In the last post I wrote about how the SHL and the SHR instructions can be used to multiply and divide by powers of 2. What if that’s not the case? What if a multiplication by a different number is required? Well, here we go… The MUL/IMUL instructions The MUL and IMUL (Integer MULtiplication) instructions […]

According the statistics I’m using as a referral, the next most common instruction is the comparison one CMP, but, actually, before explaining this one it’s necessary/useful to introduce other instuctions, just like ADD and SUB. The ADD and SUB instructions The ADD was vaguely introduced the last time and it just adds the source to […]

Just a few days ago I decided to give a look again at the disasm of the good old Cascade virus (somebody still recalls it? when they were just called “viruses” or “virii” pour les elitaires). Man, oh man, what a piece of malware was that (it fit in 1704 bytes)… Letters falling in the […]