metal-cos/sys/amd64/multiboot.S
2014-02-12 13:47:13 -08:00

118 lines
2.3 KiB
ArmAsm

/*
* Multiboot Entry
*/
#define STACK_SIZE 0x4000
#define MULTIBOOT_HEADER_MAGIC 0x1BADB002
#define MULTIBOOT_HEADER_FLAGS 0x00010003
.extern mb_entry
.text
.globl _start
_start: .code32
jmp multiboot_entry
.align 4
multiboot_header: .code32
.long MULTIBOOT_HEADER_MAGIC
.long MULTIBOOT_HEADER_FLAGS
.long -(MULTIBOOT_HEADER_MAGIC + MULTIBOOT_HEADER_FLAGS)
.long multiboot_header
.long _start
.long _edata
.long _end
.long multiboot_entry
//
// Multiboot entry
// %eax: Magic (0x2BADB002)
// %ebx: multiboot info structure
//
multiboot_entry: .code32
movl %eax, %edx // Save multiboot magic
movl $(lmfarptr), %edi
movw $(0x7000 + 'A'), (0xB8000)
movl $(stack + STACK_SIZE), %esp
movw $(0x7000 + 'B'), (0xB8002)
pushl $0
popf
movw $(0x7000 + 'C'), (0xB8004)
movl %cr4, %eax
orl $0x0000006A0, %eax
movl %eax, %cr4
movw $(0x7000 + 'D'), (0xB8006)
movl $bootpgtbl1, %eax
movl %eax, %cr3
movw $(0x7000 + 'E'), (0xB8008)
movl $0xC0000080, %ecx
rdmsr
orl $0x0900, %eax
wrmsr
movw $(0x7000 + 'E'), (0xB800A)
movl $bootgdtdesc, %eax
lgdt (%eax)
movw $(0x7000 + 'F'), (0xB800C)
movl %cr0, %eax
orl $0x8005002B, %eax
movl %eax, %cr0
movw $(0x7000 + '0'), (0xB800E)
ljmp *(%edi)
lmenter: .code64
movw $(0x7000 + '1'), (0xB8010)
movw $0x10, %ax
movw %ax, %ss
movw %ax, %ds
movw %ax, %es
movw %ax, %fs
movw %ax, %gs
movw $(0x7000 + '2'), (0xB8012)
movq %rdx, %rdi // Magic
movq %rbx, %rsi // Multiboot info pointer
call mb_entry
movw $(0x5000 + 'H'), (0xB8098)
movw $(0x5000 + 'A'), (0xB809A)
movw $(0x5000 + 'L'), (0xB809C)
movw $(0x5000 + 'T'), (0xB809E)
loop:
hlt
jmp loop
lmfarptr:
.long lmenter
.word 0x08
.p2align 12
bootgdt:
.quad 0x0000000000000000 /* Null */
.quad 0x00AF9A000000FFFF /* Kernel CS */
.quad 0x00CF92000000FFFF /* Kernel DS */
.quad 0x0000000000000000
.quad 0x0000000000000000
.quad 0x0000000000000000
.quad 0x0000000000000000
.p2align 4
bootgdtdesc:
.word 0x0040
.quad bootgdt
// Boot stack
.comm stack, STACK_SIZE