Changeset 71422 in vbox for trunk/src/VBox/Devices/PC/BIOS

Timestamp:

Mar 21, 2018 11:20:00 AM (7 years ago)

Author:

vboxsync

Message:

BIOS: INT 15h/87h unconditionally disables A20 gate when done. Also don't just destroy DI register.

File:

• trunk/src/VBox/Devices/PC/BIOS/system.c (modified) (5 diffs)

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

@@ -104 +104 @@
     "call   pentry"                 \
     "pentry:"                       \
-    "pop    di"                     \
-    "add    di, 1Bh"                \
+    "pop    ax"                     \
+    "add    ax, 1Bh"                \
     "push   20h"                    \
-    "push   di"                     \
+    "push   ax"                     \
     "lgdt   fword ptr es:[si+8]"    \
     "lidt   fword ptr cs:pmode_IDT" \
@@ -233 +233 @@
     "cld"                           \
     "rep    movsw"                  \
-    modify nomemory;
+    modify [di] nomemory;
 
 /* The pm_switch has a few crucial differences from pm_enter, hence
@@ -839 +839 @@
 void BIOSCALL int15_blkmove(disk_regs_t r)
 {
-    bx_bool     prev_a20_enable;
     uint16_t    base15_00;
     uint8_t     base23_16;
@@ -850 +849 @@
     int_disable();    /// @todo aren't they disabled already?
 
-    prev_a20_enable = set_enable_a20(1); // enable A20 line
+    set_enable_a20(1);  // enable A20 line
 
     // 128K max of transfer on 386+ ???
@@ -906 +905 @@
     pm_stack_restore();
 
-    set_enable_a20(prev_a20_enable);
+    set_enable_a20(0);  // unconditionally disable A20 line
 
     // turn interrupts back on