From e3345456fa13782e8c41047ca7ce777f3816bdf4 Mon Sep 17 00:00:00 2001
From: Tolik <85737314+Tolik-Trek@users.noreply.github.com>
Date: Fri, 22 May 2026 22:40:15 +1000
Subject: [PATCH] M_INT: RFI is CH-A ONLY (per Z80 SIO spec)

---
 DSS/drivers/Input/MOUSE.ASM | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/DSS/drivers/Input/MOUSE.ASM b/DSS/drivers/Input/MOUSE.ASM
index cb915b2..8c14443 100644
--- a/DSS/drivers/Input/MOUSE.ASM
+++ b/DSS/drivers/Input/MOUSE.ASM
@@ -1008,7 +1008,7 @@ M_INT:	IN	A,(SLOT3)
 	;!TEST SIO INT
 	IF	MOUSE_INT_ENABLED
 	 LD	A,%0011'1000		; return from int
-	 OUT	(Z84.SIO.Ch_B.Ctrl),A
+	 OUT	(Z84.SIO.Ch_A.Ctrl),A	; RFI is CH-A ONLY (per Z80 SIO spec)
 	ENDIF
 	RET