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ide - pio
Posted: Fri Dec 03, 2010 5:09 am
by vinise
Hy every one
I'm trying to read an ide hd but without sucess
I've read the wiki about pio but i still get some difficulty setting up the registers.
i'm using bochs with an hd image.
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ata0: enabled=1, ioaddr1=0x1f0, ioaddr2=0x3f0, irq=14
ata0-master: type=disk, path="C:\cygwin\dev\hd0", mode=flat, cylinders=4, heads=16, spt=63
and bock see it well on boot:
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ata0 master: Generic 1234 ATA-6 Hard-Disk ( 1 MBytes)
I can read it with od in shell:
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$ od -A d -c /dev/hd0
0000000 h e l l o \0 \0 \0 \0 \0 \0 \0 \0 \0 \0 \0
0000016 \0 \0 \0 \0 \0 \0 \0 \0 \0 \0 \0 \0 \0 \0 \0 \0
here is my configuration to read...
0x1f6<-0xA0
0x1f2<-0x1
0x1f3<-0x1
0x1f4<-0x0
0x1f5<-0x0
0x1f7<-0x20
and i read with this code...
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still_going:
in al,dx
test al,8
jz still_going.
mov cx,10 ;10 word
mov di, buffer
mov dx,0x1f0
rep insw
mov byte dl, [buffer+2]
call putchar
buffer: a buffer of 10 db
putchar: function with print the char in dl on the screen
any help will be pleased
Re: ide - pio
Posted: Fri Dec 03, 2010 5:13 am
by Combuster
A read is 512 bytes, you read 20 bytes (a word is two bytes!) into a 10-byte buffer, so you have a buffer overflow for starters.
Also, you might rather want to wait for both BUSY to be cleared and DRQ set.
Re: ide - pio
Posted: Fri Dec 03, 2010 7:59 am
by vinise
i did this.. is it better?
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still_going:
in al,dx
test al,8
jz still_going
test al,0x40
jnz still_going
mov cx,512/2
mov di, buffer
mov dx,1f0h
rep insw
mov ecx,0
affi:
mov byte dl, [buffer+ecx]
call putchar
inc ecx
cmp ecx,20
jb affi
buffer:
times 512 DB '0'
anny way is still not working
Re: ide - pio
Posted: Sat Dec 04, 2010 6:17 am
by vinise
Hy,
i've try to write on the disk instead of read. but i get a strange thing.
i try to write 512byte and when I check the disk with "od" i get five "1" and it's all.
If anny one could help me please
Re: ide - pio
Posted: Mon Dec 06, 2010 7:58 am
by thepowersgang
How useful... you failed to tell us what you are writing, and how the write code differs from your read code.
Also your code completely lacks commenting.
And as a final note, did you read the "Asking Smart Questions" link (it's linked from the forum rules)
Re: ide - pio
Posted: Mon Dec 06, 2010 8:39 am
by blackoil
read sector : set up registers, wait for irq, read 512 bytes
write sector : set up registers, write 512 bytes, wait for irq
the command register should be the last one to be written
Re: ide - pio
Posted: Mon Dec 06, 2010 8:43 am
by IanSeyler
Re: ide - pio
Posted: Mon Dec 06, 2010 4:09 pm
by bewing
The problem may be your value of ES: when you are trying to read -- but it looks like you are in real mode, still? Do you have interrupts turned off? If not, the BIOS is probably stealing all your data.
Re: ide - pio
Posted: Wed Dec 08, 2010 10:05 am
by vinise
Hy
Thanks for all your answers
the problems came from this line:
I made a mistake putting di instead of edi.
It's working well with bochs but when I try on a real computer it is not working.
Is it possible to acces to a real IDE hard drive with pio?