From bf52c1172b1441a3e72568b8c6d7288ae5670907 Mon Sep 17 00:00:00 2001
From: TC1995 <mariogplayer90@gmail.com>
Date: Fri, 22 Dec 2023 19:29:42 +0100
Subject: [PATCH 1/2] EGA: Implement PEL panning per hardware features.

---
 src/video/vid_ega.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/src/video/vid_ega.c b/src/video/vid_ega.c
index da77449b0..7cd6c6f17 100644
--- a/src/video/vid_ega.c
+++ b/src/video/vid_ega.c
@@ -108,6 +108,8 @@ ega_out(uint16_t addr, uint8_t val, void *priv)
                     ega_recalctimings(ega);
                 }
             } else {
+                if ((ega->attraddr == 0x13) && (ega->attrregs[0x13] != val))
+                    ega->fullchange = changeframecount;
                 o                                 = ega->attrregs[ega->attraddr & 31];
                 ega->attrregs[ega->attraddr & 31] = val;
                 if (ega->attraddr < 16)

From 524fd30c0c2d1d7e044562ee14e15b8132fa0cb9 Mon Sep 17 00:00:00 2001
From: TC1995 <mariogplayer90@gmail.com>
Date: Fri, 22 Dec 2023 19:43:51 +0100
Subject: [PATCH 2/2] ATI Mach8/32 fixes regarding 1992 ATI Ultra drivers for
 Windows 3.1x: 1. For some reason, background colors were always black under
 those drivers in 8bpp mode, added a tweak to fix it (as well as Clock
 colors). 2. Likewise for the red scrolling in pbrush or write, added a tweak
 to its bitblt read mask. 3. Don't call svga_recalctimings in the hdisp/vdisp
 ports directly, fixes screen size on said drivers without affecting other
 stuff.

---
 src/video/vid_8514a.c     |  8 +++++---
 src/video/vid_ati_mach8.c | 10 +++++++---
 2 files changed, 12 insertions(+), 6 deletions(-)

diff --git a/src/video/vid_8514a.c b/src/video/vid_8514a.c
index 7e476663c..469a4555e 100644
--- a/src/video/vid_8514a.c
+++ b/src/video/vid_8514a.c
@@ -2940,9 +2940,11 @@ rect_fill:
                         } else {
                             while (count-- && dev->accel.sy >= 0) {
                                 if (dev->accel.cx >= dev->accel.clip_left && dev->accel.cx <= clip_r && dev->accel.cy >= dev->accel.clip_top && dev->accel.cy <= clip_b) {
-                                    switch ((mix_dat & mix_mask) ? frgd_mix : bkgd_mix) {
+                                    switch (frgd_mix) {
                                         case 0:
                                             src_dat = bkgd_color;
+                                            if (!bkgd_mix && (dev->accel.cmd & 0x40) && ((dev->accel.frgd_mix & 0x1f) == 7) && ((dev->accel.bkgd_mix & 0x1f) == 3) && !dev->bpp && (bkgd_color == 0x00)) /*For some reason, the September 1992 Mach8/32 drivers for Win3.x don't set the background colors properly.*/
+                                                src_dat = frgd_color;
                                             break;
                                         case 1:
                                             src_dat = frgd_color;
@@ -2962,7 +2964,7 @@ rect_fill:
 
                                     if ((compare_mode == 0) || ((compare_mode == 0x10) && (dest_dat >= compare)) || ((compare_mode == 0x18) && (dest_dat < compare)) || ((compare_mode == 0x20) && (dest_dat != compare)) || ((compare_mode == 0x28) && (dest_dat == compare)) || ((compare_mode == 0x30) && (dest_dat <= compare)) || ((compare_mode == 0x38) && (dest_dat > compare))) {
                                         old_dest_dat = dest_dat;
-                                        MIX(mix_dat & mix_mask, dest_dat, src_dat);
+                                        MIX(1, dest_dat, src_dat);
                                         dest_dat = (dest_dat & wrt_mask) | (old_dest_dat & ~wrt_mask);
                                         WRITE(dev->accel.dest + dev->accel.cx, dest_dat);
                                     }
@@ -3740,7 +3742,7 @@ bitblt:
                                     case 3:
                                         READ(dev->accel.src + dev->accel.cx, src_dat);
                                         if (pixcntl == 3) {
-                                            if (dev->accel.cmd & 0x10) {
+                                            if ((dev->accel.cmd & 0x10) && !(dev->accel.cmd & 0x40)) {
                                                 src_dat = ((src_dat & rd_mask) == rd_mask);
                                             }
                                         }
diff --git a/src/video/vid_ati_mach8.c b/src/video/vid_ati_mach8.c
index 89abde977..5b8dedfbe 100644
--- a/src/video/vid_ati_mach8.c
+++ b/src/video/vid_ati_mach8.c
@@ -3628,7 +3628,9 @@ mach_accel_out(uint16_t port, uint8_t val, mach_t *mach)
         case 0x6e8:
         case 0x6e9:
             if (!(port & 1)) {
-                dev->hdisp = val;
+                if (!dev->on[0] || !dev->on[1])
+                    dev->hdisp = val;
+
                 mach_log("ATI 8514/A: H_DISP write 06E8 = %d\n", dev->hdisp + 1);
             }
             svga_recalctimings(svga);
@@ -3653,8 +3655,10 @@ mach_accel_out(uint16_t port, uint8_t val, mach_t *mach)
 
         case 0x16e8:
         case 0x16e9:
-            WRITE8(port, dev->vdisp, val);
-            dev->vdisp &= 0x1fff;
+            if (!dev->on[0] || !dev->on[1]) {
+                WRITE8(port, dev->vdisp, val);
+                dev->vdisp &= 0x1fff;
+            }
             svga_recalctimings(svga);
             break;