Changeset 1070 in vbox

Timestamp:

Feb 27, 2007 9:48:48 AM (18 years ago)

Author:

vboxsync

svn:sync-xref-src-repo-rev:

18947

Message:

Hack up a simple warm boot implementation and use it for int19 reboots
from booted operating systems.

Location:

trunk/src/VBox/Devices/PC

Files:

• BIOS/rombios.c (modified) (5 diffs)
• DevPcBios.cpp (modified) (1 diff)

trunk/src/VBox/Devices/PC/BIOS/rombios.c

@@ -1850 +1850 @@
 {
 #ifdef VBOX
+  // Skip the logo if a warm boot is requested.
+  Bit16u warm_boot = read_word(0x0040,0x0072);
+  write_word(0x0040,0x0072, 0);
+  if (warm_boot == 0x1234)
+    return;
 #ifndef DEBUG
   /* show graphical logo */
@@ -8530 +8535 @@
 ;----------
 int19_relocated: ;; Boot function, relocated
+
+#ifdef VBOX
+  // If an already booted OS calls int 0x19 to reboot, it is not sufficient
+  // just to try booting from the configured drives. All BIOS variables and
+  // interrupt vectors need to be reset, otherwise strange things may happen.
+  // The approach used is faking a warm reboot (which just skips showing the
+  // logo), which is a bit more than what we need, but hey, it's fast.
+  mov bp, sp
+  mov ax, 2[bp]
+  cmp ax, #0xf000
+  jz bios_initiated_boot
+  xor ax, ax
+  mov ds, ax
+  mov ax, #0x1234
+  mov 0x472, ax
+  jmp post
+bios_initiated_boot:
+#endif /* VBOX */
 
   ;; int19 was beginning to be really complex, so now it
@@ -10284 +10307 @@
   mov  ss, ax
 
+#ifndef VBOX
   ;; zero out BIOS data area (40:00..40:ff)
   mov  es, ax
@@ -10291 +10315 @@
   rep
     stosw
+#else /* VBOX */
+  ;; zero out BIOS data area (40:00..40:ff) except word at 40:72
+  mov es, ax
+  mov di, #0x0400
+  cld
+  mov cx, #0x0039 ;; 57 words
+  rep
+    stosw
+  inc di
+  inc di
+  mov cx, #0x0046 ;; 70 words
+  rep
+    stosw
+#endif
 
   call _log_bios_start
@@ -10321 +10359 @@
   ;;   zerod out above
 
+#ifndef VBOX
   ;; Warm Boot Flag 0040:0072
   ;;   value of 1234h = skip memory checks
   ;;   zerod out above
+#endif /* !VBOX */
 
 

trunk/src/VBox/Devices/PC/DevPcBios.cpp

@@ -698 +698 @@
     }
 #endif
+
+    /* Force a BIOS cold boot after a reset. */
+    uint16_t *pu16WarmBoot = (uint16_t *)MMPhysGCPhys2HCVirt(pVM, 0x00000472, 2);
+    AssertRelease(pu16WarmBoot);
+    *pu16WarmBoot = 0;
 }