Эмулятор процессора Intel 8086 версия 4.05 (ENG) / asm_files / writebin.asm

Assembler Source Code a:link {text-decoration: none} a:visited {text-decoration: none} a:hover {text-decoration: none; color:#ff0000}     ; writebin.asm name "writebin" ; version 0.02 ; assembled by emu8086 -- must be compatible with major assemblers. ; writebin.com -- a tiny operating system loader. ; writebin [filename] [/k] ; this utility is be used from command prompt, ; it reads a specified file and writes it to floppy drive at ; cylinder: 0, head: 0, sector: 1 (boot sector). ; if there is /k parameter after the file name, then the ; file is written at cylinder: 0, head: 0, sector: 2. ; first sector of a floppy drive is reserved for boot sector. ; second and other sectors can be used to store any kind of data ; and code. kernel module of tiny operating system should be ; written to sector 2. ; this program works with drive A: only. ; for emulator drive A: is c:\emu8086\FLOPPY_0 ; filename must be in 8.3 format, ; maximum 8 chars for the name and 3 chars after the dot. ; warning! if you run this program outside of the emulator ; it may corrupt existing data. use with caution. ; do not play with floppies that contain valuable data. org 100h jmp st filename db 128 dup(0) ; full path up to 128 chars can be specified. buffer db 512 dup (0) buffer_size = $ - offset buffer handle dw 0 kernel_flag db 0 ; if there is /k parameter, kernel_flag=1. counter dw 0 sect db 1 ; sector number (1..18). cyld db 0 ; cylinder number (0..79). head db 0 ; head number (0..1). drive db 0 ; drive number (0..3) ; A:=0, B:=1... ; init st: mov ax, cs mov ds, ax mov es, ax call clear_screen ; read cmd parameters cp: xor cx, cx mov cl, [80h] jcxz np ; this instruction is assembled into OR CX, CX and two JMPs, tutorial 7 tells why. mov si, 82h mov di, offset filename cld rep movsb mov [di-1], 0 ; check for /k parameter: cld xor cx, cx mov cl, [80h] mov di, offset filename mov al, '/' repne scasb jz fs jmp boot fs: cmp [di-2], ' ' jne nsp mov [di-2], 0 nsp:mov [di-1], 0 or [di], 0010_0000b ; to lower case. cmp [di], 'k' jne wp or kernel_flag, 1 mov sect, 2 ; start write at sector 2. lea dx, s0 mov ah, 9 int 21h jmp s0s s0 db 0Dh,0Ah,"[/k] - start from sector: 2 " , 0Dh,0Ah, '$' s0s: jmp of boot: lea dx, s3 mov ah, 9 int 21h jmp s3s s3 db 0Dh,0Ah," boot record ", 1 , 0Dh,0Ah, '$' s3s: ; open file of: mov ah, 3dh mov al, 0 mov dx, offset filename int 21h jc co mov handle, ax lea dx, m0 mov ah, 9 int 21h jmp m0m m0 db "opened: $" m0m: mov si, offset filename call print_string ; read bytes from file rd: mov ah, 3fh mov bx, handle mov cx, buffer_size mov dx, offset buffer int 21h jc er cmp ax, 0 ; no bytes left? jz cf ; write bytes to disk wr: mov ah, 03h mov al, 1 ; write 1 sector (512 bytes). mov cl, sect ; sector (1..18) mov ch, cyld ; cylinder (0..79) mov dh, head ; head (0..1) mov dl, drive ; always 0 (A:) mov bx, offset buffer int 13h jc er inc counter ; set cursor at 2,5 mov ah, 2 mov dh, 5 mov bh, 0 int 10h ; show current progress: lea dx, s1 mov ah, 9 int 21h jmp s1s s1 db 1Dh,0Ah,"writing: $" s1s: mov ax, counter call print_num_uns ; sectors... cylinders... heads... cmp kernel_flag, 1 jne cf inc sect cmp sect, 18 jbe rd ; ^ mov sect, 1 inc cyld cmp cyld, 79 jbe rd ; ^ mov cyld, 0 inc head cmp head, 1 jbe rd ; ^ ; close file cf: mov bx, handle mov ah, 3eh int 21h jc er jmp ex co: lea dx, e0 mov ah, 9 int 21h jmp e0e e0 db " cannot open the file...",0Dh,0Ah,'$' e0e: jmp ex np: lea dx, e1 mov ah, 9 int 21h jmp e1e e1 db " no parameters...",0Dh,0Ah db "==============================================================================",0Dh,0Ah db "this program was designed especially to test micro-operating system",0Dh,0Ah db "if you are emulating in emu8086, click file->set command line parameters.",0Dh,0Ah db "from command prompt type:", 0Dh,0Ah db " writebin [filename] [/k]",0Dh,0Ah, db "when /k parameter is specified file is written to second sector (kernel area).",0Dh,0Ah, db "==============================================================================",0Dh,0Ah,'$' e1e: jmp ex er: lea dx, e2 mov ah, 9 int 21h jmp e2e e2 db " i/o error...",0Dh,0Ah,'$' e2e: jmp ex wp: lea dx, e3 mov ah, 9 int 21h jmp e3e e3 db " wrong parameter. only [/k] is supported. use 8.3 short file names only.",0Dh,0Ah,'$' e3e: ex: lea dx, m1 mov ah, 9 int 21h jmp m1m m1 db 0Dh,0Ah," total sectors: $" m1m: