From 1b5ac0f68a7692cb8b3122eb854a791ec3d38afe Mon Sep 17 00:00:00 2001
From: OBattler <oubattler@gmail.com>
Date: Tue, 6 Feb 2024 23:35:43 +0100
Subject: [PATCH] TVP3026: Correctly apply the RAMDAC multiplex mode.

---
 src/video/vid_tvp3026_ramdac.c | 59 ++++++++++++++++++++++++++++++++++
 1 file changed, 59 insertions(+)

diff --git a/src/video/vid_tvp3026_ramdac.c b/src/video/vid_tvp3026_ramdac.c
index a28cc2aed..4b63892de 100644
--- a/src/video/vid_tvp3026_ramdac.c
+++ b/src/video/vid_tvp3026_ramdac.c
@@ -517,6 +517,65 @@ tvp3026_recalctimings(void *priv, svga_t *svga)
     svga->interlace = (ramdac->ccr & 0x40);
     /* TODO: Figure out gamma correction for 15/16 bpp color. */
     svga->lut_map = !!(svga->bpp >= 15 && (ramdac->true_color & 0xf0) != 0x00);
+
+    switch (ramdac->mcr) {
+        case 0x41:
+        case 0x4a:
+        case 0x61:
+            svga->hdisp <<= 1;
+            svga->dots_per_clock <<= 1;
+            break;
+        case 0x42:
+        case 0x4b:
+        case 0x62:
+            svga->hdisp <<= 2;
+            svga->dots_per_clock <<= 2;
+            break;
+        case 0x43:
+        case 0x4c:
+        case 0x63:
+            svga->hdisp <<= 3;
+            svga->dots_per_clock <<= 3;
+            break;
+        case 0x44:
+        case 0x64:
+            svga->hdisp <<= 4;
+            svga->dots_per_clock <<= 4;
+            break;
+        case 0x5b:
+            switch (ramdac->true_color) {
+                case 0x16:
+                case 0x17:
+                    svga->hdisp = (svga->hdisp << 2) / 3;
+                    svga->dots_per_clock = (svga->dots_per_clock << 2) / 3;
+                    break;
+                case 0x1e:
+                case 0x1f:
+                    svga->hdisp = (svga->hdisp * 5) >> 2;
+                    svga->dots_per_clock = (svga->dots_per_clock * 5) >> 2;
+                    break;
+            }
+            break;
+        case 0x5c:
+            switch (ramdac->true_color) {
+                case 0x06:
+                case 0x07:
+                    svga->hdisp <<= 1;
+                    svga->dots_per_clock <<= 1;
+                    break;
+                case 0x16:
+                case 0x17:
+                    svga->hdisp = (svga->hdisp << 3) / 3;
+                    svga->dots_per_clock = (svga->dots_per_clock << 3) / 3;
+                    break;
+                case 0x1e:
+                case 0x1f:
+                    svga->hdisp = (svga->hdisp * 5) >> 1;
+                    svga->dots_per_clock = (svga->dots_per_clock * 5) >> 1;
+                    break;
+            }
+            break;
+    }
 }
 
 uint32_t