Assembly

Syscalls numbers x86_64 intel/amd64 architecture

Chromium OS Docs - Linux System Call Table

linux/syscall_64.tbl at master · torvalds/linuxGitHub

Searchable Linux Syscall Table for x86 and x86_64 | PyTux

or

man -s 2 <syscall_name>>

Data Type

Component	Length	Example
byte	8 bits	0xab
word	16 bits - 2 bytes	0xabcd
double word (dword)	32 bits - 4 bytes	0xabcdef12
quad word (qword)	64 bits - 8 bytes	0xabcdef1234567890

Whenever we use a variable with a certain data type or use a data type with an instruction, both operands should be of the same size.