increased size of stage 2 bootloader by 1024 bytes

4 files changed, 24 insertions, 14 deletions

diff --git a/src/boot/boot.asm b/src/boot/boot.asm
index c3cb57e..75ad05e 100644
--- a/src/boot/boot.asm
+++ b/src/boot/boot.asm
@@ -106,7 +106,7 @@ stage2:
 	call print_string
 
 
-; load kernel to 0x8400 (directly  after stage 2
+; load kernel to 0x8800 (directly  after stage 2
 ; of the boot loader)	
 	mov dl, [BOOT_DRIVE]
 	call read_from_disk
@@ -220,8 +220,11 @@ MESSAGE_HALTED:
 %include "boot/stage2_check_magic.asm"
 
 ; make sure we have full sectors, stage 1 is 512 bytes, so we
-; have to will up 3 sectors
-times 2048-($-$$) db 0
+; have to will up 5 sectors (gives 6 in total for stage 1 and 2)
+times 3070-($-$$) db 0
 
-; position is 0x8400 now for the C entry
+; magic number of stage 2
+dw 0xAABB
+
+; position is 0x8800 now for the C entry
 kernel_main:
diff --git a/src/boot/stage1_functions.asm b/src/boot/stage1_functions.asm
index bdb2aac..f1d229b 100644
--- a/src/boot/stage1_functions.asm
+++ b/src/boot/stage1_functions.asm
@@ -1,3 +1,6 @@
+; NOF_SECTORS_STAGE2
+NOF_SECTORS_STAGE2 equ 5
+
 ; IN dx: hex value to print	
 print_hex:
 	push bx
@@ -88,7 +91,7 @@ current_row:
 read_stage2_from_disk:
 	mov ah, 0x02			; read sectors from drive
 	
-	mov al, 3			; read 3 sectors of stage 2
+	mov al, NOF_SECTORS_STAGE2	; read sectors of stage 2
 	mov ch, 0			; select first cylinder
 	mov dh, 0			; first head
 	mov cl, 2			; second sector after boot sector
@@ -101,7 +104,7 @@ read_stage2_from_disk:
 	
 	jc .read_error
 	
-	cmp al, 3			; 3 sectors read?
+	cmp al, NOF_SECTORS_STAGE2	; correct number of sectors read?
 	jne .short_read			; if not, short read
 	
 	ret
diff --git a/src/boot/stage2_check_magic.asm b/src/boot/stage2_check_magic.asm
index 1deaf05..7339a89 100644
--- a/src/boot/stage2_check_magic.asm
+++ b/src/boot/stage2_check_magic.asm
@@ -8,7 +8,7 @@ check_magic:
 	push edi
 	mov eax, NOF_LOAD_SECTORS	; number of 512-byte sectors
 	shl eax, 9			; 512 bytes per sector
-	mov edx, 0x8400			; offset of kernel
+	mov edx, 0x8800			; offset of kernel
 	add edx, eax
 	sub edx, MAGICLEN		; subtract the length of the magic string
 	mov esi, edx			; now use edx as first string address to compare to
@@ -20,12 +20,16 @@ check_magic:
 .ok:
 	mov si, MAGIC_OK_MSG
 	call pm_print_string
+	mov edx, esi
+	call pm_print_hex
 	call pm_print_newline
 	xor eax, eax
 	jmp .end
 .mismatch:
 	mov si, MAGIC_NOT_OK_MSG
 	call pm_print_string
+	mov edx, esi
+	call pm_print_hex
 	call pm_print_newline
 	xor eax, eax
 	mov eax, 1
@@ -42,7 +46,7 @@ db "ABAOS", %[MAGIC], 0
 MAGICLEN equ $ - COMPARE_MAGIC
 
 MAGIC_NOT_OK_MSG:
-db "Magic signature found", 0
+db "Magic signature found at ", 0
 
 MAGIC_OK_MSG:
-db "Magic signature not found!", 0
+db "Magic signature not found at ", 0
diff --git a/src/boot/stage2_real_functions.asm b/src/boot/stage2_real_functions.asm
index 87642c2..84713d5 100644
--- a/src/boot/stage2_real_functions.asm
+++ b/src/boot/stage2_real_functions.asm
@@ -1,8 +1,8 @@
 ; number of sectors to be read for the kernel itself
 ; (note: the first sector gets loaded by the BIOS, the
-; next 3 sectors are read by the simple stage 1 loader,
-; so subtract 3 here!)
-NOF_LOAD_SECTORS equ 44
+; next 5 sectors are read by the simple stage 1 loader,
+; so subtract 5 here!)
+NOF_LOAD_SECTORS equ 42
 
 ; data sections used for reading the kernel from disk
 SECTORS_PER_CYLINDER:
@@ -13,7 +13,7 @@ NOF_HEADS:
 SECTORS_TO_LOAD:
 	db NOF_LOAD_SECTORS		; load NOF_LOAD_SECTORS sectors in total
 CURRENT_SECTOR:
-	db 5				; first sector after stage 2
+	db 7				; first sector after stage 2
 CURRENT_CYLINDER:
 	db 0
 CURRENT_HEAD:
@@ -90,7 +90,7 @@ read_from_disk:
 
 	mov bx, 0			; where to store the data
 	mov es, bx
-	mov bx, 0x8400			; 2'048 bytes after first sector
+	mov bx, 0x8800			; 3072 bytes after first sector
 
 .read_next_sector: