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Fix ACIA check so we don't enable RX/TX with IRQs on

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Colin Leroy-Mira 2023-10-15 15:26:58 +02:00 committed by Oliver Schmidt
parent 3107f34ec9
commit 882f6fd103
1 changed files with 14 additions and 23 deletions
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37
libsrc/apple2/ser/a2.ssc.s
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@ -252,32 +252,23 @@ NotIIgs:ldx #<$C000
lda ACIA_CMD,x ; and command register. So we can restore them
sta tmp2 ; if this isn't a 6551.
and #%11111110
sta ACIA_CMD,x ; Disable receiver/transmitter
lda ACIA_CMD,x ; Reload register
and #%00000001
bne NotAcia ; We expect command register bit 0 to be 0
lda tmp2
ora #%00000001 ; Enable receiver/transmitter
ldy #%00000010 ; Disable TX/RX, disable IRQ
: tya
sta ACIA_CMD,x
sta tmp3 ; Store it for comparison
lda ACIA_CMD,x ; Is command register what we wrote?
cmp tmp3
cmp ACIA_CMD,x ; Verify what we stored is there
bne NotAcia
iny ; Enable TX/RX, disable IRQ
cpy #%00000100
bne :-
sta ACIA_STATUS,x ; Reset ACIA
lda ACIA_CMD,x ; Check that RX/TX is disabled
lsr
bcc AciaOK
sta ACIA_STATUS,x ; Reset Acia (value written is not important)
lda ACIA_CMD,x ; Is the Acia disabled now?
and #%00000001
beq AciaOK
NotAcia:lda tmp2 ; Restore original values
sta ACIA_CMD,x
lda tmp1
sta ACIA_STATUS,x
NotAcia:lda tmp2 ; Restore original values
sta ACIA_CMD,x
lda tmp1
sta ACIA_STATUS,x
NoDev: lda #SER_ERR_NO_DEVICE
bne Out