The System V Application Binary Interface is the calling convention used almost universally on x86_64. This is a quick reference of the registers used in function calls, since the official table is a bit messy.

Before call, the stack must be 16-byte aligned. The direction flag DF must also be clear. The 128-byte “red zone” below the current stack frame can be used for temporary data not preserved across function calls.

Linux system calls

For some reason the roles of rcx and r10 are swapped. Calls are made using the syscall instruction.