From a4bbd19578571724857924e99cdf316580bc67e6 Mon Sep 17 00:00:00 2001
From: Jonathan Campbell <jonathan@castus.tv>
Date: Thu, 13 Jun 2024 23:36:40 -0700
Subject: [PATCH] For ega200 or less than 128KB EGA, just use the CGA 640x200
 2-color mode for splash screen

---
 CHANGELOG         | 3 +++
 src/ints/bios.cpp | 9 ++++++---
 2 files changed, 9 insertions(+), 3 deletions(-)

diff --git a/CHANGELOG b/CHANGELOG
index 7d78712129..654e8b5b1b 100644
--- a/CHANGELOG
+++ b/CHANGELOG
@@ -1,4 +1,7 @@
 Next:
+  - Fix BIOS screen to use CGA 640x200 2-color mode if machine=ega with
+    less than 128KB of video ram, or machine=ega200, instead of showing
+    a garbled 640x350 display. (joncampbell123).
   - Fix memory buffer overrun with machine=ega that can occur with
     640x350 mode and less than 256KB of video RAM. (joncampbell123).
   - The DOSBox clipboard API (via INT 2Fh) is now disabled by default, because
diff --git a/src/ints/bios.cpp b/src/ints/bios.cpp
index fe1ba64ce4..361885d382 100644
--- a/src/ints/bios.cpp
+++ b/src/ints/bios.cpp
@@ -75,6 +75,8 @@ extern bool PS1AudioCard;
 # define S_ISREG(x) ((x & S_IFREG) == S_IFREG)
 #endif
 
+extern bool ega200;
+
 unsigned char ACPI_ENABLE_CMD = 0xA1;
 unsigned char ACPI_DISABLE_CMD = 0xA0;
 unsigned int ACPI_IO_BASE = 0x820;
@@ -10775,9 +10777,10 @@ class BIOS:public Module_base{
             CALLBACK_RunRealInt(0x10);
             DrawDOSBoxLogoVGA((unsigned int)logo_x*8u,(unsigned int)logo_y*(unsigned int)rowheight);
         }
-        else if (machine == MCH_EGA && !textsplash) {
+        else if (machine == MCH_EGA && !textsplash && !ega200 && vga.mem.memsize >= (128*1024)) { /* not ega200 and at least 128KB of VRAM */
             rowheight = 14;
-            reg_eax = 16;       // 640x350 16-color
+            reg_eax = 16; // 640x350 16-color
+
             CALLBACK_RunRealInt(0x10);
 
             // color correction: change Dark Puke Yellow to brown
@@ -10789,7 +10792,7 @@ class BIOS:public Module_base{
 
             DrawDOSBoxLogoVGA((unsigned int)logo_x*8u,(unsigned int)logo_y*(unsigned int)rowheight);
         }
-        else if ((machine == MCH_CGA || machine == MCH_MCGA || machine == MCH_PCJR || machine == MCH_AMSTRAD || machine == MCH_TANDY) && !textsplash) {
+        else if ((machine == MCH_CGA || machine == MCH_EGA || machine == MCH_MCGA || machine == MCH_PCJR || machine == MCH_AMSTRAD || machine == MCH_TANDY) && !textsplash) {
             rowheight = 8;
             reg_eax = 6;        // 640x200 2-color
             CALLBACK_RunRealInt(0x10);