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| author | Paolo Bonzini <pbonzini@redhat.com> | 2015-05-20 17:09:34 +0200 |
|---|---|---|
| committer | Paolo Bonzini <pbonzini@redhat.com> | 2015-05-21 11:44:57 +0200 |
| commit | eaae11e17f022188755c67e4dd3436875e84110d (patch) | |
| tree | 35625017b95776f3eb2470705cb3af2b44687548 /cstart.S | |
| parent | edba90fb16ec7224da591ab8f83efe3673853a3f (diff) | |
| download | qboot-eaae11e17f022188755c67e4dd3436875e84110d.zip qboot-eaae11e17f022188755c67e4dd3436875e84110d.tar.gz qboot-eaae11e17f022188755c67e4dd3436875e84110d.tar.bz2 | |
make a bootable BIOS
includes source from kvm-unit-tests
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'cstart.S')
| -rw-r--r-- | cstart.S | 38 |
1 files changed, 38 insertions, 0 deletions
diff --git a/cstart.S b/cstart.S new file mode 100644 index 0000000..5ca61c8 --- /dev/null +++ b/cstart.S @@ -0,0 +1,38 @@ +.code16gcc +#include "assembly.h" +.section .init +ENTRY(pm_entry) + xor %ax, %ax + mov %ax, %ds + mov %ax, %es + mov %ax, %ss + mov $0x7c00, %sp + + mov %cr0, %eax + or $1, %eax + mov %eax, %cr0 + lgdtl %cs:0xff80 + gdt32_descr - pm_entry + ljmpl $8, $0xffffff80 + 2f - pm_entry +2: + .code32 + mov $16, %ax + mov %ax, %ds + mov %ax, %es + mov %ax, %ss + ljmp $8, $0xffff0000 + +gdt32: + .quad 0 + .quad 0x00cf9b000000ffff // flat 32-bit code segment + .quad 0x00cf93000000ffff // flat 32-bit data segment +gdt32_end: + +gdt32_descr: + .word gdt32_end - gdt32 - 1 + .long 0xffffff80 + gdt32 - pm_entry +ENTRY_END(pm_entry) + + .code16gcc + .section .resetvector + jmp pm_entry + |