mov ax, counter call print_num_uns lea dx, m2 mov ah, 9 int 21h jmp m2m m2 db 0Dh,0Ah, "thank your for using writebin! - emu8086.com - 2005 (c) freeware",0Dh,0Ah db " press any key...",0Dh,0Ah, '$' m2m: ; wait for any key... mov ah, 0 int 16h ret ; exit. ; this macro prints a char in AL and advances ; the current cursor position: PUTC MACRO char PUSH AX MOV AL, char MOV AH, 0Eh INT 10h POP AX PUTC ENDM ; prints out an unsigned value of AX register. ; allowed values from 0 to 65535 print_num_uns proc near push ax push bx push cx push dx ; flag to prevent printing zeros before number: mov cx, 1 ; (result of "/ 10000" is always less or equal to 9). mov bx, 10000 ; 2710h - divider. ; ax is zero? cmp ax, 0 jz print_zero begin_print: ; check divider (if zero go to end_print): cmp bx,0 jz end_print ; avoid printing zeros before number: cmp cx, 0 je calc ; if ax<bx then result of div will be zero: cmp ax, bx jb skip calc: mov cx, 0 ; set flag. mov dx, 0 div bx ; ax = dx:ax / bx (dx=remainder). ; print last digit ; ah is always zero, so it's ignored add al, 30h ; convert to ascii code. putc al mov ax, dx ; get remainder from last div. skip: ; calculate bx=bx/10 push ax mov dx, 0 mov ax, bx div cs:ten ; ax = dx:ax / 10 (dx=remainder). mov bx, ax pop ax jmp begin_print print_zero: putc '0' end_print: pop dx pop cx pop bx pop ax ret ten dw 10 ; used as divider. print_num_uns endp ; print null terminated string at ds:si print_string proc near push ax ; store registers... push si ; nxtch: mov al, [si] cmp al, 0 jz printed inc si mov ah, 0eh ; teletype function. int 10h jmp nxtch printed: pop si ; re-store registers... pop ax ; ret print_string endp clear_screen proc near push ax ; store registers... push ds ; push bx ; push cx ; push di ; mov ax, 40h mov ds, ax ; for getting screen parameters. mov ah, 06h ; scroll up function id. mov al, 0 ; scroll all lines! mov bh, 07 ; attribute for new lines. mov ch, 0 ; upper row. mov cl, 0 ; upper col. mov di, 84h ; rows on screen -1, mov dh, [di] ; lower row (byte). mov di, 4ah ; columns on screen, mov dl, [di] dec dl ; lower col. int 10h ; set cursor position to top ; of the screen: mov bh, 0 ; current page. mov dl, 0 ; col. mov dh, 0 ; row. mov ah, 02 int 10h pop di ; re-store registers... pop cx ; pop bx ; pop ds ; pop ax ; ret clear_screen endp ; some interrupt info: ; ----------------------------------------------------------- ; INT 21h / AH= 3Dh - open existing file. ; entry: ; ; AL = access and sharing modes (if unsure set to zero). ; DS:DX -> ASCIZ filename. ; return: ; CF clear if successful, AX = file handle. ; CF set on error AX = error code. ; Note: file pointer is set to start of file. ; ----------------------------------------------------------- ; INT 21h / AH= 3Fh - read from file. ; entry: ; BX = file handle. ; CX = number of bytes to read. ; DS:DX -> buffer for data. ; return: ; CF is clear if successful - AX = number of bytes actually read; 0 if at EOF (end of file) before call. ; CF is set on error AX = error code. ; note: data is read beginning at current file position, and the file position is updated after ; a successful read the returned AX may be smaller than the request in CX if a partial read occurred. ; ----------------------------------------------------------- ; INT 21h / AH= 3Eh - close file. ; entry: BX = file handle ; return: ; CF clear if successful, AX destroyed. ; CF set on error, AX = error code (06h). ; ----------------------------------------------------------- ; INT 13h / AH = 03h - write disk sectors. ; input: ; AL = number of sectors to read/write (must be nonzero) ; CL = sector number (1..18). ; CH = cylinder number (0..79). ; DH = head number (0..1). ; DL = drive number (0..3 , for the emulator it depends on quantity of FLOPPY_ files). ; ES:BX points to data buffer. ; return: ; CF set on error. ; CF clear if successful. ; AH = status (0 - if successful). ; AL = number of sectors transferred. ; Note: each sector has 512 bytes. ; ----------------------------------------------------------- ; INT 10h / AH = 02h - set cursor position. ; input: ; DH = row. ; DL = column. ; BH = page number (0..7). ; ----------------------------------------------------------- ; INT 21h / AH=09h - output of a string at DS:DX. ; string must be terminated by '$' character. ; -----------------------------------------------------------

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