From 0c49f05afe84f23c361a05f2890b966af21536bb Mon Sep 17 00:00:00 2001
From: Robert Pengelly <robertapengelly@hotmail.com>
Date: Sun, 18 Oct 2026 12:30:45 +0100
Subject: [PATCH] Implement BIOS cursor visibility control and restore on exit

---
 interrupts.c |  7 +++++++
 main.c       | 16 ++++++++++++++++
 2 files changed, 23 insertions(+)

diff --git a/interrupts.c b/interrupts.c
index 5c8edd5..4502012 100644
--- a/interrupts.c
+++ b/interrupts.c
@@ -6044,6 +6044,10 @@ static void bios_video_initialize (void) {
     }
 
     bios_video_initialized = 1;
+    
+    /* The BIOS text screen starts blank; remove any previous host output. */
+    fputs ("\033[2J\033[H", stdout);
+    fflush (stdout);
 
 }
 
@@ -6087,6 +6091,9 @@ static void int_10 (CPU8086 *cpu) {
             bios_cursor_start = (uint8_t) (cpu->regs[REG_CX] >> 8);
             bios_cursor_end = (uint8_t) cpu->regs[REG_CX];
             
+            fputs ((bios_cursor_start & 0x20) ? "\033[?25l" : "\033[?25h", stdout);
+            fflush (stdout);
+            
             break;
         
         case 0x02: {                    /* set cursor position */
diff --git a/main.c b/main.c
index 14d9a34..d27e696 100644
--- a/main.c
+++ b/main.c
@@ -15,6 +15,13 @@
 #define     MEM_SIZE                    (640UL << 10)
 #define     EXE_LOAD_SEG                0x0060
 
+static void restore_terminal_cursor (void) {
+
+    fputs ("\033[?25h", stdout);
+    fflush (stdout);
+
+}
+
 static void usage (const char *argv0) {
     fprintf (stderr, "Usage: %s [--trace] program.com\n", argv0);
 }
@@ -270,6 +277,15 @@ int main (int argc, char **argv) {
     
     }
     
+    if (atexit (restore_terminal_cursor) != 0) {
+    
+        fprintf (stderr, "Failed to register terminal cursor cleanup\n");
+        
+        free (mem);
+        return 1;
+    
+    }
+    
     /* init_dos_heap(&cpu, 0x2000); */
     init_ivt (&cpu);
     
-- 
2.34.1