LowID's LPL Log

부연설명 (잊어버릴까봐..)
mov ax,0 ; ax = 0
int 0x10  ;번호에 해당하는 인터럽트 발생
(쉽게 말해 ax,bx,cx,dx,같은게 인자고 이걸사용하면 함수를 부르는거라 생각하면 될듯)

inc  ax   ; ax ++
dec ax    ; ax--
add ax,3  ; ax = ax + 3
sub ax,3  ; ax = ax - 3

cmp ax,3  ; if문, ax가 (뒤에 따라 점프)
jmp lable; goto label
jc        : jump carry,에러가 난다면.. 점프
je        ; jump equal 같으면 점프
jb        ; jemp below 작으면 점프
jbe       ; jemp below equal 작거나 같으면 점프
jnc       ; jemp not carry

db        ; byte (db 0x00 이면 현재위치에 1byte 만큼 0을 쓴다 라는 뜻인듯)
dw        ;word  (마찬가지)
dd        ; double word (마찬가지)

[]         ; c와 같다(배열과 포인터에 나오는 그거임... *(변수))
$          ; 현재 위치
resb      ; 0로 범위까지 채운다 (nasm에는 없음 times로 대체)

;main
;Program start place
ORG 0x7c00

;#define READ_CYRINDERS 10
READ_CYLINDER EQU 10

;FAT12 Boot record setting
jmp init_register       ;Jump boot code (3byte)
db  0x90                 ;padding (jump boot code)
db  "Lowid   "           ;OEM Name (8byte)
dw  512                  ;Bytes per secter
db  1                     ;Secter per Cluster
dw  1                     ;Reserved Secter count
db  2                     ;Number of fats
dw  224                  ;Boot entry count
dw  2880                ;Total secter 16
db  0xf0                 ;Media(now,floppy disk)
dw  9                    ;Fat size 16
dw  18                   ;Sector per track
dw  2                    ;Number of heads
dd  0                    ;Hidden secter    (no use partition)
dd  2280                ;Total secter32?? (drive size)
db  0                    ;Drive Number
db  0                    ;Reseved1
db  0x29                ;Boot signature(must 0x29?)
dd  0xffffffff        ;Volume serial num??
db  "Lowid_vol  "       ;Volume label (11byte)
db  "FAT12   "          ;Filesystem Type (8byte)
resb 18

init_register:
    mov ax,0
    mov sp,0x7c00
    mov ds,ax
    mov ss,ax

;(Read)Segment + offset
    mov ax,0x0820
    mov es,ax
    mov bx,0

;init_CHS
    mov ch,0    ;Cyrinder
    mov dh,0    ;Head
    mov cl,2    ;Sector

init_di_register:
    mov di,0    ;error count

read_disk:
    mov ah,0x02 ;read_mode
    mov al,1    ;read secter size
    mov dl,0    ;drive
    int 0x13    ;disk nterrupt

    jnc succeed ;no error.. jump (read)succeed

    ;error
    inc di      ;di ++
    cmp di,5    ;if 5
    je error    ;equal.. goto error

    jmp read_disk

print:
    mov al,[si] ;print character
    mov ah,0x0e ;mode
    mov bh,0x15 ;color
    int 0x10    ;video interrupt

    inc si
    cmp al,0
    je finish

    jmp print

error:
    mov si,error_string
    jmp print

;MAX(floppy disk?) - cylinder:40, head:2 sector:18
;cylinder:0 head:0 sector:1
;cylinder:0 head:0 sector:2
;cylinder:0 head:0 sector:3
;         .......
;cylinder:0 head:0 sector:17
;cylinder:0 head:0 sector:18
;cylinder:0 head:1 sector:1
;cylinder:0 head:1 secter:2
;         .......
;cylinder:0 head:1 secter:17
;cylinder:0 head:1 secter:18
;cylinder:1 head:0 secter:1

succeed:
;Move Segment and offset
    mov ax,es
    add ax,512/16
    mov es,ax
;Read 18 secter
    inc cl
    cmp cl,18
    jbe init_di_register
;Read 2 head
    mov cl,0    ;init secter
    inc dh
    cmp dh,2
    jb  init_di_register
;Read 10 cylinder
    mov dh,0    ;init head
    inc ch
    cmp ch,READ_CYLINDER
    jb  init_di_register
;All compleate!.. print succeed
    mov si,succeed_string
    jmp print

;jemp! (video file)
finish:
    jmp 0xc200

error_string:
    db "Read Failed - Check please!!"
    db 0x0a,0x00

succeed_string:
    db "Read Succeed - Check OK !!"
    db 0x0a,0x00

    ;for Dos Table Signature
    resb 0x7dfe - $ ;padding(0)
    db 0x55,0xaa    ;Dos Table Signature

;video
ORG 0xc200

;VGA 320x200x8bit
mov al,0x13
mov ah,0x00
int 0x10

finish:
    hlt
    jmp finish

unsigned int  atox(char *string)
{ 
     unsigned int ret;

     sscanf(string,"%x",&ret);

    return ret;
}

 unsigned int get_value(unsigned char *segment,int offset,int size)
{
    int i;
    char temp[size * 2 + 1];
    unsigned char dt[size];
    temp[size * 2] = '\0';

    for(i = 0;i < size;i ++)
        /* 리틀 엔디언 */
        dt[size - i - 1] = *(segment + offset + i);

    if(size == 1)
        sprintf(temp,"%02x",dt[0]);
    else if(size == 2)
        sprintf(temp,"%02x%02x",dt[0],dt[1]);
    else if(size == 3)
        sprintf(temp,"%02x%02x%02x",dt[0],dt[1],dt[2]);
    else if(size == 4)
        sprintf(temp,"%02x%02x%02x%02x",dt[0],dt[1],dt[2],dt[3]);

    return atox(temp);
}

unsigned int get_value(unsigned char *segment,int offset,int size)
{
    int ts = 0;
  
    memcpy(&ts,segment + offset,size);

    return ts;
}