further IO stack refactoring

c64/kernal/f333.clrchn.jmp.s

@@ -1,6 +0,0 @@
-
-// Our implementation is longer than the original one,
-// placing it here would cause a collision with OPEN
-
-CLRCHN:
-    jmp clrchn_real

c64/kernal/iec/ciout.s

@@ -11,6 +11,8 @@
 
 CIOUT:
 
+#if CONFIG_IEC
+
 	pha
 	lda C3PO
 	bne ciout_send_byte
@@ -35,3 +37,9 @@ ciout_send_byte:
 	inc C3PO // iec_tx_byte sets it to 0, but we still have something to send
 	jmp ciout_store_in_buffer
 
+#else
+
+	sec // indicate failure
+	rts
+
+#endif

c64/kernal/iec/clrchn_iec.s

@@ -0,0 +1,30 @@
+
+//
+// IEC part of the CLRCHN routine
+//
+
+
+#if CONFIG_IEC
+
+
+clrchn_iec:
+
+	// Check input device
+	lda DFLTN
+	jsr iec_check_devnum_oc
+	bcs !+
+
+	// It was IEC device - send UNTALK first
+	jsr UNTLK
+!:
+	// Check output device
+	lda DFLTO
+	jsr iec_check_devnum_oc
+
+	// If it was IEC device - send UNLSN first
+	bcc_far UNLSN
+
+	rts
+
+
+#endif // CONFIG_IEC

c64/kernal/iostack/f333.clrchn.s

@@ -9,26 +9,22 @@
 //
 
 
-clrchn_real:
+CLRCHN:
+
+#if CONFIG_IEC
+	jsr clrchn_iec
+#else
+	nop // just to prevent double label
+#endif
+
+	// FALLTROUGH
 
-	// Handle IEC input device
-	lda DFLTN
-	jsr iec_check_devnum_oc
-	bcs !+
-	// Previous device was IEC one - send UNTALK first
-	jsr UNTLK
-!:
-	// Restore output device to default
-	lda DFLTO
-	jsr iec_check_devnum_oc
-	bcs !+
-	// Handle IEC output device
-	jsr UNLSN
-!:
 clrchn_reset: // entry needed by setup_vicii
+
 	// Set input device number to keyboard
 	lda #$00
 	sta DFLTN
+
 	// Set output device number to screen
 	lda #$03
 	sta DFLTO

c64/kernal/keyboard/udtim_keyboard.s

@@ -1,29 +1,12 @@
 
 //
-// Official Kernal routine, described in:
-//
-// - [RG64] C64 Programmer's Reference Guide   - page 303
-// - [CM64] Compute's Mapping the Commodore 64 - pages 27, 232
-//
-// CPU registers that has to be preserved (see [RG64]): .Y
+// Keyboard part of the UDTIM routine, has to preserve .Y
 //
 
-UDTIM:
 
-	// Update jiffy clock. The whole day is $4F1A00 jiffies (24 hours * 60 minutes * 60 seconds * 60 jiffies),
-	// after this time we have to reset the clock.
+udtim_keyboard:
 
-	inc TIME+0
-	bne udtim_update_stkey   // done with clock
-	inc TIME+1
-	bne udtim_clock_rollover
-	inc TIME+2
-
-	// FALLTROUGH
-
-udtim_update_stkey: // entry to be used when interrupts are disabled
-
-	// According to [CM64], page 27, another action we have to perform is to copy
+	// According to [CM64], page 27, the action we have to perform is to copy
 	// the last row of keyboard to RAM, so that various routines can detect the STOP
 	// key press. But something as simple as this would have created warm restart
 	// with M+N+SPACE+RESTORE due to ghosting - so the original ROM has to provide
@@ -65,17 +48,3 @@ udtim_update_stkey: // entry to be used when interrupts are disabled
 	// unable to, for example, read the space bar status.
 
 	rts
-
-udtim_clock_rollover:
-
-	// At this point TIME+0 contains 0
-	lda TIME+1
-	cmp #$1A
-	bne udtim_update_stkey   // done with clock
-	lda TIME+2
-	cmp #$4F
-	bne udtim_update_stkey   // done with clock
-	lda #$00
-	sta TIME+2
-	sta TIME+1
-	beq udtim_update_stkey   // done with clock - will always jump

c64/kernal/time/udtim.s

@@ -0,0 +1,41 @@
+
+//
+// Official Kernal routine, described in:
+//
+// - [RG64] C64 Programmer's Reference Guide   - page 303
+// - [CM64] Compute's Mapping the Commodore 64 - pages 27, 232
+//
+// CPU registers that has to be preserved (see [RG64]): .Y
+//
+
+UDTIM:
+
+	// Update jiffy clock. The whole day is $4F1A00 jiffies
+	// (24 hours * 60 minutes * 60 seconds * 60 jiffies),
+	// after this time we have to reset the clock.
+
+	inc TIME+0
+	bne udtim_time_done   // done with clock
+	inc TIME+1
+	bne udtim_clock_rollover
+	inc TIME+2
+
+	// FALLTROUGH
+
+udtim_time_done:
+
+	jmp udtim_keyboard
+
+udtim_clock_rollover:
+
+	// At this point TIME+0 contains 0
+	lda TIME+1
+	cmp #$1A
+	bne udtim_time_done   // done with clock
+	lda TIME+2
+	cmp #$4F
+	bne udtim_time_done   // done with clock
+	lda #$00
+	sta TIME+2
+	sta TIME+1
+	beq udtim_time_done   // done with clock - will always jump