x86-64 Unix Utilities

Repository containing basic x86-64 NASM assembly utilties demonstrating Linux system calls.

Assembling and Linking

The utilities written in this repository are built around the NASM assembler which is a requirement for assembly. Additionally, it is using 64 bit mode which will need to be specified in the assembly command.

nasm -f elf64 src/printwd.asm -o build/printwd.o

There should now be an assembled object file in the build directory. The next step is to link-edit to an executable file.

ld build/printwd.o -o printwd

An executable file should now exist. If execute authority is permitted, the utility can now be used.

./printwd

Linux Syscall & NASM References

• NASM Tutorial
• Direct Operating System Access via Syscalls
• 64-bit Syscall Table