From 89c9f7d9ad54efd4cf7ff34a11018346639ab785 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Sebastian=20Strohh=C3=A4cker?=
 <c2woody@users.sourceforge.net>
Date: Mon, 28 May 2007 16:29:11 +0000
Subject: [PATCH] fix reading vga sequencer data port for invalid indices,
 thanks to vasyl (see sf bug #1173098); fixes some svga detection routines
 (Grandest Fleet 2, sf bug #1723717)

Imported-from: https://svn.code.sf.net/p/dosbox/code-0/dosbox/trunk@2861
---
 src/hardware/vga_s3.cpp  | 7 ++++++-
 src/hardware/vga_seq.cpp | 2 --
 2 files changed, 6 insertions(+), 3 deletions(-)

diff --git a/src/hardware/vga_s3.cpp b/src/hardware/vga_s3.cpp
index 7bdc3c09..ec418544 100644
--- a/src/hardware/vga_s3.cpp
+++ b/src/hardware/vga_s3.cpp
@@ -16,7 +16,7 @@
  *  Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  */
 
-/* $Id: vga_s3.cpp,v 1.6 2007-01-08 19:45:40 qbix79 Exp $ */
+/* $Id: vga_s3.cpp,v 1.7 2007-05-28 16:29:11 c2woody Exp $ */
 
 #include "dosbox.h"
 #include "inout.h"
@@ -375,6 +375,7 @@ Bitu SVGA_S3_ReadCRTC( Bitu reg, Bitu iolen) {
 }
 
 void SVGA_S3_WriteSEQ(Bitu reg,Bitu val,Bitu iolen) {
+	if (reg>0x8 && vga.s3.pll.lock!=0x6) return;
 	switch (reg) {
 	case 0x08:
 		vga.s3.pll.lock=val;
@@ -405,6 +406,10 @@ void SVGA_S3_WriteSEQ(Bitu reg,Bitu val,Bitu iolen) {
 
 Bitu SVGA_S3_ReadSEQ(Bitu reg,Bitu iolen) {
 	/* S3 specific group */
+	if (reg>0x8 && vga.s3.pll.lock!=0x6) {
+		if (reg<0x1b) return 0;
+		else return reg;
+	}
 	switch (reg) {
 	case 0x08:		/* PLL Unlock */
 		return vga.s3.pll.lock;
diff --git a/src/hardware/vga_seq.cpp b/src/hardware/vga_seq.cpp
index 6ca66344..04d29aa6 100644
--- a/src/hardware/vga_seq.cpp
+++ b/src/hardware/vga_seq.cpp
@@ -31,7 +31,6 @@ void write_p3c4(Bitu port,Bitu val,Bitu iolen) {
 };
 
 void write_p3c5(Bitu port,Bitu val,Bitu iolen) {
-	if (seq(index)>0x8 && vga.s3.pll.lock!=0x6) return;
 //	LOG_MSG("SEQ WRITE reg %X val %X",seq(index),val);
 	switch(seq(index)) {
 	case 0:		/* Reset */
@@ -114,7 +113,6 @@ void write_p3c5(Bitu port,Bitu val,Bitu iolen) {
 
 Bitu read_p3c5(Bitu port,Bitu iolen) {
 //	LOG_MSG("VGA:SEQ:Read from index %2X",seq(index));
-	if (seq(index)>0x8 && vga.s3.pll.lock!=0x6) return seq(index);
 	switch(seq(index)) {
 	case 0:			/* Reset */
 		return seq(reset);