Millennium II: Fix squished image on MGA modes

Author: Cacodemon345

src/video/vid_mga.c

@@ -736,17 +736,22 @@ mystique_out(uint16_t addr, uint8_t val, void *priv)
         case 0x3df:
             if (mystique->crtcext_idx == 1)
                 svga->dpms = !!(val & 0x30);
+            old = mystique->crtcext_regs[mystique->crtcext_idx];
             if (mystique->crtcext_idx < 6)
                 mystique->crtcext_regs[mystique->crtcext_idx] = val;
+            
+            if (mystique->crtcext_idx == 6 && (old ^ val) == CRTCX_R3_MGAMODE && mystique->type >= MGA_2164W)
+                svga_recalctimings(svga);
 
             if ((mystique->type >= MGA_1064SG) && (mystique->crtcext_idx == 0) &&
                 (mystique->crtcext_regs[3] & CRTCX_R3_MGAMODE)) {
                 svga->rowoffset     = svga->crtc[0x13] |
                                       ((mystique->crtcext_regs[0] & CRTCX_R0_OFFSET_MASK) << 4);
-                svga->rowoffset <<= 1;
+                if (!(mystique->type >= MGA_2164W))                                  
+                    svga->rowoffset <<= 1;
                 svga->ma_latch      = ((mystique->crtcext_regs[0] & CRTCX_R0_STARTADD_MASK) << 16) |
                                       (svga->crtc[0xc] << 8) | svga->crtc[0xd];
-                if (mystique->pci_regs[0x41] & (OPTION_INTERLEAVE >> 8)) {
+                if ((mystique->pci_regs[0x41] & (OPTION_INTERLEAVE >> 8)) && !(mystique->type >= MGA_2164W)) {
                     svga->rowoffset <<= 1;
                     svga->ma_latch <<= 1;
                 }
@@ -935,7 +940,7 @@ mystique_recalctimings(svga_t *svga)
         if (mystique->type >= MGA_1064SG)
             svga->ma_latch      = ((mystique->crtcext_regs[0] & CRTCX_R0_STARTADD_MASK) << 16) | (svga->crtc[0xc] << 8) | svga->crtc[0xd];
 
-        if (mystique->pci_regs[0x41] & (OPTION_INTERLEAVE >> 8)) {
+        if ((mystique->pci_regs[0x41] & (OPTION_INTERLEAVE >> 8)) && !(mystique->type >= MGA_2164W)) {
             svga->rowoffset <<= 1;
             if (mystique->type >= MGA_1064SG)
                 svga->ma_latch <<= 1;
@@ -957,34 +962,55 @@ mystique_recalctimings(svga_t *svga)
                 mystique->ma_latch_old = svga->ma_latch;
             }
 
-            svga->rowoffset <<= 1;
-            switch (mystique->xmulctrl & XMULCTRL_DEPTH_MASK) {
-                case XMULCTRL_DEPTH_8:
-                case XMULCTRL_DEPTH_2G8V16:
-                    svga->render = svga_render_8bpp_highres;
-                    svga->bpp    = 8;
-                    break;
-                case XMULCTRL_DEPTH_15:
-                case XMULCTRL_DEPTH_G16V16:
-                    svga->render = svga_render_15bpp_highres;
-                    svga->bpp    = 15;
-                    break;
-                case XMULCTRL_DEPTH_16:
-                    svga->render = svga_render_16bpp_highres;
-                    svga->bpp    = 16;
-                    break;
-                case XMULCTRL_DEPTH_24:
-                    svga->render = svga_render_24bpp_highres;
-                    svga->bpp    = 24;
-                    break;
-                case XMULCTRL_DEPTH_32:
-                case XMULCTRL_DEPTH_32_OVERLAYED:
-                    svga->render = svga_render_32bpp_highres;
-                    svga->bpp    = 32;
-                    break;
+            if (!(mystique->type >= MGA_2164W))
+                svga->rowoffset <<= 1;
+            if (mystique->type != MGA_2164W) {
+                switch (mystique->xmulctrl & XMULCTRL_DEPTH_MASK) {
+                    case XMULCTRL_DEPTH_8:
+                    case XMULCTRL_DEPTH_2G8V16:
+                        svga->render = svga_render_8bpp_highres;
+                        svga->bpp    = 8;
+                        break;
+                    case XMULCTRL_DEPTH_15:
+                    case XMULCTRL_DEPTH_G16V16:
+                        svga->render = svga_render_15bpp_highres;
+                        svga->bpp    = 15;
+                        break;
+                    case XMULCTRL_DEPTH_16:
+                        svga->render = svga_render_16bpp_highres;
+                        svga->bpp    = 16;
+                        break;
+                    case XMULCTRL_DEPTH_24:
+                        svga->render = svga_render_24bpp_highres;
+                        svga->bpp    = 24;
+                        break;
+                    case XMULCTRL_DEPTH_32:
+                    case XMULCTRL_DEPTH_32_OVERLAYED:
+                        svga->render = svga_render_32bpp_highres;
+                        svga->bpp    = 32;
+                        break;
 
-                default:
-                    break;
+                    default:
+                        break;
+                }
+            } else {
+                switch (svga->bpp) {
+                    case 8:
+                        svga->render = svga_render_8bpp_highres;
+                        break;
+                    case 15:
+                        svga->render = svga_render_15bpp_highres;
+                        break;
+                    case 16:
+                        svga->render = svga_render_16bpp_highres;
+                        break;
+                    case 24:
+                        svga->render = svga_render_24bpp_highres;
+                        break;
+                    case 32:
+                        svga->render = svga_render_32bpp_highres;
+                        break;
+                }
             }
         } else {
             switch (svga->bpp) {