Delete GDT-related files
This commit deletes the gdt.asm for the i386 architecture as it was quite buggy in that state. In a short while, the real GDT code which works is going to be committed.
This commit is contained in:
parent
993864e364
commit
0d49245a60
|
@ -1,223 +0,0 @@
|
|||
|
||||
GDT_MEMORY_AREA equ 0x20000
|
||||
GDT_ENTRIES_CAPACITY equ 8
|
||||
GDT_ENTRY_SIZE equ 8
|
||||
|
||||
db "gdt_set_segment"
|
||||
; [Furthest from EBP]
|
||||
; 3. Bool (Lowest Address) Task State Segment (0) or Code/Data (1)
|
||||
; Bool (Second-Lowest) Executable (1) or Not (0)
|
||||
; Bool (Second-Highest) Stack (1) or Heap (0) Page
|
||||
; Bool (Highest Address) Readable AND Writeable (1) or only what's necessary (0)
|
||||
; 2. U32 Number of pages
|
||||
; 1. Ptr32 Base address
|
||||
; 0. U32 Index of Segment (0 is not allowed)
|
||||
; [Nearest to EBP]
|
||||
gdt_set_segment:
|
||||
.prolog:
|
||||
push dword esi
|
||||
sub esp, 64
|
||||
mov esi, esp
|
||||
|
||||
mov [esi + (64 - 8)], ebx
|
||||
mov [esi + (64 - 12)], ecx
|
||||
mov [esi + (64 - 16)], edx
|
||||
mov [esi + (64 - 20)], edi
|
||||
|
||||
.get_work_address:
|
||||
mov eax, [ebp - 4]
|
||||
shl eax, 3
|
||||
add eax, GDT_MEMORY_AREA
|
||||
mov [esi], eax
|
||||
|
||||
.prepare_flags_and_access_byte:
|
||||
; Access Privilege
|
||||
; [Highest]
|
||||
; 7. Present Bit (Is in RAM: 1, is swapped out: 0)
|
||||
; 5+6. Descriptor Privilege Level (Kernel: 00, User; 11)
|
||||
; 4. Descriptor Type (0: System Segment, 1: Code or Data Segment)
|
||||
; 3. Is Executable? (Yes: 1, No: 0)
|
||||
; 2. Grows Up (Heap) / Grows Down (Stack: 0, Heap, 1)
|
||||
; 1. Secondary Access Bit (whether Read or Write is possible
|
||||
; even when it isn't strictly necessary for the segment type)
|
||||
; 0. Dirty Bit (Was Accessed: 1, Still Clean: 0)
|
||||
; [Lowest]
|
||||
|
||||
xor al, al
|
||||
or al, (1 << 7) ; Present-Bit
|
||||
|
||||
cmp [ebp - 16], byte 0
|
||||
je .after_task_segment_bit_setter
|
||||
or al, (1 << 4)
|
||||
.after_task_segment_bit_setter:
|
||||
|
||||
cmp [ebp - 15], byte 0
|
||||
je .after_executable_bit_setter
|
||||
or al, (1 << 3)
|
||||
.after_executable_bit_setter:
|
||||
|
||||
cmp [ebp - 14], byte 0
|
||||
je .after_direction_bit_setter
|
||||
or al, (1 << 2)
|
||||
.after_direction_bit_setter:
|
||||
|
||||
cmp [ebp - 13], byte 0
|
||||
je .after_read_write_bit_setter
|
||||
or al, (1 << 1)
|
||||
.after_read_write_bit_setter:
|
||||
|
||||
; Flags
|
||||
; [Highest]
|
||||
; 3. Address and Size Granularity (Bytes: 0, Pages: 1)
|
||||
; 2. 16-Bit or 32-Bit selector (0: 16-Bit, 1: 32-Bit)
|
||||
; 1. Long Mode / 64-Bit
|
||||
; 0. Reserved, should be 0
|
||||
; [Lowest]
|
||||
mov ah, (0b00001100 << 4)
|
||||
|
||||
; OR the uppermost 4 bits of the Limit into the
|
||||
; appropriate position in the byte of the flags.
|
||||
mov ecx, [ebp - 12]
|
||||
shr ecx, 16
|
||||
and ecx, 0b00001111
|
||||
or ah, cl
|
||||
|
||||
; Store the Access Byte and the Flags into the entry.
