Author Archives : xlogicx


Assembly is Too High Level: Commutative Property, Sometimes (it may save your byte)

I remember learning these properties in basic algebra: Associative, Distributive, and Commutative. It’s the Commutative property that states that a + b = b + a. The same principle is true with multiplication. In x86 pointer math, of course the results of these operations follow the commutative property; that’s just math. However, the machine encoding […]

apples

Boot Sector Graphical Programming (Tutorial)

This tutorial is aimed at those that have some assembly experience, but very minimal 16-bit BIOS programming experience, in other words; a short list of some of my friends that I want to coerce into doing some BIOS programming. Assembling: Qemu Assemble source: nasm yourboot.asm -f bin -o yourboot.bin Run with qemu: qemu tronsolitare.bin Run […]

goatse

SIBs04

Assembly is Too High Level: SIB Doubles 1

I’m finding that there is a full playground in the ModR/M encoding, and this post is specifically about a SIB obscurity, only because of the way I see NASM assembling some of my assembly. Then I found other cool things NASM puts up with Consider this code: Functionally, they both result in the same thing. […]