Control Intructions
 

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

Re: Control Intructions
 

>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. :)

Re: Control Intructions
 

[QUOTE=Narue>8-irest -----> Return from an interrupt
You should check your spelling when typing technical information. To my knowledge, there's no "ire[B]s[/B]t" instruction in the x86 architecture. :)

QUOTE]

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