CODEWITHSUNDEEP
assemblynasmx86-16bootloaderreal-mode
Thon peter
Thon peter

Reputation: 1

Bootloader program that prints okay using nasm assembler

So I was trying to run the program below using NASM assembler. Since I wanted to tell the assembler that I wanted a plain binary file without any bells nor whistles, I used:

nasm -f -o boot.bin boot.asm Error: nasm fatal: unable to open input file 'boot.bin'

someone to please help out.Why did I get this error and how to solve it.

here is the code:

bits 16
start:
mov ax, 0x07C0     ;0x07C0 is where we are
add ax, 0x20       ;add 0x20 (when shifted 512)
mov ss,ax          ;set the stack segment
mov sp, 0x1000     ; set the stack pointer
mov ax, 0x07C0     ; set data segment
mov ds, ax         ;more about this later

mov si, msg        ;pointer to the message in SI
mov ah, 0x0E       ;print CHAR BIOS procedure

.next:
lodsb ;next byte to AL, increment SI
cmp al, 0 ;if the byte is zero
je .done ;jump do done
int 0x10 ;invoke the BIOS system call
jmp .next ;loop

.done:
jmp $ ;loop forever
msg: db 'ok',0  ;The string we want to print
times 510-($-$$) db 0  ;fill up to 510 bytes
dw 0xAA55 ;master boot record signature

Upvotes: 1

Views: 344

Answers (1)

Michael Petch
Michael Petch

Reputation: 47573

You specify BINary with the -f bin option in NASM. What you wanted was:

nasm -f bin -o boot.bin boot.asm

The default is binary if you don't specify -f so this would have worked as well:

nasm -o boot.bin boot.asm

Upvotes: 2

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