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Diffstat (limited to 'boot/acer/mbr.asm')
| -rw-r--r-- | boot/acer/mbr.asm | 167 |
1 files changed, 167 insertions, 0 deletions
diff --git a/boot/acer/mbr.asm b/boot/acer/mbr.asm new file mode 100644 index 0000000..b3ae034 --- /dev/null +++ b/boot/acer/mbr.asm @@ -0,0 +1,167 @@ +;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; +; +; THE FOOL-BOOT-LOADER +; +; So we have just been loaded by the BIOS and are in 16-bits real mode! +; Now the following work will bee accomplished (chronologically): +; +; * BOOT_DRIVE set +; +; * 50 sectors of our kernel loaded at KERNEL_OFFSET from floppy +; +; * memory map made available at MEMMAP_OFFSET +; (check at MEMMEP_SIZE_OFFSET for number of entries) +; +; * the VESA mode specified by VESA_MODE_SELECT will be set up +; (check at VESA_MODES, and VESA_MODE_INFO +; for additional information) +; +; * interrupts disabled +; +; * 32-bit protected mode set up. +; +; * esp set to 0x90000 (Todo: take care of it!?) +; +; * A20 gate opened (Todo: really necessary?) +; +; * PICs configured +; +; * and finally we will jump into the C world to kernel_main() ! +; +;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; + +;we want 16-bit instructions, before we switch to 32-bit protected mode. +[bits 16] + +;define origin of boot record in memory: 0x7c00 +;this is where the BIOS per definition will put the first +;512 bytes of data from the boot device +;The Boot record is identified by the last 2 magic bytes: 0xaa55 (?) +[org 0x7c00] + +;;define some constants +;;where we will load our kernel into memory and some +;;other memory locations +; +KERNEL_OFFSET equ 0x1000 +MEMMAP_SIZE_OFFSET equ 0x7c00+0x600 +MEMMAP_OFFSET equ 0x7c00+0x400 +VESA_MODES equ 0x8300 +VESA_MODE_INFO equ 0x8400 +VESA_MODE_SELECT equ 0x4114 +;VESA_MODE_SELECT equ 0x0 +; +jmp boot_16 ;start boot process +; +;;SOME Global Data, mainly info/error strings +BOOT_DRIVE: + db 0xff +STR_VERSION: + db "v0.3.1~",0 +VESA_CHECK1: + db " V1.",0 +VESA_CHECK2: + db " V2",0 +VESA_CHECK3: + db " V3",0 +CHECK_A20: + db " A20",0 +; +;;lets put our temporary GDT (Global Descriptor Table) here +;;kernel should move this away +%include "boot/GDT.asm" +; +;;include 16-bit real mode routines (print_string, disk_load, vesa_setup,check_a20) +%include "boot/disk_load_16.asm" +;%include "boot/check_a20_16.asm" +%include "boot/print_string_16.asm" +%include "boot/vesa_setup_16.asm" +; +;;include our routines for switching to 32-bit protected mode +%include "boot/pm.asm" +; +;;pic_setup mapping routing +%include "boot/pic.asm" +; +;;get memory map routine +%include "boot/memmap.asm" +; +;;;;;;;;; BOOT 16-bit real ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; +; +;;lets start +[bits 16] +; +boot_16: +; +; + mov bx, STR_VERSION + call print_string +; +; +; ;setup the stack + mov bp,0x8000 + mov sp,bp +; +; ;remember BOOT_DRIVE (as was set by BIOS) + mov [BOOT_DRIVE],dl +; +; ;Load the KERNEL (52 sectors starting at sector 2) + mov bx,KERNEL_OFFSET + mov dh, 52 + mov dl, [BOOT_DRIVE] + call disk_load + + mov bx, KERNEL_OFFSET + call print_string + +; +; ;get memory map from bios before we enter 32 bit protected mode + mov ax,0 ; set target address in es:di (0:offset) + mov es,ax + mov di,MEMMAP_OFFSET + call BiosGetMemoryMap ; this will also put the number of entries +; ; of the memory map at MEMMAP_SIZE_OFFSET +; +;a20check: +; +; mov bx, CHECK_A20 +; call print_string +; +; call check_a20 +; cmp ax,0 +; je a20check ;hang if a20 is disabled! +; +; ;VESA: also setup vesa stuff before entering 32 bit protected mode + call VesaSetup +; +; ;finally lets enter Protected mode!!! + call switch_to_pm +; +;;;;;;;;; BOOT 32-bit protected mode;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; +[bits 32] +boot_32_pm: +; +;; we could do ALL This inside the kernel!!!!!! TODO +; +; ;enable A20 +; ;http://www.brokenthorn.com/Resources/OSDev9.html +; ;Method 3.1: Enables A20 through keyboard controller +; ;Not all keyboard controllers support this +; ;todo: check if this has any effect at all !?!? + mov al, 0xdd ; command 0xdd: enable a20 +; ;mov al, 0xdf ; command 0xdf: disable a20 + out 0x64, al ; send command to controller + +; +; ;pic setup + call pic_setup + +; + call KERNEL_OFFSET ;jump into our Kernel! +; +;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; +; +;so we get identified as MBR +times 510-($-$$) db 0x0 +dw 0xaa55 + |