Control Intructions

[Dabdob]

Here are the control transfer instruction inerruot the sequential execution of instruction in memory and transfer control to some other point in memory either unconditionally or after testing the result of "CMP: instruction..

The Control Intructions are:

1-ja dest-----> Jump if above
2-jae dest -----> jump if above or equal
3-jb dest -----> jumo if below
4-jbe dest -----> jump if below or equal
5- je dest -----> jump if equal
6- jne dest -----> jump if not equal
7-jmp dest -----> Unconditional jump
8-irest -----> Return from an interrupt

Cheers
Dabdob

[Narue]

>either unconditionally or after testing the result of "CMP: instruction..
Or any instruction that modifies the appropriate flags. For example, I could say:

dec	ecx
jz	foo

To jump to foo when ecx reaches 0. Sometimes it's more efficient to avoid cmp in favor of a more implicit test.

>The Control Intructions are:
You're missing quite a few, but that's not as important as the distinction between the signed and unsigned representations. If you're doing something like this:

; Print [0,10) in reverse
	mov	eax,9
again:
	call	print_num
	dec	eax
	cmp	eax,0
	jae	again

jae is an unsigned condition, but it's used like the signed equivalent jge, and will result in an infinite loop because jae doesn't recognize negative values. When eax goes to -1, jae will see it as a large unsigned value.

>8-irest -----> Return from an interrupt
You should check your spelling when typing technical information. To my knowledge, there's no "irest" instruction in the x86 architecture. :)

I like your helpful attitude though, keep it up. :)

[Dabdob]

[QUOTE=Narue>8-irest -----> Return from an interrupt
You should check your spelling when typing technical information. To my knowledge, there's no "irest" instruction in the x86 architecture. :)

QUOTE]

Yes, it's "iret" sorry for my mistake :cry: