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Apple 2 SSC: Handle SER_HS_NONE with no performance impact

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This commit is contained in:
Colin Leroy-Mira 2023-11-03 07:50:28 +01:00
parent b7f4a9a93e
commit 0eafb6d1d5
1 changed files with 8 additions and 8 deletions
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16
libsrc/apple2/ser/a2.ssc.s
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@ -87,7 +87,6 @@ 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
@ -284,7 +283,7 @@ AciaOK: ldy #SER_PARAMS::HANDSHAKE
bne Out
HandshakeOK:
sta HSType ; Store flow control type
sta tmp2 ; Store flow control type
ldy #$00 ; Initialize buffers
sty Stopped
@ -335,8 +334,12 @@ BaudOK: sta tmp1
ora #%00001000 ; Enable receive interrupts (RTS low)
sta ACIA_CMD,x
ldy tmp2 ; Check flow control type
bne Opened
sta RtsOff ; Disable flow control if required
; Done
stx Index ; Mark port as open
Opened: stx Index ; Mark port as open
lda #SER_ERR_OK
Out:
ldx #$00 ; Promote char return value
@ -476,14 +479,11 @@ SER_IRQ:
bcc Flow ; Assert flow control if buffer space low
rts ; Interrupt handled (carry already set)
Flow: lda HSType ; Don't touch if no flow control
beq IRQDone
ldx Index ; Assert flow control if buffer space too low
Flow: ldx Index ; Assert flow control if buffer space too low
lda RtsOff
sta ACIA_CMD,x
sta Stopped
IRQDone:sec ; Interrupt handled
sec ; Interrupt handled
Done: rts
;----------------------------------------------------------------------------