Commit 9f259cc5 authored by H. Peter Anvin's avatar H. Peter Anvin

x86 setup: set %ebx == %ebp == %edi == 0 on protected mode entry

In accordance with the newly formalized 32-bit boot protocol, set
%ebx == %ebp == %edi == 0 in order to support future extensions to the
protocol.
Signed-off-by: default avatarH. Peter Anvin <hpa@zytor.com>
parent 7ed19290
...@@ -28,11 +28,13 @@ ...@@ -28,11 +28,13 @@
* void protected_mode_jump(u32 entrypoint, u32 bootparams); * void protected_mode_jump(u32 entrypoint, u32 bootparams);
*/ */
protected_mode_jump: protected_mode_jump:
xorl %ebx, %ebx # Flag to indicate this is a boot
movl %edx, %esi # Pointer to boot_params table movl %edx, %esi # Pointer to boot_params table
movl %eax, 2f # Patch ljmpl instruction movl %eax, 2f # Patch ljmpl instruction
movw $__BOOT_DS, %cx movw $__BOOT_DS, %cx
xorl %ebx, %ebx # Per the 32-bit boot protocol
xorl %ebp, %ebp # Per the 32-bit boot protocol
xorl %edi, %edi # Per the 32-bit boot protocol
movl %cr0, %edx movl %cr0, %edx
orb $1, %dl # Protected mode (PE) bit orb $1, %dl # Protected mode (PE) bit
......
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