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call_bios() can now also be called without having paging enabled (it now

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recognizes this and doesn't enable paging after entering the protected
mode again).


git-svn-id: file:///srv/svn/repos/haiku/trunk/current@8135 a95241bf-73f2-0310-859d-f6bbb57e9c96
This commit is contained in:
Axel Dörfler
2004-06-22 23:40:50 +00:00
parent 3ab743efcd
commit a5fb7d4954
1 changed files with 6 additions and 1 deletions
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src/kernel/boot/platform/bios_ia32/bios.S
+6 -1
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@@ -1,6 +1,6 @@
/* /*
** Copyright 2004, Axel Dörfler, axeld@pinc-software.de. All rights reserved. ** Copyright 2004, Axel Dörfler, axeld@pinc-software.de. All rights reserved.
** Distributed under the terms of the OpenBeOS License. ** Distributed under the terms of the Haiku License.
*/ */
@@ -16,6 +16,7 @@
#define REAL_MODE_STACK 0x9000 #define REAL_MODE_STACK 0x9000
// the location of the stack in real mode // the location of the stack in real mode
#define SAVED_ESP 0x10000 #define SAVED_ESP 0x10000
#define SAVED_CR3 0x10004 #define SAVED_CR3 0x10004
#define SAVED_EAX 0x10008 #define SAVED_EAX 0x10008
@@ -56,12 +57,16 @@ _protected_code_segment:
// turn on paging again // turn on paging again
movl SAVED_CR3, %eax // restore the saved page directory movl SAVED_CR3, %eax // restore the saved page directory
orl %eax, %eax // is there a paging directory at all?
jz _no_paging;
movl %eax, %cr3 movl %eax, %cr3
movl %cr0, %eax // set the PG bit (31) to enable paging movl %cr0, %eax // set the PG bit (31) to enable paging
orl $0x80000000, %eax orl $0x80000000, %eax
movl %eax, %cr0 movl %eax, %cr0
_no_paging:
// save the return address so that we can pick it up again later // save the return address so that we can pick it up again later
movl (%esp), %eax movl (%esp), %eax
movl %eax, REAL_MODE_STACK movl %eax, REAL_MODE_STACK