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Carry is clear on IRQ entry

git-svn-id: svn://svn.cc65.org/cc65/trunk@3500 b7a2c559-68d2-44c3-8de9-860c34a00d81
This commit is contained in:
cuz 2005-05-05 10:11:23 +00:00
parent 3c4cd1fff9
commit f096dc95ae
3 changed files with 27 additions and 43 deletions

View File

@ -344,8 +344,9 @@ IOCTL: lda #<SER_ERR_INV_IOCTL ; We don't support ioclts for now
;----------------------------------------------------------------------------
; IRQ: Called from the builtin runtime IRQ handler as a subroutine. All
; registers are already save, no parameters are passed and no return code
; is expected.
; registers are already save, no parameters are passed, but the carry flag
; is clear on entry. The routine must return with carry set if the interrupt
; was handled, otherwise with carry clear.
;
IRQ: lda #$0F
@ -353,16 +354,16 @@ IRQ: lda #$0F
ldy #ACIA::STATUS
lda (acia),y ; Check ACIA status for receive interrupt
and #$08
beq @L10 ; Jump if no ACIA interrupt
beq @L9 ; Jump if no ACIA interrupt (carry still clear)
ldy #ACIA::DATA
lda (acia),y ; Get byte from ACIA
ldx RecvFreeCnt ; Check if we have free space left
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
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
bcs @L9 ; Assert flow control if buffer space low
; Assert flow control if buffer space too low
@ -370,7 +371,7 @@ IRQ: lda #$0F
@L1: lda RtsOff
ldy #ACIA::CMD
sta (acia),y
sta Stopped
sta Stopped
sec ; Interrupt handled
; Done, switch back to the execution segment
@ -379,13 +380,6 @@ IRQ: lda #$0F
sta IndReg
rts
; No ACIA interrupt
@L10: clc ; Interrupt not handled
lda ExecReg
sta IndReg
rts
;----------------------------------------------------------------------------
; Try to send a byte. Internal routine. A = TryHard

View File

@ -344,8 +344,9 @@ IOCTL: lda #<SER_ERR_INV_IOCTL ; We don't support ioclts for now
;----------------------------------------------------------------------------
; IRQ: Called from the builtin runtime IRQ handler as a subroutine. All
; registers are already save, no parameters are passed and no return code
; is expected.
; registers are already save, no parameters are passed, but the carry flag
; is clear on entry. The routine must return with carry set if the interrupt
; was handled, otherwise with carry clear.
;
IRQ: lda #$0F
@ -353,16 +354,16 @@ IRQ: lda #$0F
ldy #ACIA::STATUS
lda (acia),y ; Check ACIA status for receive interrupt
and #$08
beq @L10 ; Jump if no ACIA interrupt
beq @L9 ; Jump if no ACIA interrupt (carry still clear)
ldy #ACIA::DATA
lda (acia),y ; Get byte from ACIA
ldx RecvFreeCnt ; Check if we have free space left
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
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
bcs @L9 ; Assert flow control if buffer space low
; Assert flow control if buffer space too low
@ -370,7 +371,7 @@ IRQ: lda #$0F
@L1: lda RtsOff
ldy #ACIA::CMD
sta (acia),y
sta Stopped
sta Stopped
sec ; Interrupt handled
; Done, switch back to the execution segment
@ -379,13 +380,6 @@ IRQ: lda #$0F
sta IndReg
rts
; No ACIA interrupt
@L10: clc ; Interrupt not handled
lda ExecReg
sta IndReg
rts
;----------------------------------------------------------------------------
; Try to send a byte. Internal routine. A = TryHard

View File

@ -346,13 +346,14 @@ IOCTL: lda #<SER_ERR_INV_IOCTL ; We don't support ioclts for now
;----------------------------------------------------------------------------
; IRQ: Called from the builtin runtime IRQ handler as a subroutine. All
; registers are already save, no parameters are passed and no return code
; is expected.
; registers are already save, no parameters are passed, but the carry flag
; is clear on entry. The routine must return with carry set if the interrupt
; was handled, otherwise with carry clear.
;
IRQ: lda ACIA_STATUS ; Check ACIA status for receive interrupt
and #$08
beq @L10 ; Jump if no ACIA interrupt
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
@ -370,12 +371,7 @@ IRQ: lda ACIA_STATUS ; Check ACIA status for receive interrupt
sta ACIA_CMD
sta Stopped
sec ; Interrupt handled
rts
; No ACIA interrupt
@L10: clc ; Interrupt not handled
rts
@L9: rts
;----------------------------------------------------------------------------
; Try to send a byte. Internal routine. A = TryHard