A bare metal brainf*ck interpreter written in pure assembly language.

You need fasm to assemble asmbrain.

$ fasm main.asm

The resulting file main.bin is ready executable.

Using QEMU should be okay.

$ qemu-system-i386 -fda main.bin

I suppose you know what you do.

Write asmbrain to USB stick:

$ dd if=main.bin of=/dev/sdX bs=512

Now you can boot from your USB stick.