How to understand this assembly instruction?

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inl instruction asm

there is several instructions in assembly language:
Code: 
	movw	$0xcf8,%dx
	movl	$0x80003840,%eax	#
	outl	%eax,%dx
	movb	$0xfc,%dl
	inl	%dx,%eax

how to understand the last instruction? what means "inl"?
could anyone provide the material on assembly instruction set?

Thanks a lot!
 

You didn't say the CPU type or assembler version, but the b/w/l opcode suffix usually means byte/word/long, which usually means 8/16/32 bit operand. So, "inl" probably means "input from 32 bit port".
 

to ease understanding the code, I'll just comment it rightaway.

Code: 
   movw   $0xcf8,%dx              ; dx = PCI address port (this is x86 architecture)
   movl   $0x80003840,%eax    ; eax = address of register 40h, function 0, device 7h, at bus 0
   outl   %eax,%dx                  ; "tell" the PCI device that we want to access register 40h in the next PCI cycle
   movb   $0xfc,%dl                 ; dx = 0xCFC = PCI data port (in x86 architecture)
   inl   %dx,%eax                    ; eax = dword starting at register 40h in the PCI device

This should be clear enough for you .

PS: The assembly language syntax is in AT&T syntax and it's an x86 (IBM-PC) architecture code. Look for AT&T syntax tutorial if you feel confused. IIRC, GAS (GNU Assembler) tutorial would be enough.
 

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