From ecd4c8934df3e8ea5c2639754c4e00407d21e245 Mon Sep 17 00:00:00 2001
From: OBattler <oubattler@gmail.com>
Date: Wed, 5 Oct 2016 15:41:51 +0200
Subject: [PATCH] Uncompressed sectors from an IMD image now get their actual
 image buffer passed rather than the temporary buffer, fixes writing to IMD
 images; SVGA memory address is now latched with the mask divided by 2 in text
 mode, fixes OS/2 1.1 crashing the emulator.

---
 src/Makefile.mingw |  1 +
 src/disc_imd.c     | 18 ++++++++++++++++--
 src/vid_svga.c     |  9 +++++++--
 3 files changed, 24 insertions(+), 4 deletions(-)

diff --git a/src/Makefile.mingw b/src/Makefile.mingw
index d6a237e0f..55b0910e2 100644
--- a/src/Makefile.mingw
+++ b/src/Makefile.mingw
@@ -31,6 +31,7 @@ LIBS = -mwindows -lwinmm -lopenal.dll -lopenal -lddraw -ldinput8 -ldxguid -ld3d9
 
 86Box.exe: $(OBJ) $(DBOBJ) $(SIDOBJ) $(SLIRPOBJ)
 	$(CC) $(OBJ) $(DBOBJ) $(SIDOBJ) $(SLIRPOBJ) -o "86Box.exe" $(LIBS)
+
 	strip "86Box.exe"
 
 all : 86Box.exe
diff --git a/src/disc_imd.c b/src/disc_imd.c
index 966401309..53bb33d3e 100644
--- a/src/disc_imd.c
+++ b/src/disc_imd.c
@@ -580,9 +580,16 @@ void imd_seek(int drive, int track)
 				id[2] = real_sector;
 				id[3] = (n == 0xFF) ? n_map[actual_sector] : n;
 				ssize = 128 << ((uint32_t) id[3]);
-				data = imd[drive].track_buffer[side] + track_buf_pos[side];
 				type = imd[drive].buffer[imd[drive].tracks[track][side].sector_data_offs[actual_sector]];
 				type = (type >> 1) & 7;
+				if (type & 1)
+				{
+					data = &(imd[drive].buffer[imd[drive].tracks[track][side].sector_data_offs[actual_sector] + 1]);
+				}
+				else
+				{
+					data = imd[drive].track_buffer[side] + track_buf_pos[side];
+				}
 				deleted = bad_crc = 0;
 				if ((type == 2) || (type == 4))  deleted = 1;
 				if ((type == 3) || (type == 4))  bad_crc = 1;
@@ -607,12 +614,19 @@ void imd_seek(int drive, int track)
 				ssize = 128 << ((uint32_t) id[3]);
 				ordered_pos = imd[drive].xdf_ordered_pos[id[2]][side];
 
-				data = imd[drive].track_buffer[side] + track_buf_pos[side];
 				type = imd[drive].buffer[imd[drive].tracks[track][side].sector_data_offs[ordered_pos]];
 				type = (type >> 1) & 7;
 				deleted = bad_crc = 0;
 				if ((type == 2) || (type == 4))  deleted = 1;
 				if ((type == 3) || (type == 4))  bad_crc = 1;
+				if (type & 1)
+				{
+					data = &(imd[drive].buffer[imd[drive].tracks[track][side].sector_data_offs[ordered_pos] + 1]);
+				}
+				else
+				{
+					data = imd[drive].track_buffer[side] + track_buf_pos[side];
+				}
 				imd_sector_to_buffer(drive, track, side, data, ordered_pos, ssize);
 
 				if (is_trackx)
diff --git a/src/vid_svga.c b/src/vid_svga.c
index 9a41776be..4c69bd9e0 100644
--- a/src/vid_svga.c
+++ b/src/vid_svga.c
@@ -587,13 +587,18 @@ void svga_recalctimings(svga_t *svga)
 extern int cyc_total;
 uint32_t svga_mask_addr(uint32_t addr, svga_t *svga)
 {
+	uint32_t limit_shift = 0;
+	if (!(svga->gdcreg[6] & 1))
+	{
+		limit_shift = 1;
+	}
 	if (svga->vrammask == (svga->vram_limit - 1))
 	{
-		return addr % svga->vram_limit;
+		return addr % (svga->vram_limit >> limit_shift);
 	}
 	else
 	{
-		return addr & svga->vrammask;
+		return addr & (svga->vrammask >> limit_shift);
 	}
 }