Finally we have a 2 stage bootloader !

This one can load the ramdis up to 0xfffff  :)

1 files changed, 133 insertions, 0 deletions

diff --git a/boot/stage2.asm b/boot/stage2.asm
new file mode 100644
index 0000000..27f9832
--- /dev/null
+++ b/boot/stage2.asm
@@ -0,0 +1,133 @@
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+;
+;   THE FOOL-BOOT-LOADER
+;    
+;	* X 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
+;
+;	* A20 gate opened 
+;
+;	* 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 0x7e00]
+
+;;define some constants
+;;where we will load our kernel into memory and some 
+;;other memory locations
+;
+KERNEL_DATA equ 10	;sector on disk where the kernel starts
+KERNEL_SECTOR equ 0x1000
+KERNEL_OFFSET equ 0x0000
+
+MEMMAP_SIZE_OFFSET equ 0x7c00
+MEMMAP_OFFSET equ 0x7c01
+VESA_MODES equ 0x8300
+VESA_MODE_INFO equ 0x8400
+VESA_MODE_SELECT equ 0x4114
+;
+jmp boot_16 ;start boot process
+
+;;SOME Global Data, mainly info/error strings
+BOOT_DRIVE:
+    db 0xff
+STR_VERSION:
+    db "Fool Loader Stage 2 v0.5",0
+
+VESA_CHECK1:
+    db "1",0
+VESA_CHECK2:
+    db "2",0
+VESA_CHECK3:
+    db "3",0
+CHECK_A20:
+    db "A",0
+STR_LOAD
+    db "Loading Kernel...",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"
+;
+;
+;;get memory map routine
+%include "boot/memmap.asm"
+;
+;;;;;;;;; BOOT 16-bit real ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+;
+;;lets start
+[bits 16]
+
+boot_16:
+
+
+;   pr info 
+    mov bx, STR_VERSION
+    call print_string
+    call print_nextline
+
+;   remember BOOT_DRIVE again
+    mov [BOOT_DRIVE],dl	
+
+;   Load the KERNEL Image
+    mov bx, STR_LOAD
+    call print_string
+    call print_nextline
+    call disk_load_16
+    
+    ;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
+    call VesaSetup
+   
+    call switch_to_pm
+;
+;;;;;;;;; BOOT 32-bit protected mode;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+[bits 32]
+boot_32_pm:
+
+    ;Fast A20 Gate:
+    ;http://wiki.osdev.org/A20_Line
+    
+    in al, 0x92
+    or al, 2
+    out 0x92, al
+
+    ; call kernel!
+    mov eax,0		;tell the kernel 
+			; we are the booting processor
+    call 0x10000        ;jump into our Kernel!
+