working on bootloaders (lba)

1 files changed, 95 insertions, 7 deletions

diff --git a/boot/disk_load_16.asm b/boot/disk_load_16.asm
index 2a209fc..764b80d 100644
--- a/boot/disk_load_16.asm
+++ b/boot/disk_load_16.asm
@@ -27,14 +27,79 @@ LBA:
 
 disk_load_16:
 
+   ; check if LBA is supported
+    mov    ah,0x41
+    mov    bx,0x55aa
+    int    0x13                                                    
+    jnc disk_load_lba
+    jmp disk_load_chs
+
+
+;#######################
+
+disk_load_lba:
+
     pusha
 
     mov bx,0x1000	;target es:bx
     mov es,bx
     mov bx,0
 
-    next_sectors:
+    next_sectors_lba:
 
+    ;show es - target
+    pusha
+    mov bx,es
+
+    mov al,bh
+    call print_hex_byte
+
+    mov al,bl
+    call print_hex_byte
+    popa
+    ;--
+
+    mov [lba_addr_sector],es
+    mov ax,[LBA]
+    mov [lba_first_sector],ax
+
+    mov dl,[BOOT_DRIVE]
+
+    mov ah,0x42
+    mov bx,0
+    mov ds,bx
+    lea si,[lba_adr]        
+    int 0x13  
+    jc disk_read_error
+
+    mov bx,es
+    add bx,0x0200
+    cmp bx,0x9e00
+    je disk_load_finish
+
+    mov es,bx
+    mov bx,0
+
+    mov ax,[LBA]
+    add ax,16
+    mov [LBA],ax
+
+    jmp next_sectors_lba
+
+;#######################
+
+
+disk_load_chs:
+
+    pusha
+
+    mov bx,0x1000	;target es:bx
+    mov es,bx
+    mov bx,0
+
+    next_sectors_chs
+
+    jmp skip_debug
     pusha
 
     mov bx, STR_SPACE
@@ -82,7 +147,13 @@ disk_load_16:
 
     call print_nextline
 
+    skip_debug
 
+
+    mov ax,[LBA]
+
+    ;calculate chs
+    call lba_to_chs
     ; and now READ it!
     mov al,16		;number of sectors to read
     mov dl,[BOOT_DRIVE]
@@ -91,7 +162,6 @@ disk_load_16:
     int 0x13		;bios interrupt
 
     jc disk_read_error
-    disk_read_error_continue:
 
     mov bx,es
     add bx,0x0200
@@ -105,15 +175,13 @@ disk_load_16:
     add ax,16
     mov [LBA],ax
 
-    jmp next_sectors
+    jmp next_sectors_chs
 
-    disk_read_error:
-    pusha
+disk_read_error:
     mov bx, STR_ERROR
     call print_string
     call print_nextline
-    popa
-    jmp disk_read_error_continue
+    jmp $
 
 disk_load_finish:
     
@@ -146,3 +214,23 @@ lba_to_chs:
           mov     ch, al		            ; not much else to do :)
           ret
 
+;; here we hold the lba addr
+lba_adr:
+
+    dw 0x10	    ; size of packet ( 16 byte)
+    dw 16	    ; number of sectors to read
+
+    ; target is 0x10000
+
+    dw 0x0000	    ; target addr. offset
+
+lba_addr_sector:
+    dw 0x1000	    ; target addr. sector
+
+lba_first_sector:
+    dw 10	    ; first sector to read
+    dw 0
+
+    dd 0 
+
+    ;