reading floppy

[suthers]

Im trying to load the kernel rom my bootloader.
I use the following code:

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	mov cx, 0x10
	.cylinder1
	mov ax,0x100000
	mov es,ax                     
	mov bx,0x10                   
	mov ah,2        	      
	mov al,17                     
	mov ch,0                      
	mov cl,2                      
	mov dh,0                      
	int 0x13                      
	jc .finish
	loop .cylinder1

and the following code to jump to it:

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jmp 08h:0x100000

But it just restarts any ideas why?
Thanks in advance,
Jules

[lukem95]

if its restarting it probably means its triple faulting (some computers + bochs) reboot when this happens.

[Combuster]

you've got your test the wrong way around it seems - you're looping until the read fails


And you can't fit 32 bits into a 16-bit register:

Code: Select all

mov ax,0x100000

So, fix your assembler warnings first


And IIRC some bioses don't like loading directly above 1MB anyway

[suthers]

If i change the jc to jnc it just goes into an infinite loop.
Also is there a convention on were to load the kernel?
If not anywere you would recommend loading it so it doesn't mess with anything else?
Thanks in advance,
Jules

[xyjamepa]

Hi...


If ther was a carry then the reading operation failed,
this means you should jump if there's no carry using "jnc"...
any way here's a simple .com program that loads the first sector
of the root directory and prints it,I'm talking about fat12 floppy driver.