149 lines
3.9 KiB
NASM
149 lines
3.9 KiB
NASM
%include "startup-common.asm"
|
|
|
|
startup_arch:
|
|
; load protected mode GDT and IDT
|
|
cli
|
|
lgdt [gdtr]
|
|
lidt [idtr]
|
|
; set protected mode bit of cr0
|
|
mov eax, cr0
|
|
or eax, 1
|
|
mov cr0, eax
|
|
|
|
; far jump to load CS with 32 bit segment
|
|
jmp gdt.kernel_code:protected_mode
|
|
|
|
USE32
|
|
protected_mode:
|
|
; load all the other segments with 32 bit data segments
|
|
mov eax, gdt.kernel_data
|
|
mov ds, eax
|
|
mov es, eax
|
|
mov fs, eax
|
|
mov gs, eax
|
|
mov ss, eax
|
|
|
|
mov esp, 0x800000 - 128
|
|
|
|
mov eax, gdt.tss
|
|
ltr ax
|
|
|
|
;rust init
|
|
mov eax, [kernel_base + 0x18]
|
|
mov [interrupts.handler], eax
|
|
mov eax, gdtr
|
|
mov ebx, idtr
|
|
mov ecx, tss
|
|
int 255
|
|
.lp:
|
|
sti
|
|
hlt
|
|
jmp .lp
|
|
|
|
gdtr:
|
|
dw gdt.end + 1 ; size
|
|
dd gdt ; offset
|
|
|
|
gdt:
|
|
.null equ $ - gdt
|
|
dq 0
|
|
|
|
.kernel_code equ $ - gdt
|
|
istruc GDTEntry
|
|
at GDTEntry.limitl, dw 0xFFFF
|
|
at GDTEntry.basel, dw 0
|
|
at GDTEntry.basem, db 0
|
|
at GDTEntry.attribute, db attrib.present | attrib.user | attrib.code | attrib.readable
|
|
at GDTEntry.flags__limith, db 0xFF | flags.granularity | flags.default_operand_size
|
|
at GDTEntry.baseh, db 0
|
|
iend
|
|
|
|
.kernel_data equ $ - gdt
|
|
istruc GDTEntry
|
|
at GDTEntry.limitl, dw 0xFFFF
|
|
at GDTEntry.basel, dw 0
|
|
at GDTEntry.basem, db 0
|
|
at GDTEntry.attribute, db attrib.present | attrib.user | attrib.writable
|
|
at GDTEntry.flags__limith, db 0xFF | flags.granularity | flags.default_operand_size
|
|
at GDTEntry.baseh, db 0
|
|
iend
|
|
|
|
.user_code equ $ - gdt
|
|
istruc GDTEntry
|
|
at GDTEntry.limitl, dw 0xFFFF
|
|
at GDTEntry.basel, dw 0
|
|
at GDTEntry.basem, db 0
|
|
at GDTEntry.attribute, db attrib.present | attrib.ring3 | attrib.user | attrib.code | attrib.readable
|
|
at GDTEntry.flags__limith, db 0xFF | flags.granularity | flags.default_operand_size
|
|
at GDTEntry.baseh, db 0
|
|
iend
|
|
|
|
.user_data equ $ - gdt
|
|
istruc GDTEntry
|
|
at GDTEntry.limitl, dw 0xFFFF
|
|
at GDTEntry.basel, dw 0
|
|
at GDTEntry.basem, db 0
|
|
at GDTEntry.attribute, db attrib.present | attrib.ring3 | attrib.user | attrib.writable
|
|
at GDTEntry.flags__limith, db 0xFF | flags.granularity | flags.default_operand_size
|
|
at GDTEntry.baseh, db 0
|
|
iend
|
|
|
|
.user_tls equ $ - gdt
|
|
istruc GDTEntry
|
|
at GDTEntry.limitl, dw 0xFFFF
|
|
at GDTEntry.basel, dw 0
|
|
at GDTEntry.basem, db 0
|
|
at GDTEntry.attribute, db attrib.present | attrib.ring3 | attrib.user | attrib.writable
|
|
at GDTEntry.flags__limith, db 0xFF | flags.granularity | flags.default_operand_size
|
|
at GDTEntry.baseh, db 0
|
|
iend
|
|
|
|
.tss equ $ - gdt
|
|
istruc GDTEntry
|
|
at GDTEntry.limitl, dw (tss.end - tss) & 0xFFFF
|
|
at GDTEntry.basel, dw (tss-$$+0x7C00) & 0xFFFF
|
|
at GDTEntry.basem, db ((tss-$$+0x7C00) >> 16) & 0xFF
|
|
at GDTEntry.attribute, db attrib.present | attrib.ring3 | attrib.tssAvailabe32
|
|
at GDTEntry.flags__limith, db ((tss.end - tss) >> 16) & 0xF
|
|
at GDTEntry.baseh, db ((tss-$$+0x7C00) >> 24) & 0xFF
|
|
iend
|
|
.end equ $ - gdt
|
|
|
|
struc TSS
|
|
.prev_tss resd 1 ;The previous TSS - if we used hardware task switching this would form a linked list.
|
|
.esp0 resd 1 ;The stack pointer to load when we change to kernel mode.
|
|
.ss0 resd 1 ;The stack segment to load when we change to kernel mode.
|
|
.esp1 resd 1 ;everything below here is unused now..
|
|
.ss1 resd 1
|
|
.esp2 resd 1
|
|
.ss2 resd 1
|
|
.cr3 resd 1
|
|
.eip resd 1
|
|
.eflags resd 1
|
|
.eax resd 1
|
|
.ecx resd 1
|
|
.edx resd 1
|
|
.ebx resd 1
|
|
.esp resd 1
|
|
.ebp resd 1
|
|
.esi resd 1
|
|
.edi resd 1
|
|
.es resd 1
|
|
.cs resd 1
|
|
.ss resd 1
|
|
.ds resd 1
|
|
.fs resd 1
|
|
.gs resd 1
|
|
.ldt resd 1
|
|
.trap resw 1
|
|
.iomap_base resw 1
|
|
endstruc
|
|
|
|
tss:
|
|
istruc TSS
|
|
at TSS.esp0, dd 0x800000 - 128
|
|
at TSS.ss0, dd gdt.kernel_data
|
|
at TSS.iomap_base, dw 0xFFFF
|
|
iend
|
|
.end:
|