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Apple2 SSC: Implement no flow control

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This commit is contained in:
Colin Leroy-Mira 2023-10-27 07:07:38 +02:00 committed by Oliver Schmidt
parent 5b47def166
commit 94239525ca
1 changed files with 11 additions and 5 deletions
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16
libsrc/apple2/ser/a2.ssc.s
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@ -87,6 +87,7 @@ SendFreeCnt: .res 1 ; Number of free bytes in send buffer
Stopped: .res 1 ; Flow-stopped flag
RtsOff: .res 1 ; Cached value of command register with
; flow stopped
HSType: .res 1 ; Flow-control type
RecvBuf: .res 256 ; Receive buffer: 256 bytes
SendBuf: .res 256 ; Send buffer: 256 bytes
@ -276,13 +277,15 @@ NoDev: lda #SER_ERR_NO_DEVICE
; Check if the handshake setting is valid
AciaOK: ldy #SER_PARAMS::HANDSHAKE
lda (ptr1),y
cmp #SER_HS_HW ; This is all we support
beq HandshakeOK
cmp #SER_HS_SW ; Not supported
bne HandshakeOK
lda #SER_ERR_INIT_FAILED
bne Out
HandshakeOK:
sta HSType ; Store flow control type
ldy #$00 ; Initialize buffers
sty Stopped
sty RecvHead
@ -473,11 +476,14 @@ SER_IRQ:
bcc Flow ; Assert flow control if buffer space low
rts ; Interrupt handled (carry already set)
Flow: ldx Index ; Assert flow control if buffer space too low
lda RtsOff
Flow: lda HSType ; Don't touch if no flow control
beq IRQDone
ldx Index ; Assert flow control if buffer space too low
lda RtsOff
sta ACIA_CMD,x
sta Stopped
sec ; Interrupt handled
IRQDone:sec ; Interrupt handled
Done: rts
;----------------------------------------------------------------------------