568 lines
9.6 KiB
NASM
568 lines
9.6 KiB
NASM
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%include "bootdef.inc"
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%define VESA_MODEINFO_SEG 0x0120
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%define VESA_MODELIST_SEG 0x0140
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%define GOOD_MODELIST_SEG 0x0160
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[bits 16]
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org BOOT_STAGE2_ADD
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;k now read root directory
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mov bx, BOOT_ROOT_SEG
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mov ds, bx
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xor si, si ;k now ds:si points to beginning of root directory
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mov es, si
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mov cx, 224 ;max root entries
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loop_compare:
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mov di, kernel
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push cx
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push si ;save pointer to root dir entry
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mov cx, 11
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loop_name:
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cmpsb
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loopz loop_name
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jnz goon ;cx didn't get to zero, bad file
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pop si
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pop cx
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jmp found_file ;good file, ds:si points to start of root directory entry
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goon:
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pop si
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pop cx
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loop loop_compare
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error:
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jmp $ ;halt! no kernel file found!
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found_file: ;ds:si points to root dir entry of kernel file
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xor ax, ax
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mov gs, ax
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mov ax, [ds:si+26]
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mov bx, BOOT_FAT_SEG
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mov ds, bx ;ds points to beginning of FAT
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mov edi, BOOT_KERNEL_ADD
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readkernel_loop:
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cmp ax, 0xff7
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jg readkernel_done
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push ax
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call getCHSfromCluster
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mov ax, 0x0201
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mov dl, [gs:BOOT_DRIVE]
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mov bx, BOOT_KERNEL_SEG
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mov es, bx
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xor bx, bx
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int 0x13
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mov cx, 256
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xor ax, ax
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mov es, ax
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mov esi, BOOT_KERNEL_SEG*16
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copykernel_loop:
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mov ax, [es:esi]
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mov [es:edi], ax
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inc esi
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inc esi
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inc edi
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inc edi
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loop copykernel_loop
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pop ax ;current logical cluster #
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mov cx, ax ;cx=logical cluster
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mov dx, 3
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mul dx
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shr ax, 1 ;ax=logical cluster * 3 / 2
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mov si, ax
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test cl, 1 ;is bit0 set?
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jnz odd_cluster
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even_cluster:
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lodsw
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and ax, 0x0fff
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jmp got_cluster
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odd_cluster:
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lodsw
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shr ax, 4
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got_cluster:
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jmp readkernel_loop
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;------------------------------------------------------
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readkernel_done: ;-------------put more real mode init stuff here!
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;----ask to load RD from floppy
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mov ax, 0xb800
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mov es, ax
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xor ax, ax
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mov ds, ax
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xor di, di
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mov cx, 2000
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mov ax, 0x0700
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cls_loop:
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stosw
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loop cls_loop
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mov dx, 0x3d4 ;move cursor off screen...
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mov al, 0x0e
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out dx, al
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inc dx
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mov al, 0xff
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out dx, al
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dec dx
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mov al, 0x0f
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out dx, al
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inc dx
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out dx, al
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xor di, di
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mov si, txt_welcome
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mov ah, 0x1f
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call puts
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mov di, 160
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mov si, txt_rd1
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mov ah, 7
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call puts
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mov si, txt_rd2
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mov di, 160*2
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call puts
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mov di, 160*3
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mov si, txt_input
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call puts
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get_rd:
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xor ax, ax
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int 0x16
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cmp al, '1'
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jz got_rd
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cmp al, '2'
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jnz get_rd
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got_rd:
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stosb
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sub al, '1'
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push ds
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mov bx, BOOT_DATA_SEG ;segment for data to send kernel
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mov ds, bx
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mov [ds:BOOT_HASRD], al
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pop ds ;ds=0
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cmp al, 0 ;dont load rd
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jz no_rd
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mov cx, 80
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mov edi, 0xb8000+160*4
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filler_loop:
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mov word [ds:edi], 0x0400+177
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inc edi
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inc edi
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loop filler_loop
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mov cx, 80 ;80 cylinders to read
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xor si, si
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mov edi, BOOT_RD_ADD ;ram disk address
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read_cylinder:
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push cx
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mov bx, 0x0100
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mov es, bx
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xor bx, bx
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mov ax, 0x0224
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mov cx, si
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mov ch, cl
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mov cl, 1
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xor dx, dx
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mov dl, [gs:BOOT_DRIVE]
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int 0x13
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mov ebx, 0xb8000
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add bx, si
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shl bl, 1
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mov word [ds:ebx+160*4], 0x0200+219
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push si
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mov esi, 0x1000
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mov cx, 0x2400
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copydisk_loop:
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mov ax, [ds:esi]
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inc esi
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inc esi
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mov [ds:edi], ax
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inc edi
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inc edi
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loop copydisk_loop
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pop si ;what cylinder# we are on...
