core: clean up SerialIRQPort when uninstalling the interrupt system

Make sure SerialIRQPort is zero when there is no active interrupt
system installed.

Signed-off-by: H. Peter Anvin <hpa@zytor.com>

diff --git a/core/serirq.inc b/core/serirq.inc
index 6babace..b7d79e0 100644 (file)
--- a/core/serirq.inc
+++ b/core/serirq.inc
@@ -190,6 +190,9 @@ sirq_cleanup_nowipe:
                mov cx,8
                rep movsd
 
+               xor ax,ax
+               mov [SerialIRQPort],ax          ; No active interrupt system
+
 .done:
                pop es
                pop ds