I am reading some code of Linux. The keyboard.S has something like
outb %al,$0x61
and
inb $0x61,%al
I think the pending 'b' means 'byte', but i still cannot find what these instructions mean.
I am reading some code of Linux. The keyboard.S has something like
outb %al,$0x61
and
inb $0x61,%al
I think the pending 'b' means 'byte', but i still cannot find what these instructions mean.
OUT
andIN
are instructions for transferring data between I/O ports. Those are a couple of links I found which provide a bit more information.As you mentioned, the
b
is thebyte
form of those instructions, which is appropriate since you're using the lower byte ofax
(al
).