IEC/IRQ related cleanups

c64/kernal/iec_turnaround_to_listen.s

@@ -17,8 +17,6 @@ iec_turnaround_to_listen:
 	bne -
 
 	;; Timeout
-	jsr printf
-	.byte "DBG: TURNAROUND FAILED",$0d,$00
 	sec
 	rts
 

c64/kernal/iec_tx_byte.s

@@ -5,8 +5,8 @@
 
 iec_tx_byte:
 
+	;; Store byte to send on the stack
 	pha
-	php
 
 	;; Notify all devices that we are going to send a byte
 	;; and it is going to be a data byte (released ATN)
@@ -15,7 +15,6 @@ iec_tx_byte:
 	;; Common part of iec_txbyte and iec_tx_common - waits for devices
 	;; and transmits a byte
 
-	plp
 	pla
 	jsr iec_tx_common
 	

c64/kernal/iec_tx_command.s

@@ -3,6 +3,7 @@
 
 iec_tx_command:
 
+	;; Store command to send on the stack
 	pha
 
 	;; Notify all devices that we are going to send a byte
@@ -20,9 +21,6 @@ iec_tx_command:
 	;; No devices present on the bus, so we can immediately return with device not found
 	pla
 
-	jsr printf
-	.byte "DBG: NO DEVICES AT ALL", $0D, 0
-
 	jsr iec_set_idle
 	jmp kernalerror_DEVICE_NOT_FOUND
 *
@@ -47,14 +45,11 @@ iec_tx_command:
 	lda CI2PRA
 	and #BIT_CI2PRA_DAT_IN ; XXX try to optimize this, move to separate routine
 	beq +
-	
+
 	;; XXX possible optimization of the flow above: for many commands it is enough
 	;; to wait for the DATA being pulled, as confirmation is expected from
 	;; a single device only - but not sure if it's worth the trouble
 
-	jsr printf
-	.byte "DBG: NO CONFIRMATION FROM DEVICE", $0D, 0
-
 	jsr iec_set_idle
 	jmp kernalerror_DEVICE_NOT_FOUND
 *

c64/kernal/iec_tx_common.s

@@ -7,16 +7,11 @@ iec_tx_common:
 
 	;; Store the byte to send on a stack
 	pha
-	
-	;; Store the status register - carry flag is used to determine whether
-	;; this is the last byte of the stream
-	php
-	
+
 	;; Wait till all receivers are ready, they should all release DATA
 	jsr iec_wait_for_data_release
 
 	;; At this point a delay 256 usec or more is considered EOI - add waits if necessary
-	plp
 	bcc +
 	jsr iec_wait100us
 	jsr iec_wait100us

c64/kernal/irq_handler.s

@@ -6,7 +6,7 @@ irq_handler:
 	;; $EA61 - Check keyboard, but don't update timer? https://github.com/cc65/cc65/issues/324
 	;; $EA81 - https://www.lemon64.com/forum/viewtopic.php?t=2112&sid=6ea01982b26da69783120a7923ca46fb
 	;; Also the $0314 vector is widely used (e.g., https://www.lemon64.com/forum/viewtopic.php?t=2112&sid=6ea01982b26da69783120a7923ca46fb)
-	
+
 	;; Save registers
 	;; Sequence according to Compute's Mapping the 64 p73
 	pha
@@ -17,7 +17,7 @@ irq_handler:
 
 	;; Call interrupt routine
 	;; (but only if initialised)
-	lda $0314
-	ora $0315
+	lda CINV
+	ora CINV+1
 	beq default_irq_handler
-	jmp ($0314)
+	jmp (CINV)

c64/kernal/open.s

@@ -95,9 +95,6 @@ open_iec:
 	jsr iec_turnaround_to_listen
 	bcs open_iec_error
 
-	jsr printf
-	.byte "DBG: TURNAROUND SUCCEEDED", $0D, 0
-	
 	;; Indicate success
 	lda #$00
 	clc

c64/kernal/vector.s

@@ -61,9 +61,9 @@ vector_restore:
 	;; XXX below we have quite a lot of data... should we decouple them?
 
 vector_defaults:
-	.word $0000    ;; CINV     XXX implement this
-	.word $0000    ;; CBINV    XXX implement this
-	.word $0000    ;; NMINV    XXX implement this
+	.word default_irq_handler    ;; CINV
+	.word $0000                  ;; CBINV    XXX implement this
+	.word $0000                  ;; NMINV    XXX implement this
 	
 	.word open     ;; IOPEN
 	.word close    ;; ICLOSE