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[eightysix] / kern / src / boot.asm

diff --git a/kern/src/boot.asm b/kern/src/boot.asm
index 96506de..25486e6 100644 (file)
--- a/kern/src/boot.asm
+++ b/kern/src/boot.asm
@@ -3,18 +3,19 @@
        bits 16
        section .bootsect
 
-extern _stage2_start_seg
-extern _stage2_size
+extern _bootsect_start
+extern _kern_start_seg
+extern _kern_size
 
-boot_driveno   equ 7b00h
-num_read_tries equ 7b06h       ; 2 bytes
-sect_pending   equ 7b08h       ; 2 bytes
-sect_per_track equ 7b0ah       ; 2 bytes
-cur_head       equ 7b0ch       ; 2 bytes - current head
-start_sect     equ 7b0eh       ; 2 bytes - start sector in track
-destptr                equ 7b10h       ; 2 bytes - destination pointer
-num_heads      equ 7b12h       ; 2 bytes - number of heads
-cur_cyl                equ 7b14h       ; 2 bytes - current cylinder
+boot_driveno   equ 0500h
+num_read_tries equ 0506h       ; 2 bytes
+sect_pending   equ 0508h       ; 2 bytes
+sect_per_track equ 050ah       ; 2 bytes
+cur_head       equ 050ch       ; 2 bytes - current head
+start_sect     equ 050eh       ; 2 bytes - start sector in track
+destptr                equ 0510h       ; 2 bytes - destination pointer
+num_heads      equ 0512h       ; 2 bytes - number of heads
+cur_cyl                equ 0514h       ; 2 bytes - current cylinder
 
 %macro floppy_motor_off 0
        pushf
@@ -57,7 +58,7 @@ bios_param_block:
        db 0            ; 25h: winnt flags
        db 28h          ; 26h: signature(?)
        dd 0            ; 27h: volume serial number
-       db "80 SIX BOOT"; 2bh: volume label, 11 bytes
+       db "86BOOT     "; 2bh: volume label, 11 bytes
        db "FAT12   "   ; 36h: filesystem id, 8 bytes
 
 start:
@@ -65,13 +66,18 @@ start:
        xor ax, ax
        mov ds, ax
        mov es, ax
+       mov ss, ax
+       mov [boot_driveno], dl  ; save boot drive number
+
+       ; relocate boot sector to 600h
+       mov si, 0x7c00
+       mov di, _bootsect_start
+       mov cx, 256
+       rep movsw
+
        jmp 00:.setcs
 .setcs:
-       ; put the stack high
-       mov ax, 0x7f00
-       mov ss, ax
-       xor sp, sp
-       mov [boot_driveno], dl
+       mov sp, _bootsect_start ; temp stack below our relocated address
 
        ; query sectors per track
        mov ah, 8       ; get drive parameters call, dl already has the drive
@@ -92,13 +98,13 @@ start:
 .querydone:
 
        ; load the rest of the code high
-       mov ax, _stage2_size
+       mov ax, _kern_size
        add ax, 511
        mov cl, 9
        shr ax, cl
        inc ax
        mov [sect_pending], ax
-       mov ax, _stage2_start_seg
+       mov ax, _kern_start_seg
        mov es, ax      ; destination segment
        mov word [destptr], 0
        mov word [start_sect], 1        ; start from sector 1 to skip boot sector
@@ -173,7 +179,7 @@ start:
        jnz .rdloop
 
        ; loaded sucessfully, load segment registers and jump
-.done: mov ax, _stage2_start_seg
+.done: mov ax, _kern_start_seg
        mov ds, ax
        mov es, ax
        push ax
@@ -248,7 +254,7 @@ print_hex_digit:
 
 str_rdtrack2   db " from ",0
 str_rdtrack3   db "/",0
-str_load_fail  db "Failed to load 2nd stage!",0
+str_load_fail  db "Failed to load kernel!",0
 str_newline    db 13,10,0
 
        times 510-($-$$) db 0