From c9e35f37217f25f1f576754df464a8ec0d6d22fe Mon Sep 17 00:00:00 2001
From: "H. Peter Anvin" <hpa@zytor.com>
Date: Tue, 12 Feb 2008 15:48:25 -0800
Subject: [PATCH] getc: don't clobber AH; return CF=1, AL=0 on end of file

Don't clobber AH when calling getc; when returning with CF=1 (EOF),
always return with AL=0.
---
 getc.inc | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/getc.inc b/getc.inc
index 4a9d243..275c0fa 100644
--- a/getc.inc
+++ b/getc.inc
@@ -100,8 +100,9 @@ getc:
 		and bx,bx
 		jnz .have_unget
 
-		mov ax,real_mode_seg	; Borrow the real_mode_seg
-		mov es,ax
+		mov si,real_mode_seg	; Borrow the real_mode_seg
+		mov es,si
+
 .got_data:
 		sub word [di+gc_bufbytes],1
 		jc .get_data		; Was it zero already?
@@ -154,6 +155,7 @@ getc:
 		; to read the file.
 		mov [di+gc_bufbytes],cx
 		popad
+		xor al,al		; Return a predictable zero
 		stc
 		jmp .ret
 
-- 
2.7.4