Alex Henrie : krnl386: Emulate the VGA status register.

[Alexandre Julliard]

Module: wine
Branch: master
Commit: b87bd5e9b0f9536e78254c877bd333d46d151509
URL:    https://gitlab.winehq.org/wine/wine/-/commit/b87bd5e9b0f9536e78254c877bd333d...

Author: Alex Henrie 
Date:   Sun Jan 28 00:16:14 2024 -0700

krnl386: Emulate the VGA status register.

Sega Bug uses it as a timer.

---

dlls/krnl386.exe16/ioports.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/dlls/krnl386.exe16/ioports.c b/dlls/krnl386.exe16/ioports.c
index 7f795c2badf..dc188fabecf 100644
--- a/dlls/krnl386.exe16/ioports.c
+++ b/dlls/krnl386.exe16/ioports.c
@@ -316,6 +316,9 @@ DWORD DOSVM_inport( int port, int size )
     case 0x201:
         res = ~0U; /* no joystick */
         break;
+    case 0x3da:
+        res = GetTickCount() % 17 == 0 ? 0x4 : 0; /* report vblank about 60 times per second */
+        break;
     default:
         WARN("Direct I/O read attempted from port %x\n", port);
         break;