mm i need to check some values in some PE fields:

400
50

So EAX can be:

A3000
A3050
A3400
A3450 -> 400 + 50


I use:

cmp al,50h
jz this

and ax,1FFh
cmp ax,400h
jz that

But how to check for 400 if the value is 450 for example?

A3450 -> 400 + 50 (this+that)

and ax,1FFh
cmp ax,4xx?

dacid,

cmp al, 50h will jz for eax==0xffffff50 too…

After and ax, 1FFh ax will never be greater than 1FFh, not to mention equal to 400h…

Simple sequence of cmp eax, XXXh/je YYY will not work?

May be if you describe your problem more precisely…