STOP + RESTORE now works (bad news: works even without STOP)

c64/kernal/interrupts/ea31.default_irq_handler.s

@@ -2,7 +2,8 @@
 default_irq_handler:	
 
 	jsr blink_cursor
-	jsr scan_keyboard
+	jsr JSCNKEY
+	jsr JUDTIM ; update jiffy clock
 
 	;; Acknowledge CIA interrupt and return
 	jmp clear_cia1_interrupt_flag_and_return_from_interrupt

c64/kernal/interrupts/fe47.default_nmi_handler.s

@@ -1,12 +1,25 @@
 
 default_nmi_handler:
 
-	;; XXX implement according to Compute's Mapping the Commodore 64, page 74
+	;; Implemented according to Compute's Mapping the Commodore 64, page 74
+	;; and to https://www.c64-wiki.com/wiki/Interrupt
+
+	;; Save registers, sequence according to Compute's Mapping the Commodore 64, page 73
+	pha
+	txa
+	pha
+	tya
+	pha
+
+	;; XXX: RS-232 support is not implemented
 
-	;; XXX check if the source was RESTORE key, quit if it wasn't (no RS-232 support)
 	;; XXX if cartridge present, enter it through warm start vector
-	;; XXX if stop pressed, go to default_brk_handler
 
-	inc $D020
-	rti
+	;; According to C64 Wiki, if STOP key is pressed, the routine assumes warm start request
+
+	jsr JSTOP
+	bcs +
+	jmp return_from_interrupt ; no STOP pressed
+*
+	jmp (CBINV) ; STOP + RESTORE
 

c64/kernal/interrupts/fe66.default_brk_handler.s

@@ -3,9 +3,13 @@ default_brk_handler:
 
 	;; Implemented according to Compute's Mapping the Commodore 64, pages 73-74
 
+	sei ; disable IRQs, to be sure they won't interfere
+
 	jsr JRESTOR
 	jsr JIOINIT
 	jsr CINT_BRK
 
+	cli
+
 	jmp (IBASIC_WARM_START)
 

c64/kernal/interrupts/irq_handler.s

@@ -15,6 +15,8 @@ irq_handler:
 	tya
 	pha
 
+	;; XXX check if caused by BRK, react accordingly
+
 	;; Call interrupt routine (only if initialised)
 	lda CINV
 	ora CINV+1

c64/kernal/interrupts/nmi_handler.s

@@ -1,7 +1,18 @@
 
 nmi_handler:
 
-	;; XXX provide real implementation
+	sei ;; don't allow IRQ to interfere, see https://www.c64-wiki.com/wiki/Interrupt
 
+	;; Call interrupt routine (only if initialised)
+	pha
+	lda NMINV
+	ora NMINV+1
+	bne +
+	pla
 	jmp (NMINV)
+*
+	;; Vector not initialized - call default interrupt routine
+	pla
+	jmp default_nmi_handler
+