diff options
| author | Andreas Baumann <mail@andreasbaumann.cc> | 2017-06-16 14:50:58 +0200 |
|---|---|---|
| committer | Andreas Baumann <mail@andreasbaumann.cc> | 2017-06-16 14:50:58 +0200 |
| commit | 071a6d2c84d8c8a3557ab038b5795f4401f20838 (patch) | |
| tree | f3dce6c33903b38aebe071b21cd14b883f6d3d44 /src/boot | |
| parent | 7b29f7c528fc647f172ed004f729da29ef7786b9 (diff) | |
| download | abaos-071a6d2c84d8c8a3557ab038b5795f4401f20838.tar.gz abaos-071a6d2c84d8c8a3557ab038b5795f4401f20838.tar.bz2 | |
fixed the stack position to 0x2000, not 0xFFFF in real mode!
zeroing all general purpose registers after switching to protected mode
Diffstat (limited to 'src/boot')
| -rw-r--r-- | src/boot/boot.asm | 14 |
1 files changed, 12 insertions, 2 deletions
diff --git a/src/boot/boot.asm b/src/boot/boot.asm index 75ad05e..0f31c9d 100644 --- a/src/boot/boot.asm +++ b/src/boot/boot.asm @@ -22,8 +22,11 @@ ; make sure we know the location of the stack by setting it on our own ; this stack is only used in real mode in stage 1, so it's growing from -; 0xffff down - mov bp, 0xFFFF +; 0x2000 down, we should really not set it above 0x7c00, as this is +; exacly the place, where we load stage 2 and the kernel to! (was 0xffff, +; which was a really bad idea after the kernel got bigger than roughly +; 32k!) + mov bp, 0x2000 mov sp, bp ; print out some information about CPU mode and BIOS boot drive @@ -170,6 +173,13 @@ MESSAGE_HALTED_REAL: [bits 32] BEGIN_PROTECTED_MODE: +; make sure registers have known values + xor eax, eax + xor ebx, ebx + xor ecx, ecx + xor edx, edx + xor esi, esi + xor edi, edi ; we switched to protected mode mov si, MESSAGE_PROTECTED_MODE |