ; Interrupt handled
@L9: rts
.proc TryToSend
- sta tmp1 ; Remember tryHard flag
-@L0: lda SendFreeCnt
- cmp #$ff
- beq @L3 ; Bail out
+ sta tmp1 ; Remember tryHard flag
+@L0: lda SendFreeCnt
+ cmp #$ff
+ beq @L3 ; Bail out
; Check for flow stopped
-@L1: lda Stopped
- bne @L3 ; Bail out
+@L1: lda Stopped
+ bne @L3 ; Bail out
; Check that swiftlink is ready to send
-@L2: lda ACIA_STATUS
- and #$10
- bne @L4
- bit tmp1 ;keep trying if must try hard
- bmi @L0
-@L3: rts
+@L2: lda ACIA_STATUS
+ and #$10
+ bne @L4
+ bit tmp1 ;keep trying if must try hard
+ bmi @L0
+@L3: rts
; Send byte and try again
-@L4: ldx SendHead
- lda SendBuf,x
- sta ACIA_DATA
- inc SendHead
- inc SendFreeCnt
- jmp @L0
+@L4: ldx SendHead
+ lda SendBuf,x
+ sta ACIA_DATA
+ inc SendHead
+ inc SendFreeCnt
+ jmp @L0
.endproc
projects / cc65 / blobdiff