|
||||
mov ebx, [esi]
|
||||
mov [ebx + 5], al ; Access Byte
|
||||
mov [ebx + 6], ah ; Flags + Limit
|
||||
|
||||
mov eax, [ebp - 8] ; Base Address
|
||||
mov [ebx + 2], ax
|
||||
shr eax, 16
|
||||
mov [ebx + 3], al
|
||||
mov [ebx + 7], ah
|
||||
|
||||
mov ax, [ebp - 12]
|
||||
mov [ebx], ax
|
||||
|
||||
.epilog:
|
||||
mov ebx, [esi + (64 - 8)]
|
||||
mov ecx, [esi + (64 - 12)]
|
||||
mov edx, [esi + (64 - 16)]
|
||||
mov edi, [esi + (64 - 20)]
|
||||
|
||||
add esp, 64
|
||||
pop dword esi
|
||||
ret
|
||||
|
||||
|
||||
|
||||
db "load_flat_gdt"
|
||||
; [Furthest from EBP]
|
||||
; 0. 4B Return address
|
||||
; [Nearest to EBP]
|
||||
load_flat_gdt:
|
||||
.prolog:
|
||||
push dword esi
|
||||
sub esp, 64
|
||||
mov esi, esp
|
||||
|
||||
mov [esi + (64 - 8)], ebx
|
||||
mov [esi + (64 - 12)], ecx
|
||||
mov [esi + (64 - 16)], edx
|
||||
mov [esi + (64 - 20)], edi
|
||||
mov eax, [ebp - 4]
|
||||
|
||||
mov [esi + 20], eax
|
||||
|
||||
.create_gdt:
|
||||
|
||||
push ebp
|
||||
mov ebp, esp
|
||||
push dword (GDT_MEMORY_AREA - 16)
|
||||
push dword gdt_identifier_text
|
||||
push dword 8
|
||||
call mem_copy
|
||||
mov esp, ebp
|
||||
pop ebp
|
||||
|
||||
; Code Segment
|
||||
push ebp
|
||||
mov ebp, esp
|
||||
push dword 1
|
||||
push dword 0
|
||||
push dword 0xfffff
|
||||
push byte 1
|
||||
push byte 0
|
||||
push byte 1
|
||||
push byte 1
|
||||
call gdt_set_segment
|
||||
mov esp, ebp
|
||||
pop ebp
|
||||
|
||||
; Stack Segment
|
||||
push ebp
|
||||
mov ebp, esp
|
||||
push dword 2
|
||||
push dword LOWER_STACK_POINTER
|
||||
push dword 0fxffff
|
||||
push byte 1
|
||||
push byte 1
|
||||
push byte 0
|
||||
push byte 1
|
||||
call gdt_set_segment
|
||||
mov esp, ebp
|
||||
pop ebp
|
||||
|
||||
; Data Segment
|
||||
push ebp
|
||||
mov ebp, esp
|
||||
push dword 3
|
||||
push dword 0
|
||||
push dword 0xfffff
|
||||
push byte 1
|
||||
push byte 0
|
||||
push byte 1
|
||||
push byte 1
|
||||
call gdt_set_segment
|
||||
mov esp, ebp
|
||||
pop ebp
|
||||
|
||||
; Write the GDT Descriptor
|
||||
cli
|
||||
lgdt [.gdtr]
|
||||
|
||||
mov ax, (3 << 3)
|
||||
mov ds, ax
|
||||
mov es, ax
|
||||
mov fs, ax
|
||||
mov gs, ax
|
||||
mov ax, (2 << 3)
|
||||
mov ss, ax
|
||||
|
||||
; mov eax, cr0
|
||||
; or eax, 1
|
||||
; mov cr0, eax
|
||||
|
||||
cli
|
||||
jmp dword 1:.after_far_jump
|
||||
|
||||
.after_far_jump:
|
||||
mov eax, cr0
|
||||
or eax, 1
|
||||
mov cr0, eax
|
||||
|
||||
mov esi, [esi + 20]
|
||||
jmp esi
|
||||
|
||||
mov ebx, [esi + (64 - 8)]
|
||||
mov ecx, [esi + (64 - 12)]
|
||||
mov edx, [esi + (64 - 16)]
|
||||
mov edi, [esi + (64 - 20)]
|
||||
|
||||
|
||||
align 16
|
||||
.gdtr:
|
||||
.gdtr.length:
|
||||
dw 31
|
||||
.gdtr.address:
|
||||
dd GDT_MEMORY_AREA
|
||||
|
||||
gdt_identifier_text:
|
||||
db "GDT !!!!"
|
Loading…
Reference in New Issue