+ section "fuq",HOME[$50]
+irqhand:
+ PUSH AF
+ PUSH BC
+ PUSH DE
+ PUSH HL
+
+; ld c, $51
+; ld a, $F0
+; ld [c], a
+
+ xor a
+ ld c, $0F ; ack the irq
+ ld [c], a
+
+ ;ld a, $41 ; print A
+ ;call putc
+
+ ld hl, $DF81
+ ld a, [hl]
+; ld b, 1
+; add b
+ ld c, $51
+; ld [c], a
+; ld [hl], a
+
+
+; ld c, $51
+; ld a, $0F
+; ld [c], a
+
+ POP HL
+ POP DE
+ POP BC
+ POP AF
+ RETI
+
+signon:
+ db $0D,$0A,$1B,"[1mFPGABoy Diagnostic ROM",$1B,"[0m",$0D,$0A,0
+
+; Memory tester: writes h ^ l to all addresses from C000 to DF80.