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inc si
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pop cx
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loop read_cylinder
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;------------------------------------------------------
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no_rd: ;done with ram disk, on to vesa info...
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xor ax, ax
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mov gs, ax
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mov ds, ax
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mov ax, 0xb800
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mov es, ax
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mov di, 160
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mov cx, 2000-80
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mov ax, 0x0700
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cls_vesa_loop:
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stosw
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loop cls_vesa_loop
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mov si, txt_vesa
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mov di, 160*1
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mov ah, 7
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call puts
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push di
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mov ax, 0x0100
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mov es, ax
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xor di, di
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mov dword [es:si], "2EBV"
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mov ax, 0x4F00
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int 0x10
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pop di
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cmp ax, 0x004F
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jz vesa_good
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mov si, txt_novesa
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mov ax, 0xb800
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mov es, ax
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mov ah, 7
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call puts
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mov ax, BOOT_DATA_SEG
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mov ds, ax
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mov word [ds:BOOT_VESA], 0
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jmp vesa_done
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vesa_good:
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mov ax, 0xb800
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mov es, ax
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mov ax, 0x0100
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mov ds, ax
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xor si, si
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mov bx, [4]
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mov al, bh
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call puthex
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mov al, '.'
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stosb
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mov al, 7
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stosb
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mov al, bl
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call puthex
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add di, 4
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cmp bh, 2
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jge vesa_good2
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xor ax, ax
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mov ds, ax
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mov si, txt_vesaold
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mov ah, 7
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call puts
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mov ax, BOOT_DATA_SEG
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mov ds, ax
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mov word [ds:BOOT_VESA], 0
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jmp vesa_done
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vesa_good2:
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mov ebx, [6] ;something like 0x00000E60
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mov edx, [14]
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mov si, bx
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shr ebx, 16
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mov ds, bx ;ds:si points to null-terminated OEM identification string
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mov ah, 2
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push si
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call puts
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pop si
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mov ax, BOOT_DATA_SEG
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mov es, ax
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mov di, BOOT_VESA_OEM
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vesa_copyoem:
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lodsb
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stosb
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or al, al
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jnz vesa_copyoem
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mov ax, 0x0100
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mov ds, ax
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xor si, si
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mov di, BOOT_VESA_VBE
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mov cx, 512
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vesa_copyvbe:
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lodsb
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stosb
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loop vesa_copyvbe
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mov si, dx
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shr edx, 16
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mov ds, dx ;ds:si points to video mode list
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mov ax, GOOD_MODELIST_SEG
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mov es, ax
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xor di, di
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vesa_copymodes:
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lodsw
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stosw
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cmp ax, 0xffff
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jnz vesa_copymodes
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mov ax, GOOD_MODELIST_SEG
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mov es, ax
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xor di, di
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mov cx, 256
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mov ax, 0xffff
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clear_good_mode_list_loop:
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stosw
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loop clear_good_mode_list_loop
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mov ax, VESA_MODELIST_SEG
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mov ds, ax
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xor si, si ;ds:si points to video mode list where we can edit it :)
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xor dx, dx ;dx=what good mode # we are on
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vesa_readmodeinfo_loop:
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mov ax, VESA_MODEINFO_SEG
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mov es, ax
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xor di, di
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lodsw
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cmp ax, 0xffff
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jnz vesa_notendofmodes
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jmp vesa_endofmodes
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vesa_notendofmodes:
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mov cx, ax
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mov ax, 0x4F01
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int 0x10
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call checkvesa
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xor di, di ;es:di -> ModeInfoBlock struc, ds:si -> video mode list
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mov ax, [es:di] ;ModeAttributes
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test al, 1 ;mode supported
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jz vesa_modenogood
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test al, 8 ;color mode
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jz vesa_modenogood
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test al, 0x10 ;graphics mode
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jz vesa_modenogood
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mov ax, [es:di+18] ;XResolution
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mov bx, [es:di+20] ;YResolution
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cmp ax, 640 ;640x480
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jnz res_goon1
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cmp bx, 480
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jnz vesa_modenogood
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jmp vesa_modegood
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res_goon1:
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cmp ax, 800
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jnz res_goon2
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cmp bx, 600
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jnz vesa_modenogood
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jmp vesa_modegood
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res_goon2:
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cmp ax, 1024
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jnz res_goon3
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cmp bx, 768
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jnz vesa_modenogood
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jmp vesa_modegood
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res_goon3:
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cmp ax, 1280
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jnz res_goon4
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cmp bx, 1024
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jz vesa_modegood
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cmp bx, 960
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jz vesa_modegood
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jmp vesa_modenogood
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res_goon4:
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cmp ax, 1600
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jnz vesa_modenogood
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cmp bx, 1200
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jnz vesa_modenogood
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vesa_modegood:
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mov ax, 0xb800
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mov es, ax
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mov ax, 160
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push dx
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mul dx ;ax=160*#ofgoodmode
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pop dx
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add ax, 160*2
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jmp vesa_readmodeinfo_loop
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vesa_modenogood:
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mov word [ds:si], 0
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jmp vesa_readmodeinfo_loop
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vesa_endofmodes:
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;------------------------------------------------------
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vesa_done:
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xor ax, ax ;wait for keypress...
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int 0x16
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jmp go_pm
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puts:
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lodsb
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or al, al
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jz puts_done
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stosb
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mov al, ah
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stosb
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jmp puts
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puts_done:
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ret
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checkvesa:
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cmp ax, 0x004F
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jnz vesaerror
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ret
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vesaerror:
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mov ax, 0xb800
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mov es, ax
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xor ax, ax
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mov ds, ax
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mov si, txt_vesaerror
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mov di, 160*24
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mov ah, 4
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call puts
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cli
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hlt
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;------------------------------------------------------
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puthex:
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;es:di points to video memory
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;al holds hex value
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push ax
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mov ah, al
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shr ax, 4
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and al, 0x0F
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add al, '0'
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cmp al, '9'
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jle puthex_goon1
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add al, 'A'-'9'-1
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puthex_goon1:
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cmp al, '0'
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jz puthex_skipzero
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stosb
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mov al, 7
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stosb
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puthex_skipzero:
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pop ax
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push ax
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and al, 0x0F
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add al, '0'
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cmp al, '9'
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jle puthex_goon2
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add al, 'A'-'9'-1
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puthex_goon2:
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stosb
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mov al, 7
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stosb
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pop ax
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ret
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;------------------------------------------------------
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puthex2:
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;es:di points to video memory, always displays 2 characters!
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;al holds hex value
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push ax
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mov ah, al
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shr ax, 4
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and al, 0x0F
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add al, '0'
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cmp al, '9'
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jle puthex2_goon1
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add al, 'A'-'9'-1
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puthex2_goon1:
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stosb
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mov al, 7
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stosb
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pop ax
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push ax
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and al, 0x0F
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add al, '0'
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cmp al, '9'
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jle puthex2_goon2
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add al, 'A'-'9'-1
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puthex2_goon2:
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stosb
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mov al, 7
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stosb
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pop ax
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ret
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;------------------------------------------------------
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txt_welcome: db " Welcome to HOS v", VERSION, "! ", 0
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txt_rd1: db "1. Do not load an initial ram disk", 0
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txt_rd2: db "2. Load initial ram disk from floppy", 0
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txt_input: db "Enter your selection: ", 0
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txt_vesa: db "VESA version: ", 0
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txt_vesaerror: db "VESA function call error! Halting system!", 0
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txt_novesa: db "VESA not found. Starting in console mode...", 0
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txt_vesaold: db "VESA version 2.0 required. Starting in console mode...", 0
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;------------------------------------------------------
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getCHSfromCluster:
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;input: ax=lba of sector on floppy (0-2879)
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add ax, 31 ;convert logical cluster# to lba#
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xor dx, dx ;lba->chs
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mov bx, 18
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div bx
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inc dx
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mov cl, dl ;sector# (1-18)
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xor dx, dx
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mov bx, 2
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div bx
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mov ch, al ;cylinder# (0-79)
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mov dh, dl ;head# (0-1)
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ret
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;-------------------------------------------------------
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gdtr:
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dw gdt_end-gdt-1
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dd gdt
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gdt:
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dd 0
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dd 0
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KERNEL_CODE equ $-gdt
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db 0xff ;limit 7:0
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db 0xff ;limit 15:8
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db 0x00 ;base 7:0
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db 0x00 ;base 15:8
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db 0x00 ;base 23:16
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db 0x9a ;access
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db 0xcf ;flags / limit 19:16
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db 0x00 ;base 31:24
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KERNEL_DATA equ $-gdt
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db 0xff ;segment 16 = 4gb data
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db 0xff
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db 0x00
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db 0x00
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db 0x00
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db 0x92
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db 0xcf ;cf
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db 0x00
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gdt_end:
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go_pm:
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xor ax, ax
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mov ds, ax
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lgdt [gdtr]
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cli
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mov eax, cr0
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inc eax
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mov cr0, eax
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jmp KERNEL_CODE:pmode
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bits 32
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pmode:
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mov ax, KERNEL_DATA
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mov es, ax
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mov ds, ax
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mov fs, ax
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mov gs, ax
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jmp KERNEL_CODE:BOOT_KERNEL_ADD
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kernel: db "KERNEL BIN